WorldWideScience

Sample records for nanoscale silver thin

  1. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  2. Properties of electropolymerised polypyrrole thin film on silver

    Science.gov (United States)

    Jamadade, Shivaji A.; Puri, Vijaya

    2009-07-01

    This paper reports the properties of electropolymerised polypyrrole thin film on silver. The transmission, reflection, conductivity and dielectric behavior of polypyrrole coated silver has been studied in the 8-12 GHz frequency range of the electromagnetic spectrum. The polypyrrole thin film makes silver a better conductor for microwaves. The microwave conductivity is larger than the DC conductivity by many orders of magnitude. The real and imaginary part of dielectric constant increases in magnitude with increasing doping level and also it decreases in magnitude with increasing frequency.

  3. In vitro behaviour of nanocrystalline silver-sputtered thin films

    International Nuclear Information System (INIS)

    Piedade, A P; Vieira, M T; Martins, A; Silva, F

    2007-01-01

    Silver thin films were deposited with different preferential orientations and special attention was paid to the bioreactivity of the surfaces. The study was essentially focused on the evaluation of the films by x-ray diffraction (XRD), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), electron probe microanalysis (EPMA) and contact angle measurements. The deposited thin films were characterized before and after immersion in S-enriched simulated human plasma in order to estimate the influence of the preferential crystallographic orientation on the in vitro behaviour. Silver thin films with and without (111) preferential crystallographic orientation were deposited by r.f. magnetron sputtering to yield nanocrystalline coatings, high compact structures, very hydrophobic surfaces and low roughness. These properties reduce the chemisorption of reactive species onto the film surface. The in vitro tests indicate that silver thin films can be used as coatings for biomaterials applications

  4. Humidity effect on nanoscale electrochemistry in solid silver ion conductors and the dual nature of its locality.

    Science.gov (United States)

    Yang, Sang Mo; Strelcov, Evgheni; Paranthaman, M Parans; Tselev, Alexander; Noh, Tae Won; Kalinin, Sergei V

    2015-02-11

    Scanning probe microscopy (SPM) is a powerful tool to investigate electrochemistry in nanoscale volumes. While most SPM-based studies have focused on reactions at the tip-surface junction, charge and mass conservation requires coupled and intrinsically nonlocal cathodic and anodic processes that can be significantly affected by ambient humidity. Here, we explore the role of water in both cathodic and anodic processes, associated charge transport, and topographic volume changes depending on the polarity of tip bias. The first-order reversal curve current-voltage technique combined with simultaneous detection of the sample topography, referred to as FORC-IVz, was applied to a silver solid ion conductor. We found that the protons generated from water affect silver ionic conduction, silver particle formation and dissolution, and mechanical integrity of the material. This work highlights the dual nature (simultaneously local and nonlocal) of electrochemical SPM studies, which should be considered for comprehensive understanding of nanoscale electrochemistry.

  5. Antibacterial effects of silver-doped hydroxyapatite thin films sputter deposited on titanium

    International Nuclear Information System (INIS)

    Trujillo, Nathan A.; Oldinski, Rachael A.; Ma, Hongyan; Bryers, James D.; Williams, John D.; Popat, Ketul C.

    2012-01-01

    Since many orthopedic implants fail as a result of loosening, wear, and inflammation caused by repeated loading on the joints, coatings such as hydroxyapatite (HAp) on titanium with a unique topography have been shown to improve the interface between the implant and the natural tissue. Another serious problem with long-term or ideally permanent implants is infection. It is important to prevent initial bacterial colonization as existing colonies have the potential to become encased in an extracellular matrix polymer (biofilm) that is resistant to antibacterial agents. In this study, plasma-based ion implantation was used to examine the effects of pre-etching on plain titanium. Topographical changes to the titanium samples were examined and compared via scanning electron microscopy. Hydroxyapatite and silver-doped hydroxyapatite thin films were then sputter deposited on titanium substrates etched at − 700 eV. For silver-doped films, two concentrations of silver (∼ 0.5 wt.% and ∼ 1.5 wt.%) were used. Silver concentrations in the film were determined using energy dispersive X-ray spectroscopy. Hydroxyapatite film thicknesses were determined by measuring the surface profile using contact profilometry. Staphylococcus epidermidis and Pseudomonas aeruginosa adhesion studies were performed on plain titanium, titanium coated with hydroxyapatite, titanium coated with ∼ 0.5 wt.% silver-doped hydroxyapatite, and titanium coated with ∼ 1.5 wt.% silver-doped hydroxyapatite. Results indicate that less bacteria adhered to surfaces containing hydroxyapatite and silver; further, as the hydroxyapatite films delaminated, silver ions were released which killed bacteria in suspension. - Highlights: ► We have developed a combination of plasma-based ion implantation and ion beam sputter deposition technique. ► Silver-doped hydroxyapatite thin films on titanium were developed. ► The thin films showed the ability to control the concentration of silver that is doped within the

  6. Antimicrobial activity of thin solid films of silver doped hydroxyapatite prepared by sol-gel method.

    Science.gov (United States)

    Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

    2014-01-01

    In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with x(Ag) = 0.5 are effective against E. coli and S. aureus after 24 h.

  7. Antimicrobial Activity of Thin Solid Films of Silver Doped Hydroxyapatite Prepared by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Simona Liliana Iconaru

    2014-01-01

    Full Text Available In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM with energy Dispersive X-ray attachment (X-EDS, Fourier transform infrared spectroscopy (FT-IR, and glow discharge optical emission spectroscopy (GDOES. These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with xAg=0.5 are effective against E. coli and S. aureus after 24 h.

  8. Antimicrobial Activity of Thin Solid Films of Silver Doped Hydroxyapatite Prepared by Sol-Gel Method

    Science.gov (United States)

    Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

    2014-01-01

    In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with x Ag = 0.5 are effective against E. coli and S. aureus after 24 h. PMID:24523630

  9. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples

    Science.gov (United States)

    Cathcart, Nicole; Kitaev, Vladimir

    2016-09-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design.

  10. Nanoscale aluminum concaves for light-trapping in organic thin-films

    DEFF Research Database (Denmark)

    Goszczak, Arkadiusz Jaroslaw; Adam, Jost; Cielecki, Pawel Piotr

    2016-01-01

    Anodic aluminum oxide (AAO) templates, fabricated from oxalic acid and phosphoric acid, lead to non-periodic nanoscale concave structures in their underlying aluminum layer, which are investigated for their field-enhancement properties by applying a thin-film polymer coating based laser ablation...

  11. Preparation and Characterization of Silver Liquid Thin Films for Magnetic Fluid Deformable Mirror

    Directory of Open Access Journals (Sweden)

    Lianchao Zhang

    2015-01-01

    Full Text Available Silver liquid thin film, formed by silver nanoparticles stacking and spreading on the surface of the liquid, is one of the important parts of magnetic fluid deformable mirror. First, silver nanoparticles were prepared by liquid phase chemical reduction method using sodium citrate as reducing agent and stabilizer and silver nitrate as precursor. Characterization of silver nanoparticles was studied using X-ray diffractometer, UV-vis spectrophotometer, and transmission electron microscope (TEM. The results showed that silver nanoparticles are spherical and have a good monodispersity. Additionally, the effect of the reaction conditions on the particle size of silver is obvious. And then silver liquid thin films were prepared by oil-water two-phase interface technology using as-synthesized silver nanoparticles. Properties of the film were investigated using different technology. The results showed that the film has good reflectivity and the particle size has a great influence on the reflectivity of the films. SEM photos showed that the liquid film is composed of multilayer silver nanoparticles. In addition, stability of the film was studied. The results showed that after being stored for 8 days under natural conditions, the gloss and reflectivity of the film start to decrease.

  12. Multiple surface plasmon polaritons modes on thin silver film controlled by a two-dimensional lattice of silver nanodimers

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ying; Jiang, Yongyuan, E-mail: jiangyy@hit.edu.cn [Harbin Institute of Technology, Department of Physics (China)

    2015-01-15

    We study the optical resonant spectrum of a two-dimensional periodic array of silver nanodimers on a thin silver film using multiple scattering formalism. The excited multiple plasmonic modes on two interfaces of the silver film reveal that the dispersion relationships of surface plasmon polaritons on metallic film are modified by doubly periodic lattice due to the fact that wave vectors matching conditions are satisfied. Moreover, we demonstrate that the plasmonic modes are directly controlled by the thickness of silver film, as well as the gap between nanodimer array and silver film. These effects provide novel high-efficient and steady way for excitation in future plasmonic nanodevices.

  13. Silver loaded WO3−x/TiO2 composite multifunctional thin films

    International Nuclear Information System (INIS)

    Dunnill, Charles W.; Noimark, Sacha; Parkin, Ivan P.

    2012-01-01

    Multifunctional WO 3−x –TiO 2 composite thin films have been prepared by sol–gel synthesis and shown to be good visible light photocatalysts whilst retaining a desirable underlying blue colouration. The WO 3−x –TiO 2 composite thin films were further enhanced using silver nanoparticles synthesised in-situ on the surface from the photo-degradation of silver nitrate solution. Thin films were characterised using X-ray diffraction, Raman, Scanning electron microscopy and UV–visible spectroscopy and shown to photo degrade stearic acid, using white light λ = 420–800 nm. - Highlights: ► WO 3−X TiO 2 composite thin films were synthesised by sol–gel methods. ► Blue tinted glass is desirable for the value added glass industry. ► Silver nanoparticle island formation enhances the activity of the films. ► Blue tinted “value added” coated glass is now possible.

  14. Structural and surface compositional characterization of silver thin ...

    African Journals Online (AJOL)

    Silver thin films were deposited on microscope glass slides by the electroless Solution Growth Technique (SGT). The films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). The films were found to exhibit a random orientation with peak positions ...

  15. Silver loaded WO{sub 3-x}/TiO{sub 2} composite multifunctional thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dunnill, Charles W.; Noimark, Sacha; Parkin, Ivan P., E-mail: I.P.Parkin@ucl.ac.uk

    2012-06-30

    Multifunctional WO{sub 3-x}-TiO{sub 2} composite thin films have been prepared by sol-gel synthesis and shown to be good visible light photocatalysts whilst retaining a desirable underlying blue colouration. The WO{sub 3-x}-TiO{sub 2} composite thin films were further enhanced using silver nanoparticles synthesised in-situ on the surface from the photo-degradation of silver nitrate solution. Thin films were characterised using X-ray diffraction, Raman, Scanning electron microscopy and UV-visible spectroscopy and shown to photo degrade stearic acid, using white light {lambda} = 420-800 nm. - Highlights: Black-Right-Pointing-Pointer WO{sub 3-X} TiO{sub 2} composite thin films were synthesised by sol-gel methods. Black-Right-Pointing-Pointer Blue tinted glass is desirable for the value added glass industry. Black-Right-Pointing-Pointer Silver nanoparticle island formation enhances the activity of the films. Black-Right-Pointing-Pointer Blue tinted 'value added' coated glass is now possible.

  16. Silver Nanoparticle Enhanced Freestanding Thin-Film Silicon Solar Cells

    Science.gov (United States)

    Winans, Joshua David

    As the supply of fossil fuels diminishes in quantity the demand for alternative energy sources will consistently increase. Solar cells are an environmentally friendly and proven technology that suffer in sales due to a large upfront cost. In order to help facilitate the transition from fossil fuels to photovoltaics, module costs must be reduced to prices well below $1/Watt. Thin-film solar cells are more affordable because of the reduced materials costs, but lower in efficiency because less light is absorbed before passing through the cell. Silver nanoparticles placed at the front surface of the solar cell absorb and reradiate the energy of the light in ways such that more of the light ends being captured by the silicon. Silver nanoparticles can do this because they have free electron clouds that can take on the energy of an incident photon through collective action. This bulk action of the electrons is called a plasmon. This work begins by discussing the economics driving the need for reduced material use, and the pros and cons of taking this step. Next, the fundamental theory of light-matter interaction is briefly described followed by an introduction to the study of plasmonics. Following that we discuss a traditional method of silver nanoparticle formation and the initial experimental studies of their effects on the ability of thin-film silicon to absorb light. Then, Finite-Difference Time-Domain simulation software is used to simulate the effects of nanoparticle morphology and size on the scattering of light at the surface of the thin-film.

  17. In situ observations of crack arrest and bridging by nanoscale twins in copper thin films

    International Nuclear Information System (INIS)

    Kim, Seong-Woong; Li Xiaoyan; Gao Huajian; Kumar, Sharvan

    2012-01-01

    In situ tensile experiments in a transmission electron microscope revealed that micro-cracks in ultrafine grained, free-standing, thin copper foils containing nanoscale twins initiated in matrix domains separated by the twins and then arrested at twin boundaries as twin boundary sliding proceeded. The adjacent microcracks eventually coalesced through shear failure of the bridging twins. To investigate the atomic mechanism of this rarely seen nanoscale crack bridging behavior, molecular dynamics simulations were performed to show that during crack propagation twin boundaries are impinged upon by numerous dislocations from the plastically deforming matrix. These dislocations react at the interface and evolve into substantially impenetrable dislocation walls that strongly confine crack nucleation and resist crack propagation, leading to the experimentally observed crack bridging behavior. The present results raise an approach to significantly toughening polycrystalline thin films by incorporating nanoscale twin structures into individual grains that serve as crack bridging ligaments.

  18. Simulations of quantum transport in nanoscale systems: application to atomic gold and silver wires

    DEFF Research Database (Denmark)

    Mozos, J.L.; Ordejon, P.; Brandbyge, Mads

    2002-01-01

    . The potential drop profile and induced electronic current (and therefore the conductance) are obtained from first principles. The method takes into account the atomic structure of both the nanoscale structure and the semi-infinite electrodes through which the potential is applied. Non-equilibrium Green......'s function techniques are used to calculate the quantum conductance. Here we apply the method to the study of the electronic transport in wires of gold and silver with atomic thickness. We show the results of our calculations, and compare with some of the abundant experimental data on these systems....

  19. Facile green synthesis of silver nanodendrite/cellulose acetate thin film electrodes for flexible supercapacitors.

    Science.gov (United States)

    Devarayan, Kesavan; Park, Jiyoung; Kim, Hak-Yong; Kim, Byoung-Suhk

    2017-05-01

    In this study, we present a highly efficient and economical solution called as 'in situ hydrogenation' for preparation of highly conductive thin film electrode based on silver nanodendrites. The silver nanodendrite (AgND)/cellulose acetate (CA) thin film electrodes exhibited sheet resistance ranging from 0.32ohm/sq to 122.1ohm/sq which could be controlled by changing the concentration of both silver and polymer. In addition, these electrodes exhibited outstanding toughness during the bending test. Further, these thin film electrodes have great potential for scale-up with an average weight of 3mg/cm 2 and can be also combined with active nanomaterials such as multiwalled carbon nanotubes (MWCNTs) to fabricate AgND/CA/MWCNTs thin film for high-performance flexible supercapacitor electrode. The AgND/CA/MWCNTs electrodes exhibited a maximum specific capacitance of 237F/g at a current density of 0.3A/g. After 1000 cycles, the AgND/MWCNT/CA exhibited a decrease of 16.0% of specific capacitance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Evaluation of the Antimicrobial Activity of Different Antibiotics Enhanced with Silver-Doped Hydroxyapatite Thin Films

    Directory of Open Access Journals (Sweden)

    Daniela Predoi

    2016-09-01

    Full Text Available The inhibitory and antimicrobial effects of silver particles have been known since ancient times. In the last few years, a major health problem has arisen due to pathogenic bacteria resistance to antimicrobial agents. The antibacterial activities of new materials including hydroxyapatite (HAp, silver-doped hydroxyapatite (Ag:HAp and various types of antibiotics such as tetracycline (T-HAp and T-Ag:HAp or ciprofloxacin (C-HAp and C-Ag:HAp have not been studied so far. In this study we reported, for the first time, the preparation and characterization of various thin films based on hydroxyapatite and silver-doped hydroxyapatite combined with tetracycline or ciprofloxacin. The structural and chemical characterization of hydroxyapatite and silver-doped hydroxyapatite thin films has been evaluated by X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FTIR. The morphological studies of the HAp, Ag:HAp, T-HAp, T-Ag:HAp, C-HAp and C-Ag:HAp thin solid films were performed using scanning electron microscopy (SEM. In order to study the chemical composition of the coatings, energy dispersive X-ray analysis (EDX and glow discharge optical emission spectroscopy (GDOES measurements have been used, obtaining information on the distribution of the elements throughout the film. These studies have confirmed the purity of the prepared hydroxyapatite and silver-doped hydroxyapatite thin films obtained from composite targets containing Ca10−xAgx(PO46(OH2 with xAg = 0 (HAp and xAg = 0.2 (Ag:HAp. On the other hand, the major aim of this study was the evaluation of the antibacterial activities of ciprofloxacin and tetracycline in the presence of HAp and Ag:HAp thin layers against Staphylococcus aureus and Escherichia coli strains. The antibacterial activities of ciprofloxacin and tetracycline against Staphylococcus aureus and Escherichia coli test strains increased in the presence of HAp and Ag:HAp thin layers.

  1. Nanoscale silver-assisted wet etching of crystalline silicon for anti-reflection surface textures.

    Science.gov (United States)

    Li, Rui; Wang, Shuling; Chuwongin, Santhad; Zhou, Weidong

    2013-01-01

    We report here an electro-less metal-assisted chemical etching (MacEtch) process as light management surface-texturing technique for single crystalline Si photovoltaics. Random Silver nanostructures were formed on top of the Si surface based on the thin film evaporation and annealing process. Significant reflection reduction was obtained from the fabricated Si sample, with approximately 2% reflection over a wide spectra range (300 to 1050 nm). The work demonstrates the potential of MacEtch process for anti-reflection surface texture fabrication of large area, high efficiency, and low cost thin film solar cell.

  2. Plasmon hybridization in silver nanoislands as semishell arrays coupled to a thin metallic film

    DEFF Research Database (Denmark)

    Maaroof, Abbas; Nygaard, Jens Vinge; Sutherland, Duncan S

    2011-01-01

    We obtained experimentally strong plasmon interactions between localized surface plasmon with delocalized surface plasmon polaritons in a new nanosystem of silver semishells island film arrays arranged as a closed-packing structure coupled to an adjacent thin silver film. We show that plasmon int...

  3. A Humidity Sensor Based on Silver Nanoparticles Thin Film Prepared by Electrostatic Spray Deposition Process

    Directory of Open Access Journals (Sweden)

    Thutiyaporn Thiwawong

    2013-01-01

    Full Text Available In this work, thin film of silver nanoparticles for humidity sensor application was deposited by electrostatic spray deposition technique. The influence of the deposition times on properties of films was studied. The crystal structures of sample films, their surface morphology, and optical properties have been investigated by X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, and UV-VIS spectrophotometer, respectively. The crystalline structure of silver nanoparticles thin film was found in the orientation of (100 and (200 planes of cubic structure at diffraction angles 2θ  =  38.2° and 44.3°, respectively. Moreover, the silver nanoparticles thin films humidity sensor was fabricated onto the interdigitated electrodes. The sensor exhibited the humidity adsorption and desorption properties. The sensing mechanisms of the device were also elucidated by complex impedance analysis.

  4. Electromagnetic shielding effectiveness of a thin silver layer deposited onto PET film via atmospheric pressure plasma reduction

    Science.gov (United States)

    Oh, Hyo-Jun; Dao, Van-Duong; Choi, Ho-Suk

    2018-03-01

    This study presents the first use of a plasma reduction reaction under atmospheric pressure to fabricate a thin silver layer on polyethylene terephthalate (PET) film without the use of toxic chemicals, high voltages, or an expensive vacuum apparatus. The developed film is applied to electromagnetic interference (EMI) shielding. After repeatedly depositing a silver layer through a plasma reduction reaction on PET, we can successfully fabricate a uniformly deposited thin silver layer. It was found that both the particle size and film thickness of thin silver layers fabricated at different AgNO3 concentrations increase with an increase in the concentration of AgNO3. However, the roughness of the thin silver layer decreases when increasing the concentration of AgNO3 from 100 to 500 mM, and the roughness increases with a further increase in the concentration of AgNO3. The EMI shielding effectiveness (SE) of the film is measured in the frequency range of 0.045 to 1 GHz. As a result of optimizing the electrical conductivity by measuring sheet resistance of the thin silver layer, the film fabricated from 500 mM AgNO3 exhibits the highest EMI SE among all fabricated films. The maximum values of the EMI SE are 60.490 dB at 0.1 GHz and 54.721 dB at 1.0 GHz with minimum sheet resistance of 0.244 Ω/□. Given that the proposed strategy is simple and effective, it is promising for fabricating various low-cost metal films with high EMI SE.

  5. Adhesion Dynamics in Probing Micro- and Nanoscale Thin Solid Films

    Directory of Open Access Journals (Sweden)

    Xiaoling He

    2008-01-01

    Full Text Available This study focuses on modeling the probe dynamics in scratching and indenting thin solid films at micro- and nanoscales. The model identifies bifurcation conditions that define the stick-slip oscillation patterns of the tip. It is found that the local energy fluctuations as a function of the inelastic deformation, defect formation, material properties, and contact parameters determine the oscillation behavior. The transient variation of the localized function makes the response nonlinear at the adhesion junction. By quantifying the relation between the bifurcation parameters and the oscillation behavior, this model gives a realistic representation of the complex adhesion dynamics. Specifically, the model establishes the link between the stick-slip behavior and the inelastic deformation and the local potentials. This model justifies the experimental observations and the molecular dynamics simulation of the adhesion and friction dynamics in both the micro- and nanoscale contact.

  6. The influence of nanoscopically thin silver films on bacterial viability and attachment.

    Science.gov (United States)

    Ivanova, Elena P; Hasan, Jafar; Truong, Vi Khanh; Wang, James Y; Raveggi, Massimo; Fluke, Christopher; Crawford, Russell J

    2011-08-01

    The physicochemical and bactericidal properties of thin silver films have been analysed. Silver films of 3 and 150 nm thicknesses were fabricated using a magnetron sputtering thin-film deposition system. X-ray photoelectron and energy dispersive X-ray spectroscopy and atomic force microscopy analyses confirmed that the resulting surfaces were homogeneous, and that silver was the most abundant element present on both surfaces, being 45 and 53 at.% on the 3- and 150-nm films, respectively. Inductively coupled plasma time of flight mass spectroscopy (ICP-TOF-MS) was used to measure the concentration of silver ions released from these films. Concentrations of 0.9 and 5.2 ppb were detected for the 3- and 150-nm films, respectively. The surface wettability of the films remained nearly identical for both film thicknesses, displaying a static water contact angle of 95°, while the surface free energy of the 150-nm film was found to be slightly greater than that of the 3-nm film, being 28.8 and 23.9 mN m(-1), respectively. The two silver film thicknesses exhibited statistically significant differences in surface topographic profiles on the nanoscopic scale, with R (a), R (q) and R (max) values of 1.4, 1.8 and 15.4 nm for the 3-nm film and 0.8, 1.2 and 10.7 nm for the 150-nm film over a 5 × 5 μm scanning area. Confocal scanning laser microscopy and scanning electron microscopy revealed that the bactericidal activity of the 3-nm silver film was not significant, whereas the nanoscopically smoother 150-nm silver film exhibited appreciable bactericidal activity towards Pseudomonas aeruginosa ATCC 9027 cells and Staphylococcus aureus CIP 65.8 cells, obtaining up to 75% and 27% sterilisation effect, respectively.

  7. Sintering of nanoscale silver coated textiles, a new approach to attain conductive fabrics for electromagnetic shielding

    International Nuclear Information System (INIS)

    Kardarian, Kasra; Busani, Tito; Osório, Inês; Domingos, Helena; Igreja, Rui; Franco, Ricardo; Cortez, João

    2014-01-01

    The demand for conductive textiles is increasing, owing to the need for lightweight and flexible conductive materials for a variety of applications, including electromagnetic shielding of electronic equipment. Herein we propose a process that combines the in situ synthesis of silver nanoparticles at the textile fibre surface followed by sintering of the nanoparticles to obtain highly conductive fabrics. The formation of silver particles at the nanoscale allowed for sintering to be performed efficiently, at reduced temperature and time, bestowing fabrics with high conductivity and capability of shielding electromagnetic radiation. The nanoparticle synthesis method entailed the precipitation of 2.0 g L −1 silver nitrate and further reduction with citrate, with the formation of a deposit of silver nanoparticles at the fabric surface. The amount of silver deposited (up to 195 mg of silver per g of fabric) resulted in moderate electrical conductivity with sheet resistance of 803 Ω/sq. Upon sintering, this value decreased dramatically to 5.2 Ω/sq. The sintering process was monitored by SEM, which showed that sintering at 200 °C for 30 min resulted in maximal electrical conductivity with the lowest amount of silver deposited, while forming a homogenous surface. Fabrics submitted to these sintering conditions maintained their sheet resistance and shielding effectiveness values, even after eight washing cycles. - Highlights: • Assembly of highly conductive textiles capable of shielding electromagnetic radiation. • Procedure combines in situ synthesis of AgNPs at the textile surface and sintering. • AgNPs formed by precipitation of AgNO 3 and reduction with citrate, as observed by SEM. • Sintering increased dramatically conductivity and shielding effectiveness. • Treated fabrics maintained conductivity and shielding effectiveness after 8 washes

  8. Sintering of nanoscale silver coated textiles, a new approach to attain conductive fabrics for electromagnetic shielding

    Energy Technology Data Exchange (ETDEWEB)

    Kardarian, Kasra [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Busani, Tito [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Osório, Inês [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Domingos, Helena; Igreja, Rui [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Franco, Ricardo [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Cortez, João, E-mail: j.cortez@fct.unl.pt [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal)

    2014-10-15

    The demand for conductive textiles is increasing, owing to the need for lightweight and flexible conductive materials for a variety of applications, including electromagnetic shielding of electronic equipment. Herein we propose a process that combines the in situ synthesis of silver nanoparticles at the textile fibre surface followed by sintering of the nanoparticles to obtain highly conductive fabrics. The formation of silver particles at the nanoscale allowed for sintering to be performed efficiently, at reduced temperature and time, bestowing fabrics with high conductivity and capability of shielding electromagnetic radiation. The nanoparticle synthesis method entailed the precipitation of 2.0 g L{sup −1} silver nitrate and further reduction with citrate, with the formation of a deposit of silver nanoparticles at the fabric surface. The amount of silver deposited (up to 195 mg of silver per g of fabric) resulted in moderate electrical conductivity with sheet resistance of 803 Ω/sq. Upon sintering, this value decreased dramatically to 5.2 Ω/sq. The sintering process was monitored by SEM, which showed that sintering at 200 °C for 30 min resulted in maximal electrical conductivity with the lowest amount of silver deposited, while forming a homogenous surface. Fabrics submitted to these sintering conditions maintained their sheet resistance and shielding effectiveness values, even after eight washing cycles. - Highlights: • Assembly of highly conductive textiles capable of shielding electromagnetic radiation. • Procedure combines in situ synthesis of AgNPs at the textile surface and sintering. • AgNPs formed by precipitation of AgNO{sub 3} and reduction with citrate, as observed by SEM. • Sintering increased dramatically conductivity and shielding effectiveness. • Treated fabrics maintained conductivity and shielding effectiveness after 8 washes.

  9. Surface microtopography of thin silver films

    Science.gov (United States)

    Costa, Manuel F. M.; Almeida, Jose B.

    1991-01-01

    The authors present ne applications for the recently developed nori-contact optical inicrotopographer emphasizing the results of topographic inspections of thin silver films edges. These films were produced by sputtering of silver through different masks, using a planar magnetron source. The results show the influence ot the thickness and position of the masks on the topography of the film near its edge. Topographic information is obtained from the horizontal shift incurred by the bright spot on an horizontal surface, which is displaced vertically, when this is illuminated by an oblique collimated laser beam. The laser beam is focused onto the surface into a diffraction limited spot and is made to sweep the surface to be examined.. The horizontal position of the bright spot is continuously imaged onto a light detector array and the information about individual detectors that are activated is used to compute the corresponding horizontal shift on the reference plane. Simple trignometric calculations are used to relate the horizontal shift to the distance between the surface and a reference plane at each sampling point and thus a map of the surface topography can be built.

  10. UV and plasma treatment of thin silver layers and glass surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hluschi, J.H. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Helmke, A. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Roth, P. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany); Boewer, R. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Herlitze, L. [Interpane Glasbeschichtungsgesellschaft mbH and Co KG, Sohnreystr. 21, D-37697 Lauenfoerde (Germany); Vioel, W. [University of Applied Sciences and Arts, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany)]. E-mail: vioel@hawk-hhg.de

    2006-11-10

    Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of {lambda}=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers.

  11. UV and plasma treatment of thin silver layers and glass surfaces

    International Nuclear Information System (INIS)

    Hluschi, J.H.; Helmke, A.; Roth, P.; Boewer, R.; Herlitze, L.; Vioel, W.

    2006-01-01

    Thin silver layers can be modified by treatment with UV radiation or a plasma discharge. UV treatment at a wavelength of λ=308 -bar nm improves the layer properties, thus leading to an enhancement of the layers IR reflectivity. For the purpose of in situ-measurement the sheet resistance is recorded during the process. Due to the Hagen-Rubens-Relation [E. Hagen, H. Rubens, Ann. Phys. 11 (1903) 873]-bar the sheet resistance is linked to the IR reflectivity of thin metal-films. A pretreatment of uncoated glass using a dielectric barrier discharge activates and cleans its surface, thus leading to an increase in adhesion of thin layers

  12. Gold and silver thin film analysis by optical and neutron activation techniques

    International Nuclear Information System (INIS)

    Moharram, B.M.; El-Khatib, A.M.; Ammar, E.A.

    1989-01-01

    Thicknesses of gold and silver thin films have been determined by NAA technique. Reasonable agreement with conventional optical methods has been obtained, but the lower detection limit in the case of NAA is far better than in the optical method. (author)

  13. Silver nanoparticle formation in thin oxide layer on silicon by silver-negative-ion implantation for Coulomb blockade at room temperature

    International Nuclear Information System (INIS)

    Tsuji, Hiroshi; Arai, Nobutoshi; Matsumoto, Takuya; Ueno, Kazuya; Gotoh, Yasuhito; Adachi, Kouichiro; Kotaki, Hiroshi; Ishikawa, Junzo

    2004-01-01

    Formation of silver nanoparticles formed by silver negative-ion implantation in a thin SiO 2 layer and its I-V characteristics were investigated for development single electron devices. In order to obtain effective Coulomb blockade phenomenon at room temperature, the isolated metal nanoparticles should be in very small size and be formed in a thin insulator layer such as gate oxide on the silicon substrate. Therefore, conditions of a fine particles size, high particle density and narrow distribution should be controlled at their formation without any electrical breakdown of the thin insulator layer. We have used a negative-ion implantation technique with an advantage of 'charge-up free' for insulators, with which no breakdown of thin oxide layer on Si was obtained. In the I-V characteristics with Au electrode, the current steps were observed with a voltage interval of about 0.12 V. From the step voltage the corresponded capacitance was calculated to be 0.7 aF. In one nanoparticle system, this value of capacitance could be given by a nanoparticle of about 3 nm in diameter. This consideration is consistent to the measured particle size in the cross-sectional TEM observation. Therefore, the observed I-V characteristics with steps are considered to be Coulomb staircase by the Ag nanoparticles

  14. Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jiezhu; Wang Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Haque, M A [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-05-26

    We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

  15. Studies on electrodeposited silver sulphide thin films by double exposure holographic interferometry

    International Nuclear Information System (INIS)

    Prabhune, V.B.; Shinde, N.S.; Fulari, V.J.

    2008-01-01

    Silver sulphide (Ag 2 S) thin films have been deposited on to stainless steel and fluorine doped tin oxide (FTO) glass substrates by the electrodeposition process, in potentiostatic mode using silver nitrate (AgNO 3 ), sodium thiosulphate (Na 2 S 2 O 3 ) as a precursor sources and Ethylene Diamine Tetra Acetic Acid (EDTA) was used as a complexing agent. The deposition potential of the compound was investigated by cyclic voltammetry. The structural and optical properties of the deposited films have been studied using X-ray diffraction (XRD) and optical absorption techniques, respectively. XRD studies reveal that the films are polycrystalline with monoclinic crystal structure. Optical absorption study shows the presence of direct transition with bandgap energy 1.1 eV. The determination of thickness and stress of the Ag 2 S thin films was carried out by Double Exposure Holographic Interferometry (DEHI) technique.

  16. Photocatalytic decomposition of diclofenac potassium using silver-modified TiO2 thin films

    International Nuclear Information System (INIS)

    Cavalheiro, A.A.; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O.

    2008-01-01

    The effects of silver insertion on the TiO 2 photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO 2 thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO 2 anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg C W -1 when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material

  17. The antibacterial and hydrophilic properties of silver-doped TiO{sub 2} thin films using sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xuemin [College of Physics and Electronic Information, Tianjin Normal University, Tianjin, 300387 (China); Hou Xinggang, E-mail: hou226@163.com [College of Physics and Electronic Information, Tianjin Normal University, Tianjin, 300387 (China); Luan Weijiang [College of Biology, Tianjin Normal University, Tianjin, 300387 (China); Li Dejun; Yao Kun [College of Physics and Electronic Information, Tianjin Normal University, Tianjin, 300387 (China)

    2012-08-01

    Ag-TiO{sub 2} composite thin films were deposited on glass slides by sol-gel spin coating technique. The surface structure, chemical components and transmittance spectra were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectrophotometer. The TiO{sub 2} thin films with silver molar ratio from 0 to 10% were tested for its antibacterial property by using Escherichia coliform (E. coli) under irradiation of UV light. The concentration of E. coli was evaluated by plating technique. The influences of different molar ratio of Ag on hydrophilicity and long-term durability of the films were also investigated by measuring the water contact angle. The results showed that the antibacterial ability was significantly improved by increasing silver content comparing with pure TiO{sub 2} thin film, and the best molar ratio of Ag was 5%. While the hydrophilicity of films increased with increasing silver content, and the best molar ratio of Ag was 1%.

  18. Photocatalytic decomposition of diclofenac potassium using silver-modified TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cavalheiro, A.A. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)], E-mail: albecava@bol.com.br; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)

    2008-07-31

    The effects of silver insertion on the TiO{sub 2} photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO{sub 2} thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO{sub 2} anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg{sub C} W{sup -1} when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material.

  19. Optical characterizations of silver nanoprisms embedded in polymer thin film layers

    Science.gov (United States)

    Carlberg, Miriam; Pourcin, Florent; Margeat, Olivier; Le Rouzo, Judikael; Berginc, Gerard; Sauvage, Rose-Marie; Ackermann, Jorg; Escoubas, Ludovic

    2017-10-01

    The precise control of light-matter interaction has a wide range of applications and is currently driven by the use of nanoparticles (NPs) by the recent advances in nanotechnology. Taking advantage of the material, size, shape, and surrounding media dependence of the optical properties of plasmonic NPs, thin film layers with tunable optical properties are achieved. The NPs are synthesized by wet chemistry and embedded in a polyvinylpyrrolidone (PVP) polymer thin film layer. Spectrophotometer and spectroscopic ellipsometry measurements are coupled to finite-difference time domain numerical modeling to optically characterize the heterogeneous thin film layers. Silver nanoprisms of 10 to 50 nm edge size exhibit high absorption through the visible wavelength range. A simple optical model composed of a Cauchy law and a Lorentz law, accounting for the optical properties of the nonabsorbing polymer and the absorbing property of the nanoprisms, fits the spectroscopic ellipsometry measurements. Knowing the complex optical indices of heterogeneous thin film layers let us design layers of any optical properties.

  20. Patterning high explosives at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Nafday, Omkar A.; Pitchimani, Rajasekar; Weeks, Brandon L. [Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409 (United States); Haaheim, Jason [NanoInk Inc., 8025 Lamon Ave., Skokie, IL 60077 (United States)

    2006-10-15

    For the first time, we have shown that spin coating and Dip pen nanolithography (DPN trademark) are simple methods of preparing energetic materials such as PETN and HMX on the nanoscale, requiring no heating of the energetic material. Nanoscale patterning has been demonstrated by the DPN method while continuous thin films were produced using the spin coating method. Results are presented for preparing continuous PETN thin films of nanometer thickness by the spin coating method and for controlling the architecture of arbitrary nanoscale patterns of PETN and HMX by the DPN method. These methods are simple for patterning energetic materials and can be extended beyond PETN and HMX, opening the door for fundamental studies at the nanoscale. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  1. In situ Silver Spot Preparation and on-Plate Surface-Enhanced Raman Scattering Detection in Thin Layer Chromatography Separation

    Science.gov (United States)

    Herman, K.; Mircescu, N. E.; Szabo, L.; Leopold, L. F.; Chiş, V.; Leopold, N.

    2013-05-01

    An improved approach for surface-enhanced Raman scattering (SERS) detection of mixture constituents after thin layer chromatography (TLC) separation is presented. A SERS active silver substrate was prepared under open air conditions, directly on the thin silica film by photo-reduction of silver nitrate, allowing the detection of binary mixtures of cresyl violet, bixine, crystal violet, and Cu(II) complex of 4-(2-pyridylazo)resorcinol. The recorded SERS spectrum provides a unique spectral fingerprint for each molecule; therefore the use of analyte standards is avoided, thus rendering the presented procedure advantageous compared to the conventional detection methodology in TLC.

  2. Enhancing Light-Trapping Properties of Amorphous Si Thin-Film Solar Cells Containing High-Reflective Silver Conductors Fabricated Using a Nonvacuum Process

    Directory of Open Access Journals (Sweden)

    Jun-Chin Liu

    2014-01-01

    Full Text Available We proposed a low-cost and highly reflective liquid organic sheet silver conductor using back contact reflectors in amorphous silicon (a-Si single junction superstrate configuration thin-film solar cells produced using a nonvacuum screen printing process. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (Jsc of sheet silver conductor cells was higher than 1.25 mA/cm2. Using external quantum efficiency measurements, the sheet silver conductor using back contact reflectors in cells was observed to effectively enhance the light-trapping ability in a long wavelength region (between 600 nm and 800 nm. Consequently, we achieved an optimal initial active area efficiency and module conversion efficiency of 9.02% and 6.55%, respectively, for the a-Si solar cells. The results indicated that the highly reflective sheet silver conductor back contact reflector layer prepared using a nonvacuum process is a suitable candidate for high-performance a-Si thin-film solar cells.

  3. Nanoscale ferroelectrics and multiferroics key processes and characterization issues, and nanoscale effects

    CERN Document Server

    Alguero, Miguel

    2016-01-01

    This book reviews the key issues in processing and characterization of nanoscale ferroelectrics and multiferroics, and provides a comprehensive description of their properties, with an emphasis in differentiating size effects of extrinsic ones like boundary or interface effects. Recently described nanoscale novel phenomena are also addressed. Organized into three parts it addresses key issues in processing (nanostructuring), characterization (of the nanostructured materials) and nanoscale effects. Taking full advantage of the synergies between nanoscale ferroelectrics and multiferroics, it covers materials nanostructured at all levels, from ceramic technologies like ferroelectric nanopowders, bulk nanostructured ceramics and thick films, and magnetoelectric nanocomposites, to thin films, either polycrystalline layer heterostructures or epitaxial systems, and to nanoscale free standing objects with specific geometries, such as nanowires and tubes at different levels of development. The book is developed from t...

  4. Investigation of the Structural, Electrical, and Optical Properties of the Nano-Scale GZO Thin Films on Glass and Flexible Polyimide Substrates

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2016-05-01

    Full Text Available In this study, Ga2O3-doped ZnO (GZO thin films were deposited on glass and flexible polyimide (PI substrates at room temperature (300 K, 373 K, and 473 K by the radio frequency (RF magnetron sputtering method. After finding the deposition rate, all the GZO thin films with a nano-scale thickness of about 150 ± 10 nm were controlled by the deposition time. X-ray diffraction patterns indicated that the GZO thin films were not amorphous and all exhibited the (002 peak, and field emission scanning electron microscopy showed that only nano-scale particles were observed. The dependences of the structural, electrical, and optical properties of the GZO thin films on different deposition temperatures and substrates were investigated. X-ray photoemission spectroscopy (XPS was used to measure the elemental composition at the chemical and electronic states of the GZO thin films deposited on different substrates, which could be used to clarify the mechanism of difference in electrical properties of the GZO thin films. In this study, the XPS binding energy spectra of Ga2p3/2 and Ga2p1/2 peaks, Zn2p3/2 and Zn2p1/2 peaks, the Ga3d peak, and O1s peaks for GZO thin films on glass and PI substrates were well compared.

  5. Surface effects on the electroelastic responses of a thin piezoelectric plate with nanoscale thickness

    International Nuclear Information System (INIS)

    Yan Zhi; Jiang Liying

    2012-01-01

    This work aims to investigate the electroelastic responses of a thin piezoelectric plate under mechanical and electrical loads with the consideration of surface effects. Surface effects, including surface elasticity, residual surface stress and surface piezoelectricity, are incorporated into the conventional Kirchhoff plate theory for a piezoelectric plate via the surface piezoelectricity model and the generalized Young-Laplace equations. Different from the results predicted by the conventional plate theory ignoring the surface effects, the proposed model predicts size-dependent behaviours of the piezoelectric thin plate with nanoscale thickness. It is found that surface effects have significant influence on the electroelastic responses of the piezoelectric nanoplate. This work is expected to provide more accurate predictions on characterizing nanofilm or nanoribbon based piezoelectric devices in nanoelectromechanical systems. (paper)

  6. Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Barik, Ullash; Srinivasan, S; Nagendra, C L; Subrahmanyam, A

    2003-04-01

    Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson.

  7. Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

    International Nuclear Information System (INIS)

    Kumar Barik, Ullash; Srinivasan, S.; Nagendra, C.L.; Subrahmanyam, A.

    2003-01-01

    Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson

  8. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    International Nuclear Information System (INIS)

    Cristescu, R.; Visan, A.; Socol, G.; Surdu, A.V.; Oprea, A.E.; Grumezescu, A.M.; Chifiriuc, M.C.; Boehm, R.D.; Yamaleyeva, D.; Taylor, M.; Narayan, R.J.; Chrisey, D.B.

    2016-01-01

    Highlights: • We successfully deposited composite quercetin dehydrate-, resveratrol- and silver nanoparticle-polyvinylpyrrolidone thin coatings with chemical structure close to that of the starting materials by MAPLE. • Thin film morphology studies revealed a uniform surface without aggregates or grains on the top of the surface. • MAPLE-deposited thin films exhibited antibacterial activity against Gram-positive and Gram-negative bacterial strains. • We demonstrated the potential use of these hybrid systems and MAPLE deposition method for the development of new harmless, ecological antimicrobial strategies. - Abstract: The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF * excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  9. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma & Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Visan, A.; Socol, G. [National Institute for Lasers, Plasma & Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Surdu, A.V.; Oprea, A.E.; Grumezescu, A.M. [Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, 1–7 Polizu Street, Bucharest, 011061 Romania (Romania); Chifiriuc, M.C. [Microbiology Immunology Department, Faculty of Biology, Research Institute of the University of Bucharest - ICUB, Bucharest, 77206 (Romania); Boehm, R.D.; Yamaleyeva, D.; Taylor, M.; Narayan, R.J. [Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC (United States); Chrisey, D.B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA (United States)

    2016-06-30

    Highlights: • We successfully deposited composite quercetin dehydrate-, resveratrol- and silver nanoparticle-polyvinylpyrrolidone thin coatings with chemical structure close to that of the starting materials by MAPLE. • Thin film morphology studies revealed a uniform surface without aggregates or grains on the top of the surface. • MAPLE-deposited thin films exhibited antibacterial activity against Gram-positive and Gram-negative bacterial strains. • We demonstrated the potential use of these hybrid systems and MAPLE deposition method for the development of new harmless, ecological antimicrobial strategies. - Abstract: The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF{sup *} excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  10. The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO3 percolative thin film

    International Nuclear Information System (INIS)

    Su, Yanbo; Hu, Tao; Tang, Liwen; Weng, Wenjian; Han, Gaorong; Ma, Ning; Du, Piyi

    2014-01-01

    Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO 3 (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti 4+ and Pb 2+ and CA coordinated with Ag + . Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag + was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO 3 percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles

  11. Laser-induced single point nanowelding of silver nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Shuowei; Li, Qiang, E-mail: qiangli@zju.edu.cn; Liu, Guoping; Yang, Hangbo; Yang, Yuanqing; Zhao, Ding; Wang, Wei; Qiu, Min, E-mail: minqiu@zju.edu.cn [State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-03-21

    Nanowelding of nanomaterials opens up an emerging set of applications in transparent conductors, thin-film solar cells, nanocatalysis, cancer therapy, and nanoscale patterning. Single point nanowelding (SPNW) is highly demanded for building complex nanostructures. In this letter, the precise control of SPNW of silver nanowires is explored in depth, where the nanowelding is laser-induced through the plasmonic resonance enhanced photothermal effect. It is shown that the illumination position is a critical factor for the nanowelding process. As an example of performance enhancement, output at wire end can be increased by 65% after welding for a plasmonic nanocoupler. Thus, single point nanowelding technique shows great potentials for high-performance electronic and photonic devices based on nanowires, such as nanoelectronic circuits and plasmonic nanodevices.

  12. Laser-induced single point nanowelding of silver nanowires

    International Nuclear Information System (INIS)

    Dai, Shuowei; Li, Qiang; Liu, Guoping; Yang, Hangbo; Yang, Yuanqing; Zhao, Ding; Wang, Wei; Qiu, Min

    2016-01-01

    Nanowelding of nanomaterials opens up an emerging set of applications in transparent conductors, thin-film solar cells, nanocatalysis, cancer therapy, and nanoscale patterning. Single point nanowelding (SPNW) is highly demanded for building complex nanostructures. In this letter, the precise control of SPNW of silver nanowires is explored in depth, where the nanowelding is laser-induced through the plasmonic resonance enhanced photothermal effect. It is shown that the illumination position is a critical factor for the nanowelding process. As an example of performance enhancement, output at wire end can be increased by 65% after welding for a plasmonic nanocoupler. Thus, single point nanowelding technique shows great potentials for high-performance electronic and photonic devices based on nanowires, such as nanoelectronic circuits and plasmonic nanodevices.

  13. Optical properties of silver sulphide thin films formed on evaporated Ag by a simple sulphurization method

    Energy Technology Data Exchange (ETDEWEB)

    Barrera-Calva, E., E-mail: ebc@xanum.uam.m [Departamento de Ingenieria de Procesos e hidraulica, Universidad Autonoma Metropolitana - Iztapalapa, Av. Purisima Esq. Michoacan, Col. Vicentina, Mexico, D.F., 09340 (Mexico); Ortega-Lopez, M.; Avila-Garcia, A.; Matsumoto-Kwabara, Y. [Departamento de Ingenieria Electrica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico DF 07360 (Mexico)

    2010-01-31

    Silver sulphide (Ag{sub 2}S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag{sub 2}S thin films display low intensity peaks at 34.48{sup o}, 36.56{sup o}, and 44.28{sup o}, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag{sub 2}S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag{sub 2}S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 {mu}m and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples.

  14. Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rebelo, Rita, E-mail: ritarebelo@det.uminho.pt [2C2T, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Manninen, N.K. [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal); Fialho, Luísa [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); Henriques, Mariana [CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Carvalho, Sandra [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal)

    2016-05-15

    Highlights: • Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering. • Coatings were characterized chemically, physically and structurally. • In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. • Ag{sub x}O coating presented antibacterial behavior. - Abstract: Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the Ag{sub x}O thin film showed both metallic Ag and Ag−O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while Ag{sub x}O layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and Ag{sub x}O surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to Ag{sub x}O coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology was

  15. Microstrain and residual stress in thin-films made from silver nanoparticles deposited by inkjet-printing technology

    NARCIS (Netherlands)

    Cauchois, R.; Borbély, A.; Gergaud, P.; Saadaoui, M.; Inal, K.

    2014-01-01

    Colloidal suspensions of nanoparticles are increasingly employed in the fabrication process of electronic devices using inkjet-printing technology and a consecutive thermal treatment. The evolution of internal stresses during the conversion of silver nanoparticle-based ink into a metallic thin-film

  16. Electroless silver plating of the surface of organic semiconductors.

    Science.gov (United States)

    Campione, Marcello; Parravicini, Matteo; Moret, Massimo; Papagni, Antonio; Schröter, Bernd; Fritz, Torsten

    2011-10-04

    The integration of nanoscale processes and devices demands fabrication routes involving rapid, cost-effective steps, preferably carried out under ambient conditions. The realization of the metal/organic semiconductor interface is one of the most demanding steps of device fabrication, since it requires mechanical and/or thermal treatments which increment costs and are often harmful in respect to the active layer. Here, we provide a microscopic analysis of a room temperature, electroless process aimed at the deposition of a nanostructured metallic silver layer with controlled coverage atop the surface of single crystals and thin films of organic semiconductors. This process relies on the reaction of aqueous AgF solutions with the nonwettable crystalline surface of donor-type organic semiconductors. It is observed that the formation of a uniform layer of silver nanoparticles can be accomplished within 20 min contact time. The electrical characterization of two-terminal devices performed before and after the aforementioned treatment shows that the metal deposition process is associated with a redox reaction causing the p-doping of the semiconductor. © 2011 American Chemical Society

  17. Inkjet-Printed Porous Silver Thin Film as a Cathode for a Low-Temperature Solid Oxide Fuel Cell.

    Science.gov (United States)

    Yu, Chen-Chiang; Baek, Jong Dae; Su, Chun-Hao; Fan, Liangdong; Wei, Jun; Liao, Ying-Chih; Su, Pei-Chen

    2016-04-27

    In this work we report a porous silver thin film cathode that was fabricated by a simple inkjet printing process for low-temperature solid oxide fuel cell applications. The electrochemical performance of the inkjet-printed silver cathode was studied at 300-450 °C and was compared with that of silver cathodes that were fabricated by the typical sputtering method. Inkjet-printed silver cathodes showed lower electrochemical impedance due to their porous structure, which facilitated oxygen gaseous diffusion and oxygen surface adsorption-dissociation reactions. A typical sputtered nanoporous silver cathode became essentially dense after the operation and showed high impedance due to a lack of oxygen supply. The results of long-term fuel cell operation show that the cell with an inkjet-printed cathode had a more stable current output for more than 45 h at 400 °C. A porous silver cathode is required for high fuel cell performance, and the simple inkjet printing technique offers an alternative method of fabrication for such a desirable porous structure with the required thermal-morphological stability.

  18. Studies on the electrical properties of reactive DC magnetron-sputtered indium-doped silver oxide thin films: The role of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, A [Semiconductor Physics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Barik, Ullash Kumar [Semiconductor Physics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2007-03-15

    Indium ({approx}10 at.%)-doped silver oxide (AIO) thin films have been prepared on glass substrates at room temperature (300 K) by reactive DC magnetron sputtering technique using an alloy target made of pure (99.99%) silver and indium (90:10 at.%) metals. The oxygen flow rates have been varied in the range 0.00-3.44 sccm during sputtering. The X-ray diffraction data on these indium-doped silver oxide films show polycrystalline nature. With increasing oxygen flow rate, the carrier concentration, the Hall mobility and the electron mean free path decrease. These films show a very low positive temperature coefficient of resistivity {approx}3.40x10{sup -8} ohm-cm/K. The work function values for these films (measured by Kelvin probe technique) are in the range 4.81-5.07 eV. The high electrical resistivity indicate that the films are in the island state (size effects). Calculations of the partial ionic charge (by Sanderson's theory) show that indium doping in silver oxide thin films enhance the ionicity.

  19. Studies on the electrical properties of reactive DC magnetron-sputtered indium-doped silver oxide thin films: The role of oxygen

    International Nuclear Information System (INIS)

    Subrahmanyam, A.; Barik, Ullash Kumar

    2007-01-01

    Indium (∼10 at.%)-doped silver oxide (AIO) thin films have been prepared on glass substrates at room temperature (300 K) by reactive DC magnetron sputtering technique using an alloy target made of pure (99.99%) silver and indium (90:10 at.%) metals. The oxygen flow rates have been varied in the range 0.00-3.44 sccm during sputtering. The X-ray diffraction data on these indium-doped silver oxide films show polycrystalline nature. With increasing oxygen flow rate, the carrier concentration, the Hall mobility and the electron mean free path decrease. These films show a very low positive temperature coefficient of resistivity ∼3.40x10 -8 ohm-cm/K. The work function values for these films (measured by Kelvin probe technique) are in the range 4.81-5.07 eV. The high electrical resistivity indicate that the films are in the island state (size effects). Calculations of the partial ionic charge (by Sanderson's theory) show that indium doping in silver oxide thin films enhance the ionicity

  20. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  1. The effect of a thin silver layer on the critical current of epitaxial YBCO films

    International Nuclear Information System (INIS)

    Polturak, E.; Koren, G.; Cohen, D.; Cohen, D.; Snapiro, I.

    1992-01-01

    We compare measurements of the critical current density of an epitaxial YBCO film with that of an identical film overlaid by a thin silver layer. We find that the presence of the silver lowers Tc of the film by about 1.5 K, which is two orders of magnitude larger than predicted by the theory of the proximity effect for our experimental conditions. In addition, J c of the Ag/YBCO film near Tc is also significantly lower than that of the bare YBCO film. We propose two alternate interpretations of this effect, one in terms of destabilization of the flux distribution in the film and the other making use of the effect of the silver on the Bean-Livingston surface barrier for the initial penetration of flux. The latter seems the more plausible explanation of our results. (orig.)

  2. Efficient electrochemical water oxidation in neutral and near-neutral systems by nanoscale silver-oxide catalyst

    KAUST Repository

    Joya, Khurram Saleem; Ahmad, Zahoor; Joya, Yasir Faheem; Garcia Esparza, Angel T.; de Groot, Huub

    2016-01-01

    In electrocatalytic water splitting systems pursuing for renewable energy using sun light, developing robust, stable and easy accessible materials operating under mild chemical conditions is pivotal. We present here unique nano-particulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3–/CO2 system under benign conditions. Mircographs show that they exhibit nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of > 1.1 mA cm–2 is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ions free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ions free electrolyte and tend to degrade with time and lose catalytic performance during long-term experimental tests.

  3. Efficient electrochemical water oxidation in neutral and near-neutral systems by nanoscale silver-oxide catalyst

    KAUST Repository

    Joya, Khurram Saleem

    2016-07-19

    In electrocatalytic water splitting systems pursuing for renewable energy using sun light, developing robust, stable and easy accessible materials operating under mild chemical conditions is pivotal. We present here unique nano-particulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3–/CO2 system under benign conditions. Mircographs show that they exhibit nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of > 1.1 mA cm–2 is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ions free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ions free electrolyte and tend to degrade with time and lose catalytic performance during long-term experimental tests.

  4. Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

    Science.gov (United States)

    Cristescu, R.; Visan, A.; Socol, G.; Surdu, A. V.; Oprea, A. E.; Grumezescu, A. M.; Chifiriuc, M. C.; Boehm, R. D.; Yamaleyeva, D.; Taylor, M.; Narayan, R. J.; Chrisey, D. B.

    2016-06-01

    The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF* excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

  5. Metal-enhanced fluorescence of mixed coumarin dyes by silver and gold nanoparticles: Towards plasmonic thin-film luminescent solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    El-Bashir, S.M., E-mail: elbashireg@yahoo.com [Department of Physics and Astronomy, Science College, King Saud University, Riyadh, KSA (Saudi Arabia); Department of Physics Faculty of Science, Benha University (Egypt); Barakat, F.M.; AlSalhi, M.S. [Department of Physics and Astronomy, Science College, King Saud University, Riyadh, KSA (Saudi Arabia)

    2013-11-15

    Poly(methyl methacrylate) (PMMA) nanocomposite films doped with mixed coumarin dyestuffs and noble metal nanoparticles (60 nm silver and 100 nm gold) were prepared by spin coating technique. The effect of silver and gold nanoparticles on the film properties was studied by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis absorption and fluorescence spectroscopy measurements. DSC measurements indicated the increase of the glass transition temperature of the films by increasing nanogold concentration, recommending their promising thermal stability towards hot climates. It was found that the fluorescence signals of the mixed coumarin dyes were amplified by 5.4 and 7.15 folds as a result of metal enhanced fluorescence (MEF). The research outcomes offered a potential application of these films in solar energy conversion by plasmonic thin film luminescent solar concentrator (PTLSC). -- Graphical abstract: Plasmonic thin film luminescent solar concentrators. Highlights: • Metal enhanced fluorescence was achieved for mixed coumarin dyes doped in PMMA nanocomposite films. • The amplification of the fluorescence signals is dependent on the concentration of silver and gold nanoparticles. • These films is considered as potential candidates for plasmonic thin film luminescent solar concentrators (PTLSCs)

  6. Quantifying resistances across nanoscale low- and high-angle interspherulite boundaries in solution-processed organic semiconductor thin films.

    Science.gov (United States)

    Lee, Stephanie S; Mativetsky, Jeffrey M; Loth, Marsha A; Anthony, John E; Loo, Yueh-Lin

    2012-11-27

    The nanoscale boundaries formed when neighboring spherulites impinge in polycrystalline, solution-processed organic semiconductor thin films act as bottlenecks to charge transport, significantly reducing organic thin-film transistor mobility in devices comprising spherulitic thin films as the active layers. These interspherulite boundaries (ISBs) are structurally complex, with varying angles of molecular orientation mismatch along their lengths. We have successfully engineered exclusively low- and exclusively high-angle ISBs to elucidate how the angle of molecular orientation mismatch at ISBs affects their resistivities in triethylsilylethynyl anthradithiophene thin films. Conductive AFM and four-probe measurements reveal that current flow is unaffected by the presence of low-angle ISBs, whereas current flow is significantly disrupted across high-angle ISBs. In the latter case, we estimate the resistivity to be 22 MΩμm(2)/width of the ISB, only less than a quarter of the resistivity measured across low-angle grain boundaries in thermally evaporated sexithiophene thin films. This discrepancy in resistivities across ISBs in solution-processed organic semiconductor thin films and grain boundaries in thermally evaporated organic semiconductor thin films likely arises from inherent differences in the nature of film formation in the respective systems.

  7. Grain growth: The key to understand solid-state dewetting of silver thin films

    International Nuclear Information System (INIS)

    Jacquet, P.; Podor, R.; Ravaux, J.; Teisseire, J.; Gozhyk, I.; Jupille, J.; Lazzari, R.

    2016-01-01

    The dynamics of solid-state dewetting of polycrystalline silver thin films in oxygen atmosphere was investigated with in situ and real-time environmental Scanning Electron Microscopy at high temperature combined with Atomic Force Microscopy. Three steps were identified during dewetting: induction, hole propagation without specific rim and sintering. Moreover, it was observed that a very selective grain growth, promoted by surface diffusion, plays a key role all along the process.

  8. Lithographically patterned electrodeposition of gold, silver, and nickel nanoring arrays with widely tunable near-infrared plasmonic resonances.

    Science.gov (United States)

    Halpern, Aaron R; Corn, Robert M

    2013-02-26

    A novel low-cost nanoring array fabrication method that combines the process of lithographically patterned nanoscale electrodeposition (LPNE) with colloidal lithography is described. Nanoring array fabrication was accomplished in three steps: (i) a thin (70 nm) sacrificial nickel or silver film was first vapor-deposited onto a plasma-etched packed colloidal monolayer; (ii) the polymer colloids were removed from the surface, a thin film of positive photoresist was applied, and a backside exposure of the photoresist was used to create a nanohole electrode array; (iii) this array of nanoscale cylindrical electrodes was then used for the electrodeposition of gold, silver, or nickel nanorings. Removal of the photoresist and sacrificial metal film yielded a nanoring array in which all of the nanoring dimensions were set independently: the inter-ring spacing was fixed by the colloidal radius, the radius of the nanorings was controlled by the plasma etching process, and the width of the nanorings was controlled by the electrodeposition process. A combination of scanning electron microscopy (SEM) measurements and Fourier transform near-infrared (FT-NIR) absorption spectroscopy were used to characterize the nanoring arrays. Nanoring arrays with radii from 200 to 400 nm exhibited a single strong NIR plasmonic resonance with an absorption maximum wavelength that varied linearly from 1.25 to 3.33 μm as predicted by a simple standing wave model linear antenna theory. This simple yet versatile nanoring array fabrication method was also used to electrodeposit concentric double gold nanoring arrays that exhibited multiple NIR plasmonic resonances.

  9. Thin and long silver nanowires self-assembled in ionic liquids as a soft template: electrical and optical properties.

    Science.gov (United States)

    Chang, Min-Hwa; Cho, Hyun-Ah; Kim, Youn-Soo; Lee, Eun-Jong; Kim, Jin-Yeol

    2014-01-01

    Thin and long silver nanowires were successfully synthesized using the polyvinylpyrrolidone (PVP)-assisted polyol method in the presence of ionic liquids, tetrapropylammonium chloride and tetrapropylammonium bromide, which served as soft template salts. The first step involved the formation of Ag nanoparticles with a diameter of 40 to 50 nm through the reduction of silver nitrate. At the growing stage, the Ag nanoparticles were converted into thin and long one-dimensional wires, with uniform diameters of 30 ± 3 nm and lengths of up to 50 μm. These Ag nanowires showed an electrical conductivity of 0.3 × 10(5) S/cm, while the sheet resistance of a two-dimensional percolating Ag nanowire network exhibited a value of 20 Ω/sq with an optical transmittance of 93% and a low haze value.

  10. Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

    Directory of Open Access Journals (Sweden)

    Mirosław Gierczak

    2018-01-01

    Full Text Available This paper describes the design, manufacturing and characterization of newly developed mixed thick-/thin film thermoelectric microgenerators based on magnetron sputtered constantan (copper-nickel alloy and screen-printed silver layers. The thermoelectric microgenerator consists of sixteen thermocouples made on a 34.2 × 27.5 × 0.25 mm3 alumina substrate. One of thermocouple arms was made of magnetron-sputtered constantan (Cu-Ni alloy, the second was a Ag-based screen-printed film. The length of each thermocouple arm was equal to 27 mm, and their width 0.3 mm. The distance between the arms was equal to 0.3 mm. In the first step, a pattern mask with thermocouples was designed and fabricated. Then, a constantan layer was magnetron sputtered over the whole substrate, and a photolithography process was used to prepare the first thermocouple arms. The second arms were screen-printed onto the substrate using a low-temperature silver paste (Heraeus C8829A or ElectroScience Laboratories ESL 599-E. To avoid oxidation of constantan, they were fired in a belt furnace in a nitrogen atmosphere at 550/450 °C peak firing temperature. Thermoelectric and electrical measurements were performed using the self-made measuring system. Two pyrometers included into the system were used for temperature measurement of hot and cold junctions. The estimated Seebeck coefficient, α was from the range 35 − 41 µV/K, whereas the total internal resistances R were between 250 and 3200 ohms, depending on magnetron sputtering time and kind of silver ink (the resistance of a single thermocouple was between 15.5 and 200 ohms.

  11. Nanoscale Thermoelectrics: A Study of the Absolute Seebeck Coefficient of Thin Films

    Science.gov (United States)

    Mason, Sarah J.

    The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric devices have the ability to generate clean, renewable, energy out of waste heat. However promising that is, their inefficiency severely inhibits applicability and practical use. The usefulness of a thermoelectric material increases with the dimensionless quantity, ZT, which depends on the Seebeck coefficient and electrical and thermal conductivity. These characteristic material parameters have interdependent energy transport contributions that classically prohibit the optimization of one with out the detriment of another. Encouraging advancements of ZT have occurred in the past ten years due to the decoupling of the thermal and electrical conductivity. Further advancements are necessary in order to produce applicable devices. One auspicious way of decoupling or tuning energy transport properties, is through size reduction to the nanoscale. However, with reduced dimensions come complications in measuring material properties. Measurements of properties such as the Seebeck coefficient, S, are primarily contingent upon the measurement apparatus. The Seebeck coefficient is defined as the amount of voltage generated by a thermal gradient. Measuring a thermally generated voltage by traditional methods gives, the voltage measured as a linear function of the Seebeck coefficient of the leads and of the material being tested divided by the applied thermal gradient. If accurate values of the Seebeck coefficients of the leads are available, simple subtraction provides the answer. This is rarely the case in nanoscale measurement devices with leads exclusively made from thin film materials that do not have well known bulk-like thermopower values. We have developed a technique to directly

  12. Nanoscale strengthening mechanisms in metallic thin film systems

    Science.gov (United States)

    Schoeppner, Rachel Lynn

    Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity

  13. Electrical and optical properties of reactive dc magnetron sputtered silver-doped indium oxide thin films: role of oxygen

    International Nuclear Information System (INIS)

    Subrahmanyam, A.; Barik, U.K.

    2006-01-01

    Silver-doped indium oxide thin films have been prepared on glass and quartz substrates at room temperature (300 K) by a reactive dc magnetron sputtering technique using an alloy target of pure indium and silver (80:20 at. %). During sputtering, the oxygen flow rates are varied in the range 0.00-2.86 sccm keeping the magnetron power constant at 40 W. The resistivity of these films is in the range 10 0 -10 -3 Ωcm and they show a negative temperature coefficient of resistivity. The films exhibit p-type conductivity at an oxygen flow rate of 1.71 sccm. The work function of these silver-indium oxide films has been measured by a Kelvin probe technique. The refractive index of the films (at 632.8 nm) varies in the range 1.13-1.20. Silver doping in indium oxide narrows the band gap of indium oxide (3.75 eV). (orig.)

  14. Electrical and optical properties of reactive dc magnetron sputtered silver-doped indium oxide thin films: role of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, A; Barik, U K [Indian Institute of Technology Madras, Semiconductor Physics Laboratory, Department of Physics, Chennai (India)

    2006-07-15

    Silver-doped indium oxide thin films have been prepared on glass and quartz substrates at room temperature (300 K) by a reactive dc magnetron sputtering technique using an alloy target of pure indium and silver (80:20 at. %). During sputtering, the oxygen flow rates are varied in the range 0.00-2.86 sccm keeping the magnetron power constant at 40 W. The resistivity of these films is in the range 10{sup 0}-10{sup -3} {omega}cm and they show a negative temperature coefficient of resistivity. The films exhibit p-type conductivity at an oxygen flow rate of 1.71 sccm. The work function of these silver-indium oxide films has been measured by a Kelvin probe technique. The refractive index of the films (at 632.8 nm) varies in the range 1.13-1.20. Silver doping in indium oxide narrows the band gap of indium oxide (3.75 eV). (orig.)

  15. The production of ultra-thin layers of ion-exchange resin and metallic silver by electrospraying

    International Nuclear Information System (INIS)

    Wyllie, H.A.

    1988-10-01

    Highly efficient radioactive sources for use in radioisotope metrology have been prepared on ultra-thin layers of electrosprayed ion-exchange resin. The efficiency of these sources can be reduced for the purpose of radioactivity standardisation by coating them with conducting silver layers which are also produced by electrospraying. A description is given of improvements to the electrospraying methods, together with details of the rotating, oscillating source-mount turntable

  16. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films

    International Nuclear Information System (INIS)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A.

    2011-01-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  17. Multispectral surface plasmon resonance approach for ultra-thin silver layer characterization: Application to top-emitting OLED cathode

    Science.gov (United States)

    Taverne, S.; Caron, B.; Gétin, S.; Lartigue, O.; Lopez, C.; Meunier-Della-Gatta, S.; Gorge, V.; Reymermier, M.; Racine, B.; Maindron, T.; Quesnel, E.

    2018-01-01

    While dielectric/metal/dielectric (DMD) multilayer thin films have raised considerable interest as transparent and conductive electrodes in various optoelectronic devices, the knowledge of optical characteristics of thin metallic layers integrated in such structures is still rather approximate. The multispectral surface plasmon resonance characterization approach described in this work precisely aims at providing a rigorous methodology able to accurately determine the optical constants of ultra-thin metallic films. As a practical example, the refractive index and extinction dispersion curves of 8 to 25 nm-thick silver layers have been investigated. As a result, their extreme dependence on the layer thickness is highlighted, in particular in a thickness range close to the critical threshold value (˜10 nm) where the silver film becomes continuous and its electrical conductance/optical transmittance ratio particularly interesting. To check the validity of the revisited Ag layers constant dispersion curves deduced from this study, they were introduced into a commercial optical model software to simulate the behavior of various optoelectronic building blocks from the simplest ones (DMD electrodes) to much more complex structures [full organic light emitting device (OLED) stacks]. As a result, a much better prediction of the emission spectrum profile as well as the angular emission pattern of top-emitting OLEDs is obtained. On this basis, it is also shown how a redesign of the top encapsulation thin film of OLEDs is necessary to better take benefit from the advanced DMD electrode. These results should particularly interest the micro-OLED display field where bright and directive single color pixel emission is required.

  18. Antimicrobial activity of thin metallic silver flakes, waste products of a manufacturing process.

    Science.gov (United States)

    Anzano, Manuela; Tosti, Alessandra; Lasagni, Marina; Campiglio, Alfredo; Pitea, Demetrio; Collina, Elena

    2011-01-01

    The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company. The company produced thin silver metallic films and the production scraps were silver flakes. The possibility to use the silver flakes in water disinfection processes was studied. The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model. The flakes did not show any antimicrobial activity, so they were activated with two different processes: thermal activation in reducing atmosphere and chemical activation, obtaining, respectively, reduced flakes (RF) and chemical flakes (CF). The flakes, activated with either treatment, showed antimicrobial activity against E. coli. The kill rate was dependent on the type of activated flakes. The chemical flakes were more efficient than reduced flakes. The kill rate determined for 1 g of CF, 1.0 +/- 0.2 min(-1), was greater than the kill rate determined for 1 g of RF, 0.069 +/- 0.004 min(-1). This was confirmed also by the minimum inhibitory concentration values. It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium. Furthermore, the flakes maintained their properties also when used a second time. Finally, the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.

  19. Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

    International Nuclear Information System (INIS)

    Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

    2012-01-01

    For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag + } in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2–30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag + } values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO 3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag + } ≤ 9.2.

  20. Silver powder effectiveness and mechanism of silver paste on silicon solar cells

    International Nuclear Information System (INIS)

    Tsai, Jung-Ting; Lin, Shun-Tian

    2013-01-01

    Highlights: ► Optimizing the silver paste in 80–85 wt.%. ► Optimizing its particle size in 1–1.5 μm spherical powder. ► The sheet resistance is 4 mΩ/sq during the 860 °C sintering process. ► Redox reaction cause Ag crystallites to grow on the interface. ► A thin layer of silicon oxide (75–150 nm) was formed. - Abstract: Since the silver paste plays a major role in the mass production of silicon solar cells, this work has succeeded in optimizing the silver paste in 80–85 wt.% and optimizing its particle size in 1–1.5 μm spherical powder. As the firing temperature is increased, the growth trend of silver grain is improved. The result of this work has showed that the lowest sheet resistance is 4 mΩ/sq during the 860 °C sintering process. The scanning electron microscope (SEM) observation has showed that the formation of silver oxide is formed during the melting process of glass and triggered redox reaction of Ag crystallites to grow on the interface. It has proven by transmission electron microscope (TEM) that a thin layer of silicon oxide (75–150 nm) was formed, respectively.

  1. Optical properties of silver composite metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Orbons, S.M. [School of Physics, University of Melbourne, Victoria 3010 (Australia)]. E-mail: sorbons@ph.unimelb.edu.au; Freeman, D. [Centre for Ultrahigh-bandwidth Devices for Optical Systems, Laser Physics Centre, Australian National University, ACT 0200 (Australia); Luther-Davies, B. [Centre for Ultrahigh-bandwidth Devices for Optical Systems, Laser Physics Centre, Australian National University, ACT 0200 (Australia); Gibson, B.C. [Quantum Communications Victoria, School of Physics, University of Melbourne, Victoria 3010 (Australia); Huntington, S.T. [Quantum Communications Victoria, School of Physics, University of Melbourne, Victoria 3010 (Australia); Jamieson, D.N. [School of Physics, University of Melbourne, Victoria 3010 (Australia); Roberts, A. [School of Physics, University of Melbourne, Victoria 3010 (Australia)

    2007-05-15

    We present a computational and experimental study investigating the optical properties of nanoscale silver composite metamaterials fabricated by ion beam lithography. Both simulations and experimental results demonstrate high transmission efficiencies in the near infra-red through these devices. Implications for experimentally verifying the calculated near-field distributions of these materials are also discussed.

  2. Relative SHG measurements of metal thin films: Gold, silver, aluminum, cobalt, chromium, germanium, nickel, antimony, titanium, titanium nitride, tungsten, zinc, silicon and indium tin oxide

    Directory of Open Access Journals (Sweden)

    Franklin Che

    Full Text Available We have experimentally measured the surface second-harmonic generation (SHG of sputtered gold, silver, aluminum, zinc, tungsten, copper, titanium, cobalt, nickel, chromium, germanium, antimony, titanium nitride, silicon and indium tin oxide thin films. The second-harmonic response was measured in reflection using a 150 fs p-polarized laser pulse at 1561 nm. We present a clear comparison of the SHG intensity of these films relative to each other. Our measured relative intensities compare favorably with the relative intensities of metals with published data. We also report for the first time to our knowledge the surface SHG intensity of tungsten and antimony relative to that of well known metallic thin films such as gold and silver. Keywords: Surface second-harmonic generation, Nonlinear optics, Metal thin films

  3. Laser beam induced nanoscale spot through nonlinear “thick” samples: A multi-layer thin lens self-focusing model

    International Nuclear Information System (INIS)

    Wei, Jingsong; Yan, Hui

    2014-01-01

    Self-focusing is a well-researched phenomenon. Nanoscale spots can be achieved through self-focusing, which is an alternative method for achieving high-density data storage, high-resolution light imaging, and maskless nanolithography. Several research groups have observed that self-focusing spots can be reduced to nanoscale levels via incident laser power manipulation. Self-focusing spots can be analyzed by solving the nonlinear Schrödinger equation and the finite difference time domain method. However, both procedures are complex and time-consuming. In the present work, a multi-layer thin-lens self-focusing model that considers diffraction effects and changes of refractive index along the radial and film thickness directions is proposed to analyze the self-focusing behavior and traveling process of light beams intuitively. The self-focusing behaviors of As 2 S 3 are simulated, and results show that a nanoscale self-focusing spot with a radius of about 0.12 μm can be formed at the bottom of nonlinear sample when the incident laser power exceeds 4.25 mW. Our findings are basically consistent with experimental reports and provide a good method for analyzing and understanding the self-focusing process. An appropriate application schematic design is also provided

  4. Nanoscale thermal-mechanical probe determination of 'softening transitions' in thin polymer films

    International Nuclear Information System (INIS)

    Zhou Jing; Berry, Brian; Douglas, Jack F; Karim, Alamgir; Snyder, Chad R; Soles, Christopher

    2008-01-01

    We report a quantitative study of the softening behavior of glassy polystyrene (PS) films at length scales on the order of 100 nm using nano-thermomechanometry (nano-TM), an emerging scanning probe technique in which a highly doped silicon atomic force microscopy (AFM) tip is resistively heated on the surface of a polymer film. The apparent 'softening temperature' T s of the film is found to depend on the logarithm of the square root of the thermal ramping rate R. This relation allows us to estimate a quasi-equilibrium (or zero rate) softening transition temperature T s0 by extrapolation. We observe marked shifts of T s0 with decreasing film thickness, but the nature of these shifts, and even their sign, depend strongly on both the thermal and mechanical properties of the supporting substrate. Finite element simulations suggest that thin PS films on rigid substrates with large thermal conductivities lead to increasing T s0 with decreasing film thickness, whereas softer, less thermally conductive substrates promote reductions in T s0 . Experimental observations on a range of substrates confirm this behavior and indicate a complicated interplay between the thermal and mechanical properties of the thin PS film and the substrate. This study directly points to relevant factors for quantitative measurements of thermophysical properties of materials at the nanoscale using this nano-TM based method.

  5. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    Science.gov (United States)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ˜1.78eV with high absorption coefficient ˜106/m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80-330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ˜2.6Ωm and the films showed good photo response.

  6. Nanoscale current spreading analysis in solution-processed graphene oxide/silver nanowire transparent electrodes via conductive atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Joseph E.; Perumal, Ajay; Bradley, Donal D. C.; Stavrinou, Paul N.; Anthopoulos, Thomas D., E-mail: t.anthopoulos@ic.ac.uk [Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

    2016-05-21

    We use conductive atomic force microscopy (CAFM) to study the origin of long-range conductivity in model transparent conductive electrodes composed of networks of reduced graphene oxide (rGO{sub X}) and silver nanowires (AgNWs), with nanoscale spatial resolution. Pristine networks of rGO{sub X} (1–3 monolayers-thick) and AgNWs exhibit sheet resistances of ∼100–1000 kΩ/□ and 100–900 Ω/□, respectively. When the materials are deposited sequentially to form bilayer rGO{sub X}/AgNW electrodes and thermally annealed at 200 °C, the sheet resistance reduces by up to 36% as compared to pristine AgNW networks. CAFM was used to analyze the current spreading in both systems in order to identify the nanoscale phenomena responsible for this effect. For rGO{sub X} networks, the low intra-flake conductivity and the inter-flake contact resistance is found to dominate the macroscopic sheet resistance, while for AgNW networks the latter is determined by the density of the inter-AgNW junctions and their associated resistance. In the case of the bilayer rGO{sub X}/AgNWs' networks, rGO{sub X} flakes are found to form conductive “bridges” between AgNWs. We show that these additional nanoscopic electrical connections are responsible for the enhanced macroscopic conductivity of the bilayer rGO{sub X}/AgNW electrodes. Finally, the critical role of thermal annealing on the formation of these nanoscopic connections is discussed.

  7. Nanotribological Behavior of Carbon Based Thin Films: Friction and Lubricity Mechanisms at the Nanoscale

    Directory of Open Access Journals (Sweden)

    Costas A. Charitidis

    2013-04-01

    Full Text Available The use of materials with very attractive friction and wear properties has raised much attention in research and industrial sectors. A wide range of tribological applications, including rolling and sliding bearings, machining, mechanical seals, biomedical implants and microelectromechanical systems (MEMS, require thin films with high mechanical strength, chemical inertness, broad optical transparency, high refractive index, wide bandgap excellent thermal conductivity and extremely low thermal expansion. Carbon based thin films like diamond, diamond-like carbon, carbon nitride and cubic boron nitride known as “super-hard” material have been studied thoroughly as the ideal candidate for tribological applications. In this study, the results of experimental and simulation works on the nanotribological behavior of carbon films and fundamental mechanisms of friction and lubricity at the nano-scale are reviewed. The study is focused on the nanomechanical properties and analysis of the nanoscratching processes at low loads to obtain quantitative analysis, the comparison obtain quantitative analysis, the comparison of their elastic/plastic deformation response, and nanotribological behavior of the a-C, ta-C, a-C:H, CNx, and a-C:M films. For ta-C and a-C:M films new data are presented and discussed.

  8. Antimicrobial Properties of Diamond-Like Carbon/Silver Nanocomposite Thin Films Deposited on Textiles: Towards Smart Bandages

    Directory of Open Access Journals (Sweden)

    Tadas Juknius

    2016-05-01

    Full Text Available In the current work, a new antibacterial bandage was proposed where diamond-like carbon with silver nanoparticle (DLC:Ag-coated synthetic silk tissue was used as a building block. The DLC:Ag structure, the dimensions of nanoparticles, the silver concentration and the silver ion release were studied systematically employing scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic absorption spectroscopy, respectively. Antimicrobial properties were investigated using microbiological tests (disk diffusion method and spread-plate technique. The DLC:Ag layer was stabilized on the surface of the bandage using a thin layer of medical grade gelatin and cellulose. Four different strains of Staphylococcus aureus extracted from humans’ and animals’ infected wounds were used. It is demonstrated that the efficiency of the Ag+ ion release to the aqueous media can be increased by further RF oxygen plasma etching of the nanocomposite. It was obtained that the best antibacterial properties were demonstrated by the plasma-processed DLC:Ag layer having a 3.12 at % Ag surface concentration with the dominating linear dimensions of nanoparticles being 23.7 nm. An extra protective layer made from cellulose and gelatin with agar contributed to the accumulation and efficient release of silver ions to the aqueous media, increasing bandage antimicrobial efficiency up to 50% as compared to the single DLC:Ag layer on textile.

  9. Antimicrobial Properties of Diamond-Like Carbon/Silver Nanocomposite Thin Films Deposited on Textiles: Towards Smart Bandages

    Science.gov (United States)

    Juknius, Tadas; Ružauskas, Modestas; Tamulevičius, Tomas; Šiugždinienė, Rita; Juknienė, Indrė; Vasiliauskas, Andrius; Jurkevičiūtė, Aušrinė; Tamulevičius, Sigitas

    2016-01-01

    In the current work, a new antibacterial bandage was proposed where diamond-like carbon with silver nanoparticle (DLC:Ag)-coated synthetic silk tissue was used as a building block. The DLC:Ag structure, the dimensions of nanoparticles, the silver concentration and the silver ion release were studied systematically employing scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic absorption spectroscopy, respectively. Antimicrobial properties were investigated using microbiological tests (disk diffusion method and spread-plate technique). The DLC:Ag layer was stabilized on the surface of the bandage using a thin layer of medical grade gelatin and cellulose. Four different strains of Staphylococcus aureus extracted from humans’ and animals’ infected wounds were used. It is demonstrated that the efficiency of the Ag+ ion release to the aqueous media can be increased by further RF oxygen plasma etching of the nanocomposite. It was obtained that the best antibacterial properties were demonstrated by the plasma-processed DLC:Ag layer having a 3.12 at % Ag surface concentration with the dominating linear dimensions of nanoparticles being 23.7 nm. An extra protective layer made from cellulose and gelatin with agar contributed to the accumulation and efficient release of silver ions to the aqueous media, increasing bandage antimicrobial efficiency up to 50% as compared to the single DLC:Ag layer on textile. PMID:28773494

  10. Antibacterial Properties of Titanate Nano fiber Thin Films Formed on a Titanium Plate

    International Nuclear Information System (INIS)

    Yada, M.; Inoue, Y.; Morita, T.; Torikai, T.; Watari, T.; Noda, I.; Hotokebuchi, T.

    2013-01-01

    A sodium titanate nano fiber thin film and a silver nanoparticle/silver titanate nano fiber thin film formed on the surface of a titanium plate exhibited strong antibacterial activities against methicillin-resistant Staphylococcus aureus, which is one of the major bacteria causing in-hospital infections. Exposure of the sodium titanate nano fiber thin film to ultraviolet rays generated a high antibacterial activity due to photo catalysis and the sodium titanate nano fiber thin film immediately after its synthesis possessed a high antibacterial activity even without exposure to ultraviolet rays. Elution of silver from the silver nanoparticle/silver titanate nano fiber thin film caused by the silver ion exchange reaction was considered to contribute substantially to the strong antibacterial activity. The titanate nano fiber thin films adhered firmly to titanium. Therefore, these titanate nano fiber thin film/titanium composites will be extremely useful as implant materials that have excellent antibacterial activities.

  11. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    International Nuclear Information System (INIS)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ∼1.78eV with high absorption coefficient ∼10 6 /m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80–330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ∼2.6Ωm and the films showed good photo response

  12. Nanoscale Ferroelectric Switchable Polarization and Leakage Current Behavior in (Ba0.50Sr0.50(Ti0.80Sn0.20O3 Thin Films Prepared Using Chemical Solution Deposition

    Directory of Open Access Journals (Sweden)

    Venkata Sreenivas Puli

    2015-01-01

    Full Text Available Nanoscale switchable ferroelectric (Ba0.50Sr0.50(Ti0.80Sn0.20O3-BSTS polycrystalline thin films with a perovskite structure were prepared on Pt/TiOx/SiO2/Si substrate by chemical solution deposition. X-ray diffraction (XRD spectra indicate that a cubic perovskite crystalline structure and Raman spectra revealed that a tetragonal perovskite crystalline structure is present in the thin films. Sr2+ and Sn4+ cosubstituted film exhibited the lowest leakage current density. Piezoresponse Force Microscopy (PFM technique has been employed to acquire out-of-plane (OPP piezoresponse images and local piezoelectric hysteresis loop in polycrystalline BSTS films. PFM phase and amplitude images reveal nanoscale ferroelectric switching behavior at room temperature. Square patterns with dark and bright contrasts were written by local poling and reversible nature of the piezoresponse behavior was established. Local piezoelectric butterfly amplitude and phase hysteresis loops display ferroelectric nature at nanoscale level. The significance of this paper is to present ferroelectric/piezoelectric nature in present BSTS films at nanoscale level and corroborating ferroelectric behavior by utilizing Raman spectroscopy. Thus, further optimizing physical and electrical properties, BSTS films might be useful for practical applications which include nonvolatile ferroelectric memories, data-storage media, piezoelectric actuators, and electric energy storage capacitors.

  13. Plasmon enhanced silver quantum cluster fluorescence for biochemical applications

    DEFF Research Database (Denmark)

    Bernard, S.; Kutter, J.P.; Mogensen, Klaus Bo

    2014-01-01

    Fluorescence microscopy of individual silver quantum clusters on the surface of silver nanoparticles reveals strong photoactivated emission under blue light excitation [1-4]. In this work, silver nanoparticles are produced by annealing silver thin films deposited on a glass substrate and silver q...... purposes. It was found, that in presence of a strong nucleophile (such as CN-), silver quantum clusters are dissolved into non-fluorescing AgCN complexes, resulting in a fast and observable decrease of the fluorescent signal....

  14. Photochemical oxygen reduction by zinc phthalocyanine and silver/gold nanoparticle incorporated silica thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Manas; Ganesan, Vellaichamy, E-mail: velganesh@yahoo.com; Azad, Uday Pratap

    2012-12-15

    Silver or gold nanoparticles are synthesized using a borohydride reduction method and are anchored simultaneously into/onto the mercaptopropyl functionalized silica. Later, zinc phthalocyanine is adsorbed onto the above materials. Thin films of these materials are prepared by coating an aqueous colloidal suspension of the respective material onto glass plates. Visible light irradiation of these films in oxygen saturated, stirred aqueous solutions effectively reduces oxygen to hydrogen peroxide. The photocatalytic reduction of oxygen is explained on the basis of the semiconducting properties of the silica films. The back electron transfer reaction is largely prevented by means of a sacrificial electron donor, triethanolamine. - Highlights: Black-Right-Pointing-Pointer Zinc phthalocyanine adsorbed silica materials were prepared. Black-Right-Pointing-Pointer Thin films of these materials photocatalytically reduce oxygen. Black-Right-Pointing-Pointer The photocatalysis is explained based on semiconductor properties of the materials. Black-Right-Pointing-Pointer Metal nanoparticles increase the photocatalytic efficiency of the materials.

  15. Silver-Stained Fibrin Zymography: Separation of Proteases and Activity Detection Using a Single Substrate-Containing Gel.

    Science.gov (United States)

    Park, Chang-Su; Kang, Dae-Ook; Choi, Nack-Shick

    2017-01-01

    Silver-stained fibrin zymography for separation of protease bands and activity detection using a single substrate gel was designed. The method takes advantage of the nano-scale sensitivity of both zymography and silver staining. After sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) in a gel containing fibrin (protease substrate), the gel was incubated in enzyme reaction buffer and the zymogram gel was silver-stained. Bands with protease activity were stained with silver in clear areas where the protein substrate had been degraded. The molecular sizes of proteases were accurately determined.

  16. Atomically precise arrays of fluorescent silver clusters: a modular approach for metal cluster photonics on DNA nanostructures.

    Science.gov (United States)

    Copp, Stacy M; Schultz, Danielle E; Swasey, Steven; Gwinn, Elisabeth G

    2015-03-24

    The remarkable precision that DNA scaffolds provide for arraying nanoscale optical elements enables optical phenomena that arise from interactions of metal nanoparticles, dye molecules, and quantum dots placed at nanoscale separations. However, control of ensemble optical properties has been limited by the difficulty of achieving uniform particle sizes and shapes. Ligand-stabilized metal clusters offer a route to atomically precise arrays that combine desirable attributes of both metals and molecules. Exploiting the unique advantages of the cluster regime requires techniques to realize controlled nanoscale placement of select cluster structures. Here we show that atomically monodisperse arrays of fluorescent, DNA-stabilized silver clusters can be realized on a prototypical scaffold, a DNA nanotube, with attachment sites separated by <10 nm. Cluster attachment is mediated by designed DNA linkers that enable isolation of specific clusters prior to assembly on nanotubes and preserve cluster structure and spectral purity after assembly. The modularity of this approach generalizes to silver clusters of diverse sizes and DNA scaffolds of many types. Thus, these silver cluster nano-optical elements, which themselves have colors selected by their particular DNA templating oligomer, bring unique dimensions of control and flexibility to the rapidly expanding field of nano-optics.

  17. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lyutakov, O., E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Goncharova, I. [Department of Analytical Chemistry, Institute of Chemical Technology, Prague (Czech Republic); Rimpelova, S. [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague (Czech Republic); Kolarova, K.; Svanda, J.; Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic)

    2015-04-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag{sup +} had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag{sup +} doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching.

  18. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    International Nuclear Information System (INIS)

    Lyutakov, O.; Goncharova, I.; Rimpelova, S.; Kolarova, K.; Svanda, J.; Svorcik, V.

    2015-01-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag + had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag + doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching

  19. Enhanced nanoscale friction on fluorinated graphene.

    Science.gov (United States)

    Kwon, Sangku; Ko, Jae-Hyeon; Jeon, Ki-Joon; Kim, Yong-Hyun; Park, Jeong Young

    2012-12-12

    Atomically thin graphene is an ideal model system for studying nanoscale friction due to its intrinsic two-dimensional (2D) anisotropy. Furthermore, modulating its tribological properties could be an important milestone for graphene-based micro- and nanomechanical devices. Here, we report unexpectedly enhanced nanoscale friction on chemically modified graphene and a relevant theoretical analysis associated with flexural phonons. Ultrahigh vacuum friction force microscopy measurements show that nanoscale friction on the graphene surface increases by a factor of 6 after fluorination of the surface, while the adhesion force is slightly reduced. Density functional theory calculations show that the out-of-plane bending stiffness of graphene increases up to 4-fold after fluorination. Thus, the less compliant F-graphene exhibits more friction. This indicates that the mechanics of tip-to-graphene nanoscale friction would be characteristically different from that of conventional solid-on-solid contact and would be dominated by the out-of-plane bending stiffness of the chemically modified graphene. We propose that damping via flexural phonons could be a main source for frictional energy dissipation in 2D systems such as graphene.

  20. Graphene coatings for chemotherapy: avoiding silver-mediated degradation

    International Nuclear Information System (INIS)

    Mazzola, Federico; Cooil, Simon; Skjønsfjell, Eirik Torbjørn Bakken; Breiby, Dag W; Wells, Justin W; Trinh, Thuat; Kjelstrup, Signe; Østli, Elise Ramleth; Høydalsvik, Kristin; Preobrajenski, Alexei; Cafolla, Attilio A; Evans, D Andrew

    2015-01-01

    Chemotherapy treatment usually involves the delivery of fluorouracil (5-Fu) together with other drugs through central venous catheters. Catheters and their connectors are increasingly treated with silver or argentic alloys/compounds. Complications arising from broken catheters are common, leading to additional suffering for patients and increased medical costs. Here, we uncover a likely cause of such failure through a study of the surface chemistry relevant to chemotherapy drug delivery, i.e. between 5-Fu and silver. We show that silver catalytically decomposes 5-Fu, compromising the efficacy of the chemotherapy treatment. Furthermore, HF is released as a product, which will be damaging to both patient and catheter. We demonstrate that graphene surfaces inhibit this undesirable reaction and would offer superior performance as nanoscale coatings in cancer treatment applications. (paper)

  1. DC magnetron sputtering prepared Ag-C thin film anode for thin film lithium ion microbatteries

    International Nuclear Information System (INIS)

    Li, Y.; Tu, J.P.; Shi, D.Q.; Huang, X.H.; Wu, H.M.; Yuan, Y.F.; Zhao, X.B.

    2007-01-01

    An Ag-C thin film was prepared by DC magnetron co-sputtering, using pure silver and graphite as the targets. The microstructure and morphology of the deposited thin film were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical performances of the Ag-C thin film anode were investigated by means of discharge/charge and cyclic voltammogram (CV) tests in model cells. The electrochemical impedance spectrum (EIS) characteristics and the chemical diffusion coefficient, D Li of the Ag-C thin film electrode at different discharging states were discussed. It was believed that the excellent cycling performance of the Ag-C electrode was ascribed to the good conductivity of silver and the volume stability of the thin film

  2. Evaluation of diffusion barrier and electrical properties of tantalum oxynitride thin films for silver metallization

    International Nuclear Information System (INIS)

    Misra, E.; Wang, Y.; Theodore, N.D.; Alford, T.L.

    2004-01-01

    The thermal stability and the diffusion barrier properties of DC reactively sputtered tantalum oxynitride (Ta-O-N) thin films, between silver (Ag) and silicon (Si) p + n diodes were investigated. Both materials characterization (X-ray diffraction analysis, Rutherford backscattering spectrometry (RBS), Auger depth profiling) and electrical measurements (reverse-biased junction leakage current-density) were used to evaluate diffusion barrier properties of the thin films. The leakage current density of p + n diodes with the barrier (Ta-O-N) was approximately four orders of magnitude lower than those without barriers after a 30 min, 400 deg. C back contact anneal. The Ta-O-N barriers were stable up to 500 deg. C, 30 min anneals. However, this was not the case for the 600 deg. C anneal. RBS spectra and cross-sectional transmission electron microscopy of as-deposited and vacuum annealed samples of Ag/barrier (Ta-O-N)/Si indicate the absence of any interfacial interaction between the barrier and substrate (silicon). The failure of the Ta-O-N barriers has been attributed to thermally induced stresses, which cause the thin film to crack at elevated temperatures

  3. Highly transparent and conductive thin films fabricated with nano-silver/double-walled carbon nanotube composites.

    Science.gov (United States)

    Lee, Shie-Heng; Teng, Chih-Chun; Ma, Chen-Chi M; Wang, Ikai

    2011-12-01

    This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Simple Methods for Production of Nanoscale Metal Oxide Films from Household Sources

    Science.gov (United States)

    Campbell, Dean J.; Baliss, Michelle S.; Hinman, Jordan J.; Ziegenhorn, John W.; Andrews, Mark J.; Stevenson, Keith J.

    2013-01-01

    Production of thin metal oxide films was recently explored as part of an outreach program with a goal of producing nanoscale structures with household items. Household items coated with various metals or titanium compounds can be heated to produce colorful films with nanoscale thicknesses. As part of a materials chemistry laboratory experiment…

  5. Influence of silver incorporation on the structural and electrical properties of diamond-like carbon thin films.

    Science.gov (United States)

    Dwivedi, Neeraj; Kumar, Sushil; Carey, J David; Tripathi, R K; Malik, Hitendra K; Dalai, M K

    2013-04-10

    A simple approach is proposed for obtaining low threshold field electron emission from large area diamond-like carbon (DLC) thin films by sandwiching either Ag dots or a thin Ag layer between DLC and nitrogen-containing DLC films. The introduction of silver and nitrogen is found to reduce the threshold field for emission to under 6 V/μm representing a near 46% reduction when compared with unmodified films. The reduction in the threshold field is correlated with the morphology, microstructure, interface, and bonding environment of the films. We find modifications to the structure of the DLC films through promotion of metal-induced sp2 bonding and the introduction of surface asperities, which significantly reduce the value of the threshold field. This can lead to the next-generation, large-area simple and inexpensive field emission devices.

  6. Structure and photoelectrochemistry of silver-copper-indium-diselenide ((AgCu)InSe2) thin film

    Science.gov (United States)

    Zhang, Lin Rui; Li, Tong; Wang, Hao; Pang, Wei; Chen, Yi Chuan; Song, Xue Mei; Zhang, Yong Zhe; Yan, Hui

    2018-02-01

    In this work, silver (Ag) precursors with different thicknesses were sputtered on the surfaces of CuIn alloys, and (AgCu)InSe2 (ACIS) films were formed after selenization at 550 °C under nitrogen condition using a rapid thermal process furnace. The structure and electrical properties of the ACIS films were investigated. The result showed that the distribution of Ag+ ion was more uniform with increasing the thickness of Ag precursor, and the surface of the thin-film became more homogeneous and denser. When Ag/Cu ratio ≥0.249, the small grain particles disappeared. The band gap can be rationally controlled by adjusting Ag content. When (Ag + Cu)/In ratio ≥ 1.15, the surface of the ACIS thin-film mainly exhibited n-type semiconductor. Through the photoelectrochemistry measurement, it was observed that the incorporation of Ag+ ions could improve photocurrent by adjusting the band gap. With the Ag precursor thickness increased, the dark current decreased at the more negative potential.

  7. Evaporation characteristics of thin film liquid argon in nano-scale confinement: A molecular dynamics study

    Science.gov (United States)

    Hasan, Mohammad Nasim; Shavik, Sheikh Mohammad; Rabbi, Kazi Fazle; Haque, Mominul

    2016-07-01

    Molecular dynamics simulation has been carried out to explore the evaporation characteristics of thin liquid argon film in nano-scale confinement. The present study has been conducted to realize the nano-scale physics of simultaneous evaporation and condensation inside a confined space for a three phase system with particular emphasis on the effect of surface wetting conditions. The simulation domain consisted of two parallel platinum plates; one at the top and another at the bottom. The fluid comprised of liquid argon film at the bottom plate and vapor argon in between liquid argon and upper plate of the domain. Considering hydrophilic and hydrophobic nature of top and bottom surfaces, two different cases have been investigated: (i) Case A: Both top and bottom surfaces are hydrophilic, (ii) Case B: both top and bottom surfaces are hydrophobic. For all cases, equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. Then the lower wall was set to four different temperatures such as 110 K, 120 K, 130 K and 140 K to perform non-equilibrium molecular dynamics (NEMD). The variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat fluxes normal to top and bottom walls were estimated and discussed to illuminate the effectiveness of heat transfer in both hydrophilic and hydrophobic confinement at various boundary temperatures of the bottom plate.

  8. Identification of nanoscale structure and morphology reconstruction in oxidized a-SiC:H thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vasin, A.V.; Rusavsky, A.V.; Nazarov, A.N.; Lysenko, V.S.; Lytvyn, P.M.; Strelchuk, V.V. [Lashkaryov Institute of Semiconductor Physics, 41 Nauki Pr., Kiev 03028 (Ukraine); Kholostov, K.I.; Bondarenko, V.P. [Belarusian State University of Informatics and Radioelectronics, 6P. Brovki Str., Minsk 220013 (Belarus); Starik, S.P. [Bakul Institute of Superhard Materials, 2 Avtzavodskaya Str., Kiev 04074 (Ukraine)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer Increase of magnetron discharge power results in densification of a-SiC:H thin films. Black-Right-Pointing-Pointer The denser a-SiC:H material the better resistance to oxidation by oxygen. Black-Right-Pointing-Pointer Oxidation of soft a-SiC:H films can result in increase of electric conductivity. Black-Right-Pointing-Pointer Formation of graphitic clusters was found in a-SiC:H after annealing in oxygen. - Abstract: Oxidation behavior of a-SiC:H layers deposited by radio-frequency magnetron sputtering technique was examined by Kelvin probe force microscopy (KPFM) in combination with scanning electron microscopy, Fourier-transform infra-red spectroscopy and submicron selected area Raman scattering spectroscopy. Partially oxidized a-SiC:H samples (oxidation at 600 Degree-Sign C in oxygen) were examined to clarify mechanism of the oxidation process. Nanoscale and microscale morphological defects (pits) with dimension of about 50 nm and several microns respectively have appeared after thermal treatment. KPFM measurements exhibited the surface potential of the material in micro pits is significantly smaller in comparison with surrounding material. Submicron RS measurements indicates formation of graphite-like nano-inclusions in the pit defects. We conclude that initial stage of oxidation process in a-SiC:H films takes place not homogeneously throughout the layer but it is initiated in local nanoscale regions followed by spreading over all layer.

  9. Buckling of Thin Films in Nano-Scale

    Directory of Open Access Journals (Sweden)

    Li L.A.

    2010-06-01

    Full Text Available Investigation of thin film buckling is important for life prediction of MEMS device which are damaged mainly by the delamination and buckling of thin films. In this paper the mechanical and thermal properties of compressed thin film titanium films with 150 nm thickness deposited on an organic glass substrate under mechanical and thermal loads were measured and characterized. In order to simulate the thin films which subjected to compound loads and the buckle modes the external uniaxial compression and thermal loading were subjected to the specimen by the symmetric loading device and the electrical film in this experiment. The temperature of the thin film deposited on substrate was measured using thermoelectric couple. The range of temperature accords with the temperature range of the MEMS. It is found that the size and number of the delamination and buckling of the film are depended upon the pre-fixed mechanical loading and thermal temperature. The thermal transient conduction and thermal stability of the film and substrate was studied with finite element method.

  10. Optical properties and plasmonic response of silver-gallium nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lereu, A. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 (United States); Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille (France); Lemarchand, F.; Zerrad, M. [Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille (France); Yazdanpanah, M. [NaugaNeedles LLC, Louisville, Kentucky 40299 (United States); Passian, A., E-mail: passianan@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 (United States); Department of Physics, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200 (United States)

    2015-02-14

    Silver and gallium form an alloy Ag{sub 2}Ga via a room temperature spontaneous self-assembly that exhibits remarkable mechanical and electrical properties suitable for nanoscale measurements. However, whether photon excitation of plasmons in this emerging nanomaterial is retained or not has not been established. Here, we present a thin film formation of Ag{sub 2}Ga via a spreading-reactive process of liquid Ga on an Ag film and a characterization of its dielectric function ϵ(E) = ϵ{sub 1}(E) + iϵ{sub 2}(E) in the photon energy range 1.42 eV ≤ E < 4.2 eV. It is observed that while the plasmon damping increases, near an energy of 2.25 eV, the real part of ϵ exhibits a crossing with respect to that of Ag. Furthermore, the impact of new plasmon supporting materials is discussed and in order to enable further applications in plasmonics, the possibility of photon excitation of surface plasmons in Ag{sub 2}Ga is studied.

  11. Using Spin-Coated Silver Nanoparticles/Zinc Oxide Thin Films to Improve the Efficiency of GaInP/(InGaAs/Ge Solar Cells

    Directory of Open Access Journals (Sweden)

    Po-Hsun Lei

    2018-06-01

    Full Text Available We synthesized a silver nanoparticle/zinc oxide (Ag NP/ZnO thin film by using spin-coating technology. The treatment solution for Ag NP/ZnO thin film deposition contained zinc acetate (Zn(CH3COO2, sodium hydroxide (NaOH, and silver nitrate (AgNO3 aqueous solutions. The crystalline characteristics, surface morphology, content of elements, and reflectivity of the Ag NPs/ZnO thin film at various concentrations of the AgNO3 aqueous solution were investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and ultraviolet–visible–near infrared spectrophotometry. The results indicated that the crystalline structure, Ag content, and reflectance of Ag NP/ZnO thin films depended on the AgNO3 concentration. Hybrid antireflection coatings (ARCs composed of SiNx and Ag NPs/ZnO thin films with various AgNO3 concentrations were deposited on GaInP/(InGaAs/Ge solar cells. We propose that the optimal ARC consists of SiNx and Ag NP/ZnO thin films prepared using a treatment solution of 0.0008 M AgNO3, 0.007 M Zn(CH3COO2, and 1 M NaOH, followed by post-annealing at 200 °C. GaInP/(AlGaAs/Ge solar cells with the optimal hybrid ARC and SiNx ARC exhibit a conversion efficiency of 34.1% and 30.2% with Voc = 2.39 and 2.4 V, Jsc = 16.63 and 15.37 mA/cm2, and fill factor = 86.1% and 78.8%.

  12. The fabrication of highly ordered silver nanodot patterns by platinum assisted nanoimprint lithography

    International Nuclear Information System (INIS)

    Yoo, Hae-Wook; Jung, Jin-Mi; Lee, Su-kyung; Jung, Hee-Tae

    2011-01-01

    Silver has been widely used for optical sensing and imaging applications which benefit from localized surface plasmon resonance (LSPR) in a nanoscale configuration. Many attempts have been made to fabricate and control silver nanostructures in order to improve the high performance in sensing and other applications. However, a fatal mechanical weakness of silver and a lack of durability in oxygen-rich conditions have disrupted the manufacturing of reproducible nanostructures by the top-down lithography approach. In this study, we suggest a steady fabrication strategy to obtain highly ordered silver nanopatterns that are able to provide tunable LSPR characteristics. By using a protecting layer of platinum on a silver surface in the lithography process, we successfully obtained large-area (2.7 x 2.7 mm 2 ) silver nanopatterns with high reproducibility. This large-area silver nanopattern was capable of enhancing the low concentration of a Cy3 fluorescence signal (∼10 -10 M) which was labeled with DNA oligomers.

  13. Predictive modeling of nanoscale domain morphology in solution-processed organic thin films

    Science.gov (United States)

    Schaaf, Cyrus; Jenkins, Michael; Morehouse, Robell; Stanfield, Dane; McDowall, Stephen; Johnson, Brad L.; Patrick, David L.

    2017-09-01

    The electronic and optoelectronic properties of molecular semiconductor thin films are directly linked to their extrinsic nanoscale structural characteristics such as domain size and spatial distributions. In films prepared by common solution-phase deposition techniques such as spin casting and solvent-based printing, morphology is governed by a complex interrelated set of thermodynamic and kinetic factors that classical models fail to adequately capture, leaving them unable to provide much insight, let alone predictive design guidance for tailoring films with specific nanostructural characteristics. Here we introduce a comprehensive treatment of solution-based film formation enabling quantitative prediction of domain formation rates, coverage, and spacing statistics based on a small number of experimentally measureable parameters. The model combines a mean-field rate equation treatment of monomer aggregation kinetics with classical nucleation theory and a supersaturation-dependent critical nucleus size to solve for the quasi-two-dimensional temporally and spatially varying monomer concentration, nucleation rate, and other properties. Excellent agreement is observed with measured nucleation densities and interdomain radial distribution functions in polycrystalline tetracene films. Numerical solutions lead to a set of general design rules enabling predictive morphological control in solution-processed molecular crystalline films.

  14. Highly efficient silver patterning without photo-resist using simple silver precursors

    International Nuclear Information System (INIS)

    Byun, Younghun; Hwang, Eoc-Chae; Lee, Sang-Yun; Lyu, Yi-Yeol; Yim, Jin-Heong; Kim, Jin-Young; Chang, Seok; Pu, Lyong Sun; Kim, Ji Man

    2005-01-01

    Highly efficient method for silver patterning without photo-resist was developed by using high photosensitive organo-silver precursors, which were prepared by a simple reaction of silver salts and excess of amines. The FT-IR and GC-MS spectra were recorded depending on UV exposure time, for (n-PrNH 2 )Ag(NO 3 ).0.5MeCN and (n-PrNH 2 )Ag(NO 2 ).0.5MeCN, to understand the photolysis mechanism. The results indicate not only dissociation of coordinated amine and acetonitrile, but also decomposition of corresponding anion upon UV irradiation. When a precursor thin film was exposed to broadband UV irradiation, a partially reduced and insoluble silver species were formed within several minutes. After development, the irradiated areas were treated with a reducing agent to obtain pure metallic patterns. Subsequently, annealing step was followed at 100-350 deg. C to increase the adhesion of interface and cohesion of silver particles. The line resolution of 5 μm was obtained by the present silver precursors. Film thickness was also controllable from 50 to 250 nm by repetition of the above procedure. The average electrical conductivity was in the range of 3-43 Ω cm, measured by four-point probe technique. AES depth profile of the silver pattern thus obtained showed carbon and oxygen contents are less than 1% through the whole range. Even though sulfur contaminant exists on the surface, it was believed that nearly pure silver pattern was generated

  15. Colloidal silver fabrication using the spark discharge system and its antimicrobial effect on Staphylococcus aureus.

    Science.gov (United States)

    Tien, Der-Chi; Tseng, Kuo-Hsiung; Liao, Chih-Yu; Tsung, Tsing-Tshih

    2008-10-01

    Nanoscale techniques for silver production may assist the resurgence of the medical use of silver, especially given that pathogens are showing increasing resistance to antibiotics. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effectiveness of CS as an antibacterial agent. To counter these problems a spark discharge system (SDS) was used to fabricate a suspension of colloidal silver in deionized water with no added chemical surfactants. SDS-CS contains both metallic silver nanoparticles (Ag(0)) and ionic silver forms (Ag(+)). The antimicrobial affect of SDS-CS on Staphylococcus aureus was studied. The results show that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to destroy S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration.

  16. Participation of the Third Order Optical Nonlinearities in Nanostructured Silver Doped Zinc Oxide Thin Solid Films

    Directory of Open Access Journals (Sweden)

    C. Torres-Torres

    2012-01-01

    Full Text Available We report the transmittance modulation of optical signals in a nanocomposite integrated by two different silver doped zinc oxide thin solid films. An ultrasonic spray pyrolysis approach was employed for the preparation of the samples. Measurements of the third-order nonlinear optical response at a nonresonant 532 nm wavelength of excitation were performed using a vectorial two-wave mixing. It seems that the separated contribution of the optical nonlinearity associated with each film noticeable differs in the resulting nonlinear effects with respect to the additive response exhibited by the bilayer system. An enhancement of the optical Kerr nonlinearity is predicted for prime number arrays of the studied nanoclusters in a two-wave interaction. We consider that the nanostructured morphology of the thin solid films originates a strong modification of the third-order optical phenomena exhibited by multilayer films based on zinc oxide.

  17. The effect of the silver nanoparticles on the dynamics of singlet-singlet energy transfer of luminophores in thin films of polyvinyl alcohol

    International Nuclear Information System (INIS)

    Bryukhanov, V.V.; Samusev, I.G.; Slezhkin, V.A.; Tsibul'nikova, A.V.

    2014-01-01

    The effect of ablated silver nanoparticles (ANP) on the dynamics of non-radiative inductance-resonance energy transfer and phosphorescence in the donor-acceptor pair of molecules of eosin and methylene blue (MB) luminophores embedded in thin films of polyvinyl alcohol have been investigated. Increased fluorescence intensity of donor (eosin) and acceptor (MB) molecules, as well as a growth of the dipole-dipole transfer efficiency have been obtained under the resonant excitation of the silver ANP surface plasmons in the absorption band of the donor energy. The luminescence quantum yields and the fluorescence lifetimes have been measured. The energy transfer constants, degree of polarization and fluorescence anisotropy have been determined. (authors)

  18. Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

    Directory of Open Access Journals (Sweden)

    Ixtepan-Turrent Liliana

    2011-08-01

    Full Text Available Abstract The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles.

  19. Stable and Controllable Synthesis of Silver Nanowires for Transparent Conducting Film

    Science.gov (United States)

    Liu, Bitao; Yan, Hengqing; Chen, Shanyong; Guan, Youwei; Wu, Guoguo; Jin, Rong; Li, Lu

    2017-03-01

    Silver nanowires without particles are synthesized by a solvothermal method at temperature 150 °C. Silver nanowires are prepared via a reducing agent of glycerol and a capping agent of polyvinylpyrrolidone ( M w ≈ 1,300,000). Both of them can improve the purity of the as-prepared silver nanowires. With controllable shapes and sizes, silver nanowires are grown continuously up to 10-20 μm in length with 40-50 nm in diameter. To improve the yield of silver nanowires, the different concentrations of AgNO3 synthesis silver nanowires are discussed. The characterizations of the synthesized silver nanowires are analyzed by UV-visible absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM), and silver nanowires are pumped on the cellulose membrane and heated stress on the PET. Then, the cellulose membrane is dissolved by the steam of acetone to prepare flexible transparent conducting thin film, which is detected 89.9 of transmittance and 58 Ω/□. Additionally, there is a close loop connected by the thin film, a blue LED, a pair of batteries, and a number of wires, to determinate directly the film if conductive or not.

  20. Structure and composition of magnetocaloric Ni-Mn-In-Co thin films on the nanoscale - a TEM study

    Energy Technology Data Exchange (ETDEWEB)

    Erkartal, Burak; Schuermann, Ulrich; Kienle, Lorenz [Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University, Kiel (Germany); Duppel, Viola [Nanochemistry Max Planck Institute for Solid State Research, Stuttgart (Germany); Niemann, Robert; Schultz, Ludwig; Faehler, Sebastian [IFW Dresden (Germany)

    2012-08-15

    A complementary set of electron microscopy techniques is applied for the determination of structural and chemical segregation phenomena within a 300 nm thick metamagnetic Ni-Mn-In-Co thin film. The structure is predominantly composed of distinct modulated martensites of the 5M-, 6M-, 7M-, and 8M-type. Additionally these modulated structures exhibit twinning and stacking disordering. The nature of the disordering and the structural misfit at the twin interface were analyzed via high resolution micrographs. Next to an adhesion layer of Cr interdiffusion on the nanoscale was observed producing a penternary chemically and structurally homogeneous precipitate. The structure can be assigned to a twinned non-modulated pseudocubic model. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Observation of feature ripening inversion effect at the percolation threshold for the growth of thin silver films

    Energy Technology Data Exchange (ETDEWEB)

    Nehm, Frederik, E-mail: frederik.nehm@iapp.de; Schubert, Sylvio; Müller-Meskamp, Lars; Leo, Karl

    2014-04-01

    The growth behavior of thin silver films on organic layers is investigated during deposition by means of simultaneous in-situ monitoring of sheet resistance and transmittance. Thermally evaporated films up to 11 nm show a distinct percolation behavior with strong resistance drop at the percolation thickness. Additionally, evaporations are divided into a sequence of one nanometer steps. In the deposition breaks, the films exhibit a ripening effect with an inversion at the percolation thickness, by changing from an increasing to decreasing sheet resistance over time. Scanning electron micrographs suggest same ripening mechanisms for islands below the percolation thickness as for holes above. - Highlights: • Fundamental understanding of metal thin film growth is presented. • Optical and electrical in-situ measurements used for optimizing transparent electrodes • Stepwise Ag deposition reveals extraordinary ripening effects. • Feature ripening inversion is discovered at the percolation threshold.

  2. Observation of feature ripening inversion effect at the percolation threshold for the growth of thin silver films

    International Nuclear Information System (INIS)

    Nehm, Frederik; Schubert, Sylvio; Müller-Meskamp, Lars; Leo, Karl

    2014-01-01

    The growth behavior of thin silver films on organic layers is investigated during deposition by means of simultaneous in-situ monitoring of sheet resistance and transmittance. Thermally evaporated films up to 11 nm show a distinct percolation behavior with strong resistance drop at the percolation thickness. Additionally, evaporations are divided into a sequence of one nanometer steps. In the deposition breaks, the films exhibit a ripening effect with an inversion at the percolation thickness, by changing from an increasing to decreasing sheet resistance over time. Scanning electron micrographs suggest same ripening mechanisms for islands below the percolation thickness as for holes above. - Highlights: • Fundamental understanding of metal thin film growth is presented. • Optical and electrical in-situ measurements used for optimizing transparent electrodes • Stepwise Ag deposition reveals extraordinary ripening effects. • Feature ripening inversion is discovered at the percolation threshold

  3. Direct Inkjet Printing of Silver Source/Drain Electrodes on an Amorphous InGaZnO Layer for Thin-Film Transistors.

    Science.gov (United States)

    Ning, Honglong; Chen, Jianqiu; Fang, Zhiqiang; Tao, Ruiqiang; Cai, Wei; Yao, Rihui; Hu, Shiben; Zhu, Zhennan; Zhou, Yicong; Yang, Caigui; Peng, Junbiao

    2017-01-10

    Printing technologies for thin-film transistors (TFTs) have recently attracted much interest owing to their eco-friendliness, direct patterning, low cost, and roll-to-roll manufacturing processes. Lower production costs could result if electrodes fabricated by vacuum processes could be replaced by inkjet printing. However, poor interfacial contacts and/or serious diffusion between the active layer and the silver electrodes are still problematic for achieving amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs with good electrical performance. In this paper, silver (Ag) source/drain electrodes were directly inkjet-printed on an amorphous a-IGZO layer to fabricate TFTs that exhibited a mobility of 0.29 cm²·V -1 ·s -1 and an on/off current ratio of over 10⁵. To the best of our knowledge, this is a major improvement for bottom-gate top-contact a-IGZO TFTs with directly printed silver electrodes on a substrate with no pretreatment. This study presents a promising alternative method of fabricating electrodes of a-IGZO TFTs with desirable device performance.

  4. Direct Inkjet Printing of Silver Source/Drain Electrodes on an Amorphous InGaZnO Layer for Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Honglong Ning

    2017-01-01

    Full Text Available Printing technologies for thin-film transistors (TFTs have recently attracted much interest owing to their eco-friendliness, direct patterning, low cost, and roll-to-roll manufacturing processes. Lower production costs could result if electrodes fabricated by vacuum processes could be replaced by inkjet printing. However, poor interfacial contacts and/or serious diffusion between the active layer and the silver electrodes are still problematic for achieving amorphous indium–gallium–zinc–oxide (a-IGZO TFTs with good electrical performance. In this paper, silver (Ag source/drain electrodes were directly inkjet-printed on an amorphous a-IGZO layer to fabricate TFTs that exhibited a mobility of 0.29 cm2·V−1·s−1 and an on/off current ratio of over 105. To the best of our knowledge, this is a major improvement for bottom-gate top-contact a-IGZO TFTs with directly printed silver electrodes on a substrate with no pretreatment. This study presents a promising alternative method of fabricating electrodes of a-IGZO TFTs with desirable device performance.

  5. Ammonia sensing properties of silver nanocomposite with polypyrrole

    Science.gov (United States)

    Karmakar, N. S.; Kothari, D. C.; Bhat, N. V.

    2013-02-01

    Silver-polypyrrole nanocomposite thin film was prepared by a novel method. UV-Vis spectroscopic studies confirmed the presence of silver nanoparticles and also polymerization of pyrrole surrounding the silver nanoparticles. All the important X-ray diffraction peaks corresponding to silver were present in the composites. The silver nanoparticles and its composites with polypyrrole were observed by SEM and TEM. Electrical conductivity measurements were carried out using two probe method and it was found that the conductivity of nanocomposites is 10-5 S/cm. It was found that functionalized silver nanoparticles can act as efficient gas sensor for ammonia. The present result of the increase in conductivity with ammonia exposure is in contrast with the previously reported results of the decrease in conductivity.

  6. Interaction of positron beams with thin silver foils and surfaces

    International Nuclear Information System (INIS)

    Rysholt Poulsen, M.

    1994-01-01

    Experimental investigations of positron interactions with solid silver and the necessary platform to analyse the data have been presented. The main objective was to study Ps formation at a Ag(100) surface. The different ingredients of the scenario, including thermalization and diffusion of positrons and emission of Ps, were analysed and quantified in whatever way appropriate. The scattering and possible thermalization were described. The parametrization of Monte-Carlo simulated implantation profiles for semi-infinite materials were presented and the applicability of such profiles to thin foils assessed. The latter was done in conjunction with an analysis of experimental data on thermalization and diffusion in 1900 Aa Ag(100) foils. The necessity for MC simulated rather than parametrized implantation profiles was argued. The velocity of thermally desorbed Ps from a Ag(100) surface at ∼800 K appeared to obey and one-dimensional Maxwell Boltzmann distribution multiplied by a velocity dependent factor. More experimental investigations are needed before firm conclusions can be made on the nature of the emission process. The velocity distribution, though, was found to be near-thermal and indicative of the sample temperature. It has been shown that positrons can be converted into Ps atoms in the transmission geometry of a thin 1900 Aa Ag(100) foil with a high efficiency. Furthermore, 61% of the emitted Ps will have a mean velocity of v z =1.2x10 5 m/sec and 39% will have a maximum kinetic energy of 1.5 eV (v z =5.1x10 5 m/sec) at a foil temperature of 800 K, all velocities that are suitable for producing a 'dense' Ps gas target. (EG) 12 refs

  7. Fast and low-temperature sintering of silver complex using oximes as a potential reducing agent for solution-processible, highly conductive electrodes

    International Nuclear Information System (INIS)

    Yoo, Ji Hoon; Park, Su Bin; Kim, Ji Man; Han, Dae Sang; Chae, Jangwoo; Kwak, Jeonghun

    2014-01-01

    Highly conductive, solution-processed silver thin-films were obtained at a low sintering temperature of 100 °C in a short sintering time of 10 min by introducing oximes as a potential reductant for silver complex. The thermal properties and reducibility of three kinds of oximes, acetone oxime, 2-butanone oxime, and one dimethylglyoxime, were investigated as a reducing agent, and we found that the thermal decomposition product of oximes (ketones) accelerated the conversion of silver complex into highly conductive silver at low sintering temperature in a short time. Using the acetone oxime, the silver thin-film exhibited the lowest surface resistance (0.91 Ω sq −1 ) compared to those sing other oximes. The silver thin-film also showed a high reflectance of 97.8%, which is comparable to evaporated silver films. We also demonstrated inkjet printed silver patterns with the oxime-added silver complex inks. (paper)

  8. Silver doped metal layers for medical applications

    International Nuclear Information System (INIS)

    Kocourek, T; Jelínek, M; Mikšovský, J; Jurek, K; Weiserová, M

    2014-01-01

    Biological, physical and mechanical properties of silver-doped layers of titanium alloy Ti6Al4V and 316L steel prepared by pulsed laser deposition were studied. Metallic silver-doped coatings could be a new route for antibacterial protection in medicine. Thin films of silver and silver-doped materials were synthesized using KrF excimer laser deposition. The materials were ablated from two targets, which were composed either from titanium alloy with silver segments or from steel with silver segments. The concentration of silver ranged from 1.54 at% to 4.32 at% for steel and from 3.04 at% to 13.05 at% for titanium alloy. The layer properties such as silver content, structure, adhesion, surface wettability, and antibacterial efficacy (evaluated by Escherichia coli and Bacillus subtilis bacteria) were measured. Film adhesion was studied using scratch test. The antibacterial efficacy changed with silver doping up to 99.9 %. Our investigation was focused on minimum Ag concentration needed to reach high antibacterial efficiency, high film adhesion, and hardness.

  9. Silver-doped metal layers for medical applications

    International Nuclear Information System (INIS)

    Kocourek, T; Jelínek, M; Mikšovský, J; Jurek, K; Weiserová, M

    2014-01-01

    Biological, physical and mechanical properties of silver-doped layers of titanium alloy Ti6Al4V and 316 L steel prepared by pulsed laser deposition were studied. Metallic silver-doped coatings could be a new route for antibacterial protection in medicine. Thin films of silver and silver-doped materials were synthesized using KrF excimer laser deposition. The materials were ablated from two targets, which were composed either from titanium alloy with silver segments or from steel with silver segments. The concentration of silver ranged from 1.54 to 4.32 at% for steel and from 3.04 to 13.05 at% for titanium alloy. The layer properties such as silver content, structure, adhesion, surface wettability, and antibacterial efficiency (evaluated by Escherichia coli and Bacillus subtilis bacteria) were measured. Film adhesion was studied using a scratch test. The antibacterial efficiency changed with silver doping up to 99.9 %. Our investigation was focused on the minimum Ag concentration needed to reach high antibacterial efficiency, high film adhesion, and hardness. (paper)

  10. Nanoscale patterning of two metals on silicon surfaces using an ABC triblock copolymer template.

    Science.gov (United States)

    Aizawa, Masato; Buriak, Jillian M

    2006-05-03

    Patterning technologically important semiconductor interfaces with nanoscale metal films is important for applications such as metallic interconnects and sensing applications. Self-assembling block copolymer templates are utilized to pattern an aqueous metal reduction reaction, galvanic displacement, on silicon surfaces. Utilization of a triblock copolymer monolayer film, polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO), with two blocks capable of selective transport of different metal complexes to the surface (PEO and P2VP), allows for chemical discrimination and nanoscale patterning. Different regions of the self-assembled structure discriminate between metal complexes at the silicon surface, at which time they undergo the spontaneous reaction at the interface. Gold deposition from gold(III) compounds such as HAuCl4(aq) in the presence of hydrofluoric acid mirrors the parent block copolymer core structure, whereas silver deposition from Ag(I) salts such as AgNO3(aq) does the opposite, localizing exclusively under the corona. By carrying out gold deposition first and silver second, sub-100-nm gold features surrounded by silver films can be produced. The chemical selectivity was extended to other metals, including copper, palladium, and platinum. The interfaces were characterized by a variety of methods, including scanning electron microscopy, scanning Auger microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy.

  11. Enhanced photocatalytic activity of silver-doped nanoparticulate TiO.sub.2./sub. thin films with respect to the method of doping

    Czech Academy of Sciences Publication Activity Database

    Kment, Štěpán; Kmentová, Hana; Hubička, Zdeněk; Olejníček, Jiří; Čada, Martin; Krýsa, J.

    2015-01-01

    Roč. 41, č. 12 (2015), s. 9343-9355 ISSN 0922-6168 R&D Projects: GA ČR GAP108/12/2104; GA MŠk LH12043 Grant - others:AVČR(CZ) M100101215 Institutional support: RVO:68378271 ; RVO:67985858 Keywords : thin layers * TiO 2 * silver doping * photocatalysis * photoelectrochemistry Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.833, year: 2015

  12. Facile approach to the fabrication of a micropattern possessing nanoscale substructure.

    Science.gov (United States)

    Ji, Qiang; Jiang, Xuesong; Yin, Jie

    2007-12-04

    On the basis of the combined technologies of photolithography and reaction-induced phase separation (RIPS), a facile approach has been successfully developed for the fabrication of a micropattern possessing nanoscale substructure on the thin film surface. This approach involves three steps. In the first step, a thin film was prepared by spin coating from a solution of a commercial random copolymer, polystyrene-r-poly(methyl methacrylate) (PS-r-PMMA) and a commercial crosslinker, trimethylolpropane triacrylate (TMPTA). In the second step, photolithograph was performed with the thin film using a 250 W high-pressure mercury lamp to produce the micropattern. Finally, the resulting micropattern was annealed at 200 degrees C for a certain time, and reaction-induced phase separation occurred. After soaking in chloroform for 4 h, nanoscale substructure was obtained. The whole processes were traced by atomic force microscopy (AFM), X-ray photoelectron spectrometry (XPS), and Fourier transform infrared (FTIR) spectroscopy, and the results supported the proposed structure.

  13. Scanning nanoscale multiprobes for conductivity measurements

    DEFF Research Database (Denmark)

    Bøggild, Peter; Hansen, Torben Mikael; Kuhn, Oliver

    2000-01-01

    We report fabrication and measurements with two- and four-point probes with nanoscale dimensions, for high spatial resolution conductivity measurements on surfaces and thin films. By combination of conventional microfabrication and additive three-dimensional nanolithography, we have obtained...... electrode spacings down to 200 nm. At the tips of four silicon oxide microcantilevers, narrow carbon tips are grown in converging directions and subsequently coated with a conducting layer. The probe is placed in contact with a conducting surface, whereby the electrode resistance can be determined....... The nanoelectrodes withstand considerable contact force before breaking. The probe offers a unique possibility to position the voltage sensors, as well as the source and drain electrodes in areas of nanoscale dimensions. ©2000 American Institute of Physics....

  14. Role of aluminum in silver paste contact to boron-doped silicon emitters

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2017-01-01

    Full Text Available The addition of aluminum to silver metallization pastes has been found to lower the contact resistivity of a silver metallization on boron-doped silicon emitters for n-type Si solar cells. However, the addition of Al also induces more surface recombination and increases the Ag pattern′s line resistivity, both of which ultimately limit the cell efficiency. There is a need to develop a fundamental understanding of the role that Al plays in reducing the contact resistivity and to explore alternative additives. A fritless silver paste is used to allow direct analysis of the impact of Al on the Ag-Si interfacial microstructure and isolate the influence of Al on the electrical contact from the complicated Ag-Si interfacial glass layer. Electrical analysis shows that in a simplified system, Al decreases the contact resistivity by about three orders of magnitude. Detailed microstructural studies show that in the presence of Al, microscale metallic spikes of Al-Ag alloy and nanoscale metallic spikes of Ag-Si alloy penetrate the surface of the boron-doped Si emitters. These results demonstrate the role of Al in reducing the contact resistivity through the formation of micro- and nano-scale metallic spikes, allowing the direct contact to the emitters.

  15. Femtosecond laser direct writing of monocrystalline hexagonal silver prisms

    Energy Technology Data Exchange (ETDEWEB)

    Vora, Kevin; Kang, SeungYeon; Moebius, Michael [School of Engineering and Applied Sciences, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138 (United States); Mazur, Eric [School of Engineering and Applied Sciences, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138 (United States); Department of Physics, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138 (United States)

    2014-10-06

    Bottom-up growth methods and top-down patterning techniques are both used to fabricate metal nanostructures, each with a distinct advantage: One creates crystalline structures and the other offers precise positioning. Here, we present a technique that localizes the growth of metal crystals to the focal volume of a laser beam, combining advantages from both approaches. We report the fabrication of silver nanoprisms—hexagonal nanoscale silver crystals—through irradiation with focused femtosecond laser pulses. The growth of these nanoprisms is due to a nonlinear optical interaction between femtosecond laser pulses and a polyvinylpyrrolidone film doped with silver nitrate. The hexagonal nanoprisms have bases hundreds of nanometers in size and the crystal growth occurs over exposure times of less than 1 ms (8 orders of magnitude faster than traditional chemical techniques). Electron backscatter diffraction analysis shows that the hexagonal nanoprisms are monocrystalline. The fabrication method combines advantages from both wet chemistry and femtosecond laser direct-writing to grow silver crystals in targeted locations. The results presented in this letter offer an approach to directly positioning and growing silver crystals on a substrate, which can be used for plasmonic devices.

  16. Femtosecond laser direct writing of monocrystalline hexagonal silver prisms

    International Nuclear Information System (INIS)

    Vora, Kevin; Kang, SeungYeon; Moebius, Michael; Mazur, Eric

    2014-01-01

    Bottom-up growth methods and top-down patterning techniques are both used to fabricate metal nanostructures, each with a distinct advantage: One creates crystalline structures and the other offers precise positioning. Here, we present a technique that localizes the growth of metal crystals to the focal volume of a laser beam, combining advantages from both approaches. We report the fabrication of silver nanoprisms—hexagonal nanoscale silver crystals—through irradiation with focused femtosecond laser pulses. The growth of these nanoprisms is due to a nonlinear optical interaction between femtosecond laser pulses and a polyvinylpyrrolidone film doped with silver nitrate. The hexagonal nanoprisms have bases hundreds of nanometers in size and the crystal growth occurs over exposure times of less than 1 ms (8 orders of magnitude faster than traditional chemical techniques). Electron backscatter diffraction analysis shows that the hexagonal nanoprisms are monocrystalline. The fabrication method combines advantages from both wet chemistry and femtosecond laser direct-writing to grow silver crystals in targeted locations. The results presented in this letter offer an approach to directly positioning and growing silver crystals on a substrate, which can be used for plasmonic devices.

  17. Examining Wetting and Dewetting Processes in Thin-films on Crystalline Substrates at the Nanoscale

    Science.gov (United States)

    Hihath, Sahar

    Controlling the wetting and dewetting of ultra-thin films on solid substrates is important for a variety of technological and fundamental research applications. These applications include film deposition for semiconductor manufacturing, the growth of nanowires through nanoparticle-based catalysis sites, to making ordered arrays of nanoscale particles for electronic and optical devices. However, despite the importance of these processes, the underlying mechanisms by which a film wets a surface or dewets from it is still often unclear and widely debated. In this dissertation we examine wetting and dewetting processes in three materials systems that are relevant for device applications with the ultimate goal of understanding what mechanisms drive the wetting (or dewetting) process in each case. First, we examine the formation of wetting layers between nanoparticle films and highly conductive GaAs substrates for spintronic applications. In this case, the formation of a wetting layer is important for nanoparticle adhesion on the substrate surface. Wetting layers can be made by annealing these systems, which causes elemental diffusion from nanoparticles into the substrate, thereby adhesion between the nanoparticles and the substrate. Here we investigate the feasibility of forming a wetting layer underneath nanoparticles post-annealing in a system of Fe3O4 nanoparticles on a (100) GaAs substrate by studying the interface structure and composition via Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDXS). Electron Energy-Loss fine structures of the Fe-L 3,2 and O-K absorption edges were quantitatively analyzed to gain insight about the compositional gradient of the interface between the nanoparticles and the GaAs substrate. Additionally, real-space density functional theory calculations of the dynamical form factor was performed to confirm the

  18. A Water-Based Silver-Nanowire Screen-Print Ink for the Fabrication of Stretchable Conductors and Wearable Thin-Film Transistors.

    Science.gov (United States)

    Liang, Jiajie; Tong, Kwing; Pei, Qibing

    2016-07-01

    A water-based silver-nanowire (AgNW) ink is formulated for screen printing. Screen-printed AgNW patterns have uniform sharp edges, ≈50 μm resolution, and electrical conductivity as high as 4.67 × 10(4) S cm(-1) . The screen-printed AgNW patterns are used to fabricate a stretchable composite conductor, and a fully printed and intrinsically stretchable thin-film transistor array is also realized. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Nano-structural characteristics and optical properties of silver chiral nano-flower sculptured thin films

    International Nuclear Information System (INIS)

    Savaloni, Hadi; Haydari-Nasab, Fatemh; Malmir, Mariam

    2011-01-01

    Silver chiral nano-flowers with 3-, 4- and 5-fold symmetry were produced using oblique angle deposition method in conjunction with the rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM), were employed to obtain morphology and nano-structure of the films. Optical characteristics of silver chiral nano-flower thin films were obtained using single beam spectrophotometer with both s- and p-polarization incident light at 30 o and 70 o incidence angles and at different azimuthal angles (φ). Optical spectra showed both TM (TDM (transverse dipole mode) and TQM (transverse quadruple mode)) and LM (longitudinal mode) Plasmon resonance peaks. For 3- and 4-fold symmetry chiral nano-flowers the s-polarization extinction spectra obtained at different azimuthal angles did not show significant change in the Plasmon peak position while 5-fold symmetry chiral nano-flower showed a completely different behavior, which may be the result of increased surface anisotropy, so when the φ angle is changed the s-polarization response from the surface can change more significantly than that for lower symmetries. In general, for 3-, 4- and 5-fold symmetry chiral nano-flowers a sharp peak at lower wavelengths ( o incidence angle.

  20. Complex conductivity response to silver nanoparticles in ...

    Science.gov (United States)

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0–30%), nanoparticle concentrations (0–10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90–210 and 1500–2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex co

  1. Method for preparing microstructure arrays on the surface of thin film material

    KAUST Repository

    Wang, Peng; Tang, Bo; Zhang, Lianbin

    2017-01-01

    Methods are provided for growing a thin film of a nanoscale material. Thin films of nanoscale materials are also provided. The films can be grown with microscale patterning. The method can include vacuum filtration of a solution containing the nanostructured material through a porous substrate. The porous substrate can have a pore size that is comparable to the size of the nanoscale material. By patterning the pores on the surface of the substrate, a film can be grown having the pattern on a surface of the thin film, including on the top surface opposite the substrate. The nanoscale material can be graphene, graphene oxide, reduced graphene oxide, molybdenum disulfide, hexagonal boron nitride, tungsten diselenide, molybdenum trioxide, or clays such as montmorillonite or lapnotie. The porous substrate can be a porous organic or inorganic membrane, a silicon stencil membrane, or similar membrane having pore sizes on the order of microns.

  2. Method for preparing microstructure arrays on the surface of thin film material

    KAUST Repository

    Wang, Peng

    2017-02-09

    Methods are provided for growing a thin film of a nanoscale material. Thin films of nanoscale materials are also provided. The films can be grown with microscale patterning. The method can include vacuum filtration of a solution containing the nanostructured material through a porous substrate. The porous substrate can have a pore size that is comparable to the size of the nanoscale material. By patterning the pores on the surface of the substrate, a film can be grown having the pattern on a surface of the thin film, including on the top surface opposite the substrate. The nanoscale material can be graphene, graphene oxide, reduced graphene oxide, molybdenum disulfide, hexagonal boron nitride, tungsten diselenide, molybdenum trioxide, or clays such as montmorillonite or lapnotie. The porous substrate can be a porous organic or inorganic membrane, a silicon stencil membrane, or similar membrane having pore sizes on the order of microns.

  3. Nanoscale wedge polishing of superconducting thin films-an easy way to obtain depth dependent information by surface analysis techniques

    International Nuclear Information System (INIS)

    Shapoval, T; Engel, S; Gruendlich, M; Meier, D; Backen, E; Neu, V; Holzapfel, B; Schultz, L

    2008-01-01

    A mechanical wedge polishing procedure that offers a simple, cost-effective and rapid way to look into the depth of a thin film with different surface-sensitive scanning techniques has been developed. As an example of its wide applicability, this method was utilized for the investigation of two differently prepared superconducting YBa 2 Cu 3 O 7-δ thin films: an Hf-doped film prepared by chemical solution deposition and an undoped film grown by pulsed laser deposition. Upon polishing, the roughness of the samples was reduced to less than 5 nm (peak-to-valley) without influencing the superconducting properties of the films. Thus, nanoscale polishing opens up a unique possibility for microscopic studies with various surface-sensitive techniques. We demonstrate the successful imaging of flux lines by low temperature magnetic force microscopy after polishing a formerly rough as-prepared film. By applying the wedge polishing procedure to the Hf-doped sample, high resolution electron backscattering diffraction investigations reveal the homogeneous distribution of non-superconducting BaHfO 3 nanoparticles in the whole volume of the film

  4. Non-linear optics of nano-scale pentacene thin film

    Science.gov (United States)

    Yahia, I. S.; Alfaify, S.; Jilani, Asim; Abdel-wahab, M. Sh.; Al-Ghamdi, Attieh A.; Abutalib, M. M.; Al-Bassam, A.; El-Naggar, A. M.

    2016-07-01

    We have found the new ways to investigate the linear/non-linear optical properties of nanostructure pentacene thin film deposited by thermal evaporation technique. Pentacene is the key material in organic semiconductor technology. The existence of nano-structured thin film was confirmed by atomic force microscopy and X-ray diffraction. The wavelength-dependent transmittance and reflectance were calculated to observe the optical behavior of the pentacene thin film. It has been observed the anomalous dispersion at wavelength λ 800. The non-linear refractive index of the deposited films was investigated. The linear optical susceptibility of pentacene thin film was calculated, and we observed the non-linear optical susceptibility of pentacene thin film at about 6 × 10-13 esu. The advantage of this work is to use of spectroscopic method to calculate the liner and non-liner optical response of pentacene thin films rather than expensive Z-scan. The calculated optical behavior of the pentacene thin films could be used in the organic thin films base advanced optoelectronic devices such as telecommunications devices.

  5. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    International Nuclear Information System (INIS)

    Han, I-H; Lee, I-S; Song, J-H; Lee, M-H; Park, J-C; Lee, G-H; Sun, X-D; Chung, S-M

    2007-01-01

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO 3 concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls

  6. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    Energy Technology Data Exchange (ETDEWEB)

    Han, I-H [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Lee, I-S [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Song, J-H [Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, M-H [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Park, J-C [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Lee, G-H [Korea Institute of Machinery and Materials, Chang-Won 641-010 (Korea, Republic of); Sun, X-D [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Chung, S-M [Implantium Research Center, Seoul 135-879 (Korea, Republic of)

    2007-09-15

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO{sub 3} concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls.

  7. Antibacterial performance on plasma polymerized heptylamine films loaded with silver nanoparticles

    Science.gov (United States)

    Lin, Yu-Chun; Lin, Chia-Chun; Lin, Chih-Hao; Wang, Meng-Jiy

    2017-01-01

    The antibacterial performance of the plasma-polymerized (pp) heptylamine thin films loaded with silver nanoparticles was evaluated against the colonization of Escherichia coli and Staphylococcus aureus. The properties including the thickness and chemical composition of the as deposited HApp films were modulated by adjusting plasma parameters. The acquired results showed that the film thickness was controlled in the range of 20 to 400 nm by adjusting deposition time. The subsequent immersion of the HApp thin films in silver nitrate solutions result in the formation of amine-metal complexes, in which the silver nanoparticles were reduced directly on the matrices to form Ag@HApp. The reduction reaction of silver was facilitated by applying NaBH4 as a reducing agent. The results of physicochemical analyses including morphological analysis and ellipsometry revealed that the silver nanoparticles were successfully reduced on the HApp films, and the amount of reduced silver was closely associated which the thickness of the plasma-polymerized films, the concentration of applied metal ions solutions, and the time of immobilization. Regarding the antibacterial performance, the Ag@HApp films reduced by NaBH4 showed antibacterial abilities of 70.1 and 68.2% against E. coli and S. aureus, respectively.

  8. Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Fang-Wei [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); Ke, Wen-Cheng, E-mail: wcke@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Cheng, Chun-Hong; Liao, Bo-Wei; Chen, Wei-Kuo [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China)

    2016-07-01

    Highlights: • Nanoscale patterned sapphire substrate was prepared by anodic-aluminum-oxide etching mask. • Influence of aspect ratio of NPSS on structural and electrical properties of GaN films was studied. • Low dislocation density and high carrier mobility of GaN films were grown on high aspect ratio NPSS. - Abstract: This study presents GaN thin films grown on nanoscale-patterned sapphire substrates (NPSSs) with different aspect ratios (ARs) using a homemade metal-organic chemical vapor deposition system. The anodic aluminum oxide (AAO) technique is used to prepare the dry etching mask. The cross-sectional view of the scanning electron microscope image shows that voids exist between the interface of the GaN thin film and the high-AR (i.e. ∼2) NPSS. In contrast, patterns on the low-AR (∼0.7) NPSS are filled full of GaN. The formation of voids on the high-AR NPSS is believed to be due to the enhancement of the lateral growth in the initial growth stage, and the quick-merging GaN thin film blocks the precursors from continuing to supply the bottom of the pattern. The atomic force microscopy images of GaN on bare sapphire show a layer-by-layer surface morphology, which becomes a step-flow surface morphology for GaN on a high-AR NPSS. The edge-type threading dislocation density can be reduced from 7.1 × 10{sup 8} cm{sup −2} for GaN on bare sapphire to 4.9 × 10{sup 8} cm{sup −2} for GaN on a high-AR NPSS. In addition, the carrier mobility increases from 85 cm{sup 2}/Vs for GaN on bare sapphire to 199 cm{sup 2}/Vs for GaN on a high-AR NPSS. However, the increased screw-type threading dislocation density for GaN on a low-AR NPSS is due to the competition of lateral growth on the flat-top patterns and vertical growth on the bottom of the patterns that causes the material quality of the GaN thin film to degenerate. Thus, the experimental results indicate that the AR of the particular patterning of a NPSS plays a crucial role in achieving GaN thin film with

  9. Novel silver-based nanoclay as an antimicrobial in polylactic acid food packaging coatings.

    Science.gov (United States)

    Busolo, Maria A; Fernandez, Patricia; Ocio, Maria J; Lagaron, Jose M

    2010-11-01

    This paper presents a comprehensive performance study of polylactic acid (PLA) biocomposites, obtained by solvent casting, containing a novel silver-based antimicrobial layered silicate additive for use in active food packaging applications. The silver-based nanoclay showed strong antimicrobial activity against Gram-negative Salmonella spp. Despite the fact that no exfoliation of the silver-based nanoclay in PLA was observed, as suggested by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) experiments, the additive dispersed nicely throughout the PLA matrix to a nanoscale, yielding nanobiocomposites. The films were highly transparent with enhanced water barrier and strong biocidal properties. Silver migration from the films to a slightly acidified water medium, considered an aggressive food simulant, was measured by stripping voltammetry. Silver migration accelerated after 6 days of exposure. Nevertheless, the study suggests that migration levels of silver, within the specific migration levels referenced by the European Food Safety Agency (EFSA), exhibit antimicrobial activity, supporting the potential application of this biocidal additive in active food-packaging applications to improve food quality and safety.

  10. Nanoscale and submicron fatigue crack growth in nickel microbeams

    International Nuclear Information System (INIS)

    Yang, Y.; Yao, N.; Imasogie, B.; Soboyejo, W.O.

    2007-01-01

    This paper presents a novel edge-notched microbeam technique for the study of short fatigue crack growth. The technique is used to study submicron and nanoscale fatigue in LIGA Ni thin films with columnar microstructures. The edge-notched microbeams were fabricated within LIGA Ni thin films, using focused ion beam (FIB) techniques. The microbeams were then cyclically deformed to failure at a stress ratio of 0.1. Different slip-band structures were observed below the nanoscale notches. Cyclic deformation resulted in the formation of primary slip bands below the notch. Subsequent crack growth then occurred by the unzipping of fatigue cracks along intersecting slip bands. The effects of the primary slip bands were idealized using dislocation-based models. These were used to estimate the intrinsic fatigue threshold and the fatigue endurance limit. The estimates from the model are shown to be consistent with experimental data from prior stress-life experiments and current/prior fatigue threshold estimates

  11. Aggregation in thin-film silver: Induced by chlorine and inhibited by alloying with two dopants

    International Nuclear Information System (INIS)

    Koike, Katsuhiko; Shimada, Koichi; Fukuda, Shin

    2009-01-01

    The Ag aggregation mechanism triggered by chlorine (Cl) is discussed. The frontier orbital theory by K. Fukui is applied in order to determine the growing point in the silver (Ag) cluster. Ag in the thin-film silver would grow to Ag n Cl and stack, triggered by Cl from the outside according to the mechanism described. This would lead to an aggregate with a high Ag density. It is suggested that this would be the generating mechanism of the silver-gray aggregate consisting mostly of Ag, which is generated by exposing it to Cl. Two tactics in order to prevent restrain aggregation induced by Cl according to the mechanism are proposed. Tactic 1 is a restraining of structure change to a plane in the process of Ag 6 Cl + Ag → Ag 7 Cl. Tactic 2 is the trapping of Cl before it generates a bond to Ag. The ability of the two combined dopants with the abilities of tactics 1 and 2, such as in an Ag alloy including palladium and copper (APC), and including neodymium and gold (ANA) is expected to be very high. The aggregation resistance of an Ag alloy including two dopants is evaluated by a salt water immersion test. The APC and ANA demonstrated a very high resistance to Cl, because of the combination of the dopants working with tactic 1 (Pd, Au) and tactic 2 (Cu, Nd). The multilayer sputter coating with an ANA layer demonstrated a very interesting profile where the light transmittance and the electrical sheet resistance are almost the same as the multilayer sputter coating with a pure Ag. The multilayer sputter coating with AIS also demonstrates a very interesting profile, where the light transmittance is higher than the multilayer sputter coating with a pure Ag.

  12. Compact chromium oxide thin film resistors for use in nanoscale quantum circuits

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A. [London Centre for Nanotechnology, UCL, 17–19 Gordon Street, London WC1H 0AH (United Kingdom)

    2014-12-14

    We report on the electrical characterisation of a series of thin amorphous chromium oxide (CrO{sub x}) films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the CrO{sub x} films was varied from 28 Ω/◻ to 32.6 kΩ/◻. The variation in resistance with cooling to 4.2 K in liquid helium was investigated; the sheet resistance at 4.2 K varied with composition from 65 Ω/◻ to above 20 GΩ/◻. All of the films measured displayed linear current–voltage characteristics at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium–silicon nanowires, interfaces between niobium–silicon and chromium oxide are required. We also characterised the contact resistance for one CrO{sub x} composition at an interface with niobium–silicon. We found that a gold intermediate layer is favourable: the specific contact resistivity of chromium-oxide-to-gold interfaces was 0.14 mΩcm{sup 2}, much lower than the value for direct CrO{sub x} to niobium–silicon contact. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.

  13. The first report on SILAR deposited nano-structured uranyl sulphide thin films and their chemical conversion to silver sulphide

    International Nuclear Information System (INIS)

    Garole, Dipak J.; Tetgure, Sandesh R.; Borse, Amulrao U.; Yogesh R Toda; Vaman J Garole; Babasaheb R Sankapal; Prashant K Baviskar

    2015-01-01

    This paper reports the novel synthesis of uranyl sulphide (UO_2S) thin films using the successive ionic layer adsorption and reaction (SILAR) technique at room temperature. Cationic exchange reaction was used to convert uranyl sulphide (UO_2S) to silver sulphide (Ag_2S). The influence of concentration variation on the structural and optical properties of UO_2S and Ag_2S thin films was investigated. The structural, surface morphological, elemental analysis and optical absorption studies were performed. Structural studies revealed that all the deposited films were nano-sized and amorphous in nature. Surface morphology showed that all the grains were spherical and granular in nature and grains got conglomerated to form a large particle. Also, the variations of the optical band gap and the width of the tail of localized states were represented as a function of various parameters. (authors)

  14. Silver Clusters in Zeolites: From Self-Assembly to Ground-Breaking Luminescent Properties.

    Science.gov (United States)

    Coutiño-Gonzalez, Eduardo; Baekelant, Wouter; Steele, Julian A; Kim, Cheol Woong; Roeffaers, Maarten B J; Hofkens, Johan

    2017-09-19

    Interest for functional silver clusters (Ag-CLs) has rapidly grown over years due to large advances in the field of nanoscale fabrication and materials science. The continuous development of strategies to fabricate small-scale silver clusters, together with their interesting physicochemical properties (molecule-like discrete energy levels, for example), make them very attractive for a wide variety of applied research fields, from biotechnology and the environmental sciences to fundamental chemistry and physics. Apart from useful catalytic properties, silver clusters (Ag n , n counterbalancing ions, silver loading, and zeolite topology, and cannot be overlooked. This Account is intended to shed light on the current state-of-the-art of luminescent Ag-CLs confined in zeolitic matrices, emphasizing the use of combinatorial approaches to overcome problems associated with the correct characterization and correlation of their structural, electronic, and photoluminescence properties, all to establish the important design principles for developing functional silver-zeolite-based materials. Additionally, examples of emerging applications and future perspectives for functional luminescent Ag-zeolite materials are addressed in this Account.

  15. Patterning Method for Silver Nanoparticle Electrodes in Fully Solution-Processed Organic Thin-Film Transistors Using Selectively Treated Hydrophilic and Hydrophobic Surfaces

    Science.gov (United States)

    Fukuda, Kenjiro; Takeda, Yasunori; Kobayashi, Yu; Shimizu, Masahiro; Sekine, Tomohito; Kumaki, Daisuke; Kurihara, Masato; Sakamoto, Masatomi; Tokito, Shizuo

    2013-05-01

    Fully solution-processed organic thin-film transistor (OTFT) devices have been fabricated with simple patterning process at a relatively low process temperature of 100 °C. In the patterning process, a hydrophobic amorphous fluoropolymer material, which was used as the gate dielectric layer and the underlying base layer, was treated with an oxygen plasma to selectively change its surface wetting properties from hydrophobic to hydrophilic. Silver source and drain electrodes were successfully formed in the treated areas with highly uniform line widths and without residues between the electrodes. Nonuniformities in the thickness of the silver electrodes originating from the “coffee-ring” effect were suppressed by optimizing the blend of solvents used with the silver nanoparticles, such that the printed electrodes are appropriate for bottom-gate OTFT devices. A fully solution-processed OTFT device using a polymer semiconductor material (PB16TTT) exhibited good electrical performance with no hysteresis in its transfer characteristics and with good linearity in its output characteristics. A relatively high carrier mobility of 0.14 cm2 V-1 s-1 and an on/off ratio of 1×105 were obtained with the fabricated TFT device.

  16. Development of Nanoscale Graphitic Devices and The Transport Characterization

    International Nuclear Information System (INIS)

    Gunasekaran, Venugopal

    2011-02-01

    This dissertation describes the development of graphitic based nanoscale devices with its fabrication and transport characterization results. It covers graphite nano-scale stacked-junctions fabricated using focused ion beam (FIB) 3-D etching technique, a single layer graphite layer (graphene) preparation and its electrical transport characterization results and the synthesis and investigation of electrical transport behavior of graphene oxide based thin film devices. The first chapter describes the basic information about the carbon family in detail in which the electronic properties and structure of graphite, graphene and graphene oxide are discussed. In addition, the necessity of developing nanoscale graphitic devices is given. The second chapter explains the experimental techniques used in this research for fabricating nanoscale devices which includes focused ion beam 3-D fabrication procedures, mechanical exfoliation technique and photolithographic methods. In third chapter, we have reported the results on temperature dependence of graphite planar-type structures fabricated along ab-plane. In the fourth and fifth chapters, the fabrication and electrical transport characteristics of large in-plane area graphite planar-type structures (fabricated along ab-plane and c-axis) were discussed and their transport anisotropy properties were investigated briefly. In the sixth chapter, we focused the fabrication of the submicron sized graphite stacked junctions and their electrical transport characterization studies. In which, FIB was used to fabricated the submicron junctions with various in-plane area (with same stack height) are and their transport characteristics were compared. The seventh chapter reports investigation of electrical transport results of nanoscale graphite stacked-junctions in which the temperature dependent transport (R-T) studies, current-voltage measurements for the various in-plane areas and for various stack height samples were analyzed. The

  17. Formation of nanoparticles from thin silver films irradiated by laser pulses in air

    Science.gov (United States)

    Nastulyavichus, A. A.; Smirnov, N. A.; Kudryashov, S. I.; Ionin, A. A.; Saraeva, I. N.; Busleev, N. I.; Rudenko, A. A.; Khmel'nitskii, R. A.; Zayarnyi, D. A.

    2018-03-01

    Some specific features of the transport of silver nanoparticles onto a SiO2 substrate under focused nanosecond IR laser pulses is experimentally investigated. A possibility of obtaining silver coatings is demonstrated. The formation of silver nanostructures as a result of pulsed laser ablation in air is studied. Nanoparticles are formed by exposing a silver film to radiation of an HTF MARK (Bulat) laser marker (λ = 1064 nm). The thus prepared nanoparticles are analysed using scanning electron microscopy and optical spectroscopy.

  18. Nanoscale capacitance imaging with attofarad resolution using ac current sensing atomic force microscopy

    International Nuclear Information System (INIS)

    Fumagalli, L; Ferrari, G; Sampietro, M; Casuso, I; MartInez, E; Samitier, J; Gomila, G

    2006-01-01

    Nanoscale capacitance imaging with attofarad resolution (∼1 aF) of a nano-structured oxide thin film, using ac current sensing atomic force microscopy, is reported. Capacitance images are shown to follow the topographic profile of the oxide closely, with nanometre vertical resolution. A comparison between experimental data and theoretical models shows that the capacitance variations observed in the measurements can be mainly associated with the capacitance probed by the tip apex and not with positional changes of stray capacitance contributions. Capacitance versus distance measurements further support this conclusion. The application of this technique to the characterization of samples with non-voltage-dependent capacitance, such as very thin dielectric films, self-assembled monolayers and biological membranes, can provide new insight into the dielectric properties at the nanoscale

  19. Nanoscale capacitance imaging with attofarad resolution using ac current sensing atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fumagalli, L [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Ferrari, G [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Sampietro, M [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Casuso, I [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain); MartInez, E [Plataforma de Nanotecnologia, Parc Cientific de Barcelona, C/ Josep Samitier 1-5, 08028-Barcelona (Spain); Samitier, J [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain); Gomila, G [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain)

    2006-09-28

    Nanoscale capacitance imaging with attofarad resolution ({approx}1 aF) of a nano-structured oxide thin film, using ac current sensing atomic force microscopy, is reported. Capacitance images are shown to follow the topographic profile of the oxide closely, with nanometre vertical resolution. A comparison between experimental data and theoretical models shows that the capacitance variations observed in the measurements can be mainly associated with the capacitance probed by the tip apex and not with positional changes of stray capacitance contributions. Capacitance versus distance measurements further support this conclusion. The application of this technique to the characterization of samples with non-voltage-dependent capacitance, such as very thin dielectric films, self-assembled monolayers and biological membranes, can provide new insight into the dielectric properties at the nanoscale.

  20. Crystallographic Investigation of Ag (4 mol%) Doped ZnO (SZO) Thin Films by XRD

    International Nuclear Information System (INIS)

    Lwin Lwin Nwe; Sandar Dwe; Khant Khant Lin; Khin Thuzar; Than Than Win; Ko Ko Kyaw Soe

    2008-03-01

    Silver doped ZnO(SZO) thin films are prepared by sol-based method. The silver dopant concentration is 4 mol % in this case. XRD analysis carried out to determine, crystallographic properties such as lattice parameters and crystallite size of SZO thin films.

  1. Solid-state superionic stamping with silver iodide-silver metaphosphate glass

    International Nuclear Information System (INIS)

    Jacobs, K E; Hsu, K H; Han, X; Azeredo, B P; Ferreira, P M; Kumar, A; Fang, N X

    2011-01-01

    This paper demonstrates and analyzes the new use of the glassy solid electrolyte AgI-AgPO 3 for direct nanopatterning of thin silver films with feature resolutions of 30 nm. AgI-AgPO 3 has a high room temperature ionic conductivity with Ag + as the mobile ion, leading to silver etch/patterning rates of up to 20 nm s -1 at an applied bias of 300 mV. The glass can be melt-processed at temperatures below 200 deg. C, providing a facile and economical pathway for creating large area stamps, including the 25 mm 2 stamps shown in this study. Further, the glass is sufficiently transparent to permit integration with existing tools such as aligners and imprint tools, enabling high overlay registration accuracy and facilitating insertion into multi-step fabrication recipes.

  2. Synthesis and characterization of silver-polypyrrole film composite

    Energy Technology Data Exchange (ETDEWEB)

    Ayad, Mohamad M., E-mail: mayad12000@yahoo.com [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt); Zaki, Eman [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt)

    2009-11-15

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO{sub 3}. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO{sub 3} solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  3. Synthesis and characterization of silver-polypyrrole film composite

    International Nuclear Information System (INIS)

    Ayad, Mohamad M.; Zaki, Eman

    2009-01-01

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3 . Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  4. Synthesis and characterization of silver-polypyrrole film composite

    Science.gov (United States)

    Ayad, Mohamad. M.; Zaki, Eman

    2009-11-01

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  5. Atomic layer deposition: an enabling technology for the growth of functional nanoscale semiconductors

    Science.gov (United States)

    Biyikli, Necmi; Haider, Ali

    2017-09-01

    In this paper, we present the progress in the growth of nanoscale semiconductors grown via atomic layer deposition (ALD). After the adoption by semiconductor chip industry, ALD became a widespread tool to grow functional films and conformal ultra-thin coatings for various applications. Based on self-limiting and ligand-exchange-based surface reactions, ALD enabled the low-temperature growth of nanoscale dielectric, metal, and semiconductor materials. Being able to deposit wafer-scale uniform semiconductor films at relatively low-temperatures, with sub-monolayer thickness control and ultimate conformality, makes ALD attractive for semiconductor device applications. Towards this end, precursors and low-temperature growth recipes are developed to deposit crystalline thin films for compound and elemental semiconductors. Conventional thermal ALD as well as plasma-assisted and radical-enhanced techniques have been exploited to achieve device-compatible film quality. Metal-oxides, III-nitrides, sulfides, and selenides are among the most popular semiconductor material families studied via ALD technology. Besides thin films, ALD can grow nanostructured semiconductors as well using either template-assisted growth methods or bottom-up controlled nucleation mechanisms. Among the demonstrated semiconductor nanostructures are nanoparticles, nano/quantum-dots, nanowires, nanotubes, nanofibers, nanopillars, hollow and core-shell versions of the afore-mentioned nanostructures, and 2D materials including transition metal dichalcogenides and graphene. ALD-grown nanoscale semiconductor materials find applications in a vast amount of applications including functional coatings, catalysis and photocatalysis, renewable energy conversion and storage, chemical sensing, opto-electronics, and flexible electronics. In this review, we give an overview of the current state-of-the-art in ALD-based nanoscale semiconductor research including the already demonstrated and future applications.

  6. Electrodeposition of silver nanoparticle arrays on transparent conductive oxides

    International Nuclear Information System (INIS)

    Zhang, Dezhong; Tang, Yang; Jiang, Fuguo; Han, Zhihua; Chen, Jie

    2016-01-01

    Highlights: • The sliver nanoparticles' size and the distance between nanoparticles are tunable. - Abstract: In this paper, we present a facile method for the preparation of silver nanoparticles on aluminum-doped zinc oxide (AZO) via electrodeposition techniques at room temperature. The morphology and structure of silver nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. Due to localized surface plasmon resonances, as-prepared silver nanoparticles on AZO glass exhibited different reflectivity in contrast with bare AZO glass. The weighted reflection of AZO substrate increased from 10.2% to 12.8%. The high reflection property of silver nanoparticle arrays on AZO substrate might be applicable for thin film solar cells and other optoelectronics applications.

  7. Electrodeposition of silver nanoparticle arrays on transparent conductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dezhong; Tang, Yang, E-mail: tangyang@nicenergy.com; Jiang, Fuguo; Han, Zhihua; Chen, Jie

    2016-04-30

    Highlights: • The sliver nanoparticles' size and the distance between nanoparticles are tunable. - Abstract: In this paper, we present a facile method for the preparation of silver nanoparticles on aluminum-doped zinc oxide (AZO) via electrodeposition techniques at room temperature. The morphology and structure of silver nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. Due to localized surface plasmon resonances, as-prepared silver nanoparticles on AZO glass exhibited different reflectivity in contrast with bare AZO glass. The weighted reflection of AZO substrate increased from 10.2% to 12.8%. The high reflection property of silver nanoparticle arrays on AZO substrate might be applicable for thin film solar cells and other optoelectronics applications.

  8. Gilded Silver Mask

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    This gilded silver mask from the Liao Dynasty is 31 cm long and 22.2 cm wide. The plump oval face was designed with a protruding brow ridge, narrow eyes, high-bridged nose and closed mouth. The chin is slightly round against a thin neck, the ears are long and the hair can be clearly seen from the finely carved lines. The use of masks was recorded as

  9. Direct Probing of Polarization Charge at Nanoscale Level

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Owoong [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Seol, Daehee [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Lee, Dongkyu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Han, Hee [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Lindfors-Vrejoiu, Ionela [Univ. of Cologne (Germany). Physics Inst.; Lee, Woo [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Jesse, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Lee, Ho Nyung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Kalinin, Sergei V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Alexe, Marin [Univ. of Warwick, Coventry (United Kingdom). Dept. of Physics; Kim, Yunseok [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering

    2017-11-14

    Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long-term development of reducing the sizes of devices, the preparation of ferroelectric materials and devices is entering the nanometer-scale regime. In order to evaluate the ferroelectricity, there is a need to investigate the polarization charge at the nanoscale. Nonetheless, it is generally accepted that the detection of polarization charges using a conventional conductive atomic force microscopy (CAFM) without a top electrode is not feasible because the nanometer-scale radius of an atomic force microscopy (AFM) tip yields a very low signal-to-noise ratio. But, the detection is unrelated to the radius of an AFM tip and, in fact, a matter of the switched area. In this work, the direct probing of the polarization charge at the nanoscale is demonstrated using the positive-up-negative-down method based on the conventional CAFM approach without additional corrections or circuits to reduce the parasitic capacitance. The polarization charge densities of 73.7 and 119.0 µC cm-2 are successfully probed in ferroelectric nanocapacitors and thin films, respectively. The results we obtained show the feasibility of the evaluation of polarization charge at the nanoscale and provide a new guideline for evaluating the ferroelectricity at the nanoscale.

  10. Nano-structural characteristics and optical properties of silver chiral nano-flower sculptured thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Haydari-Nasab, Fatemh; Malmir, Mariam [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of)

    2011-08-15

    Silver chiral nano-flowers with 3-, 4- and 5-fold symmetry were produced using oblique angle deposition method in conjunction with the rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM), were employed to obtain morphology and nano-structure of the films. Optical characteristics of silver chiral nano-flower thin films were obtained using single beam spectrophotometer with both s- and p-polarization incident light at 30{sup o} and 70{sup o} incidence angles and at different azimuthal angles ({phi}). Optical spectra showed both TM (TDM (transverse dipole mode) and TQM (transverse quadruple mode)) and LM (longitudinal mode) Plasmon resonance peaks. For 3- and 4-fold symmetry chiral nano-flowers the s-polarization extinction spectra obtained at different azimuthal angles did not show significant change in the Plasmon peak position while 5-fold symmetry chiral nano-flower showed a completely different behavior, which may be the result of increased surface anisotropy, so when the {phi} angle is changed the s-polarization response from the surface can change more significantly than that for lower symmetries. In general, for 3-, 4- and 5-fold symmetry chiral nano-flowers a sharp peak at lower wavelengths (<450 nm) is observed in the s-polarization spectra, while in addition to this peak a broad peak at longer wavelengths (i.e., LM) observed in the p-polarization spectra, which is more dominant for 70{sup o} incidence angle.

  11. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  12. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe; Lu, Xinglin; Bar-Zeev, Edo; Zodrow, Katherine R.; Nejati, Siamak; Qi, Genggeng; Giannelis, Emmanuel P.; Elimelech, Menachem

    2014-01-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  13. Silver removal process development for the MEO cleanout

    International Nuclear Information System (INIS)

    Hsu, P.C.; Chiba, Z.; Schumacher, B.J.; Murguia, L.C.; Adamson, M.G.

    1996-02-01

    The Mediated Electrochemical Oxidation (MEO) system is an aqueous process which treats low-level mixed wastes by oxidizing the organic components of he waste into carbon dioxide and water. As MEO system continues to run, dissolved ash and radionuclides slowly accumulate in the anolyte and must be removed to maintain process efficiency. At such time, all of the anolyte is pumped into a still feed tank, and the silver ions need to be removed before sending the solution to a thin-film evaporator for further concentration. The efficiency of removing silver ions in the solution needs to be high enough such that the residual silver sent to Final Forms would be less than 1% wt. The purpose of this work is to develop an efficient process to remove silver ions during the MEO cleanout and to demonstrate the capability of centrifugation for separating small silver chloride particles from the solution. This development work includes lab scale experiments and bench scale tests. This report summarizes the results

  14. In situ SU-8 silver nanocomposites

    Directory of Open Access Journals (Sweden)

    Søren V. Fischer

    2015-07-01

    Full Text Available Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution to this problem, an easy new method of fabricating silver nanocomposites by an in situ reduction of precursors within the epoxy-based photoresist SU-8 has been developed. AgNO3 dissolved in acetonitrile and mixed with the epoxy-based photoresist SU-8 forms silver nanoparticles primarily during the pre- and post-exposure soft bake steps at 95 °C. A further high-temperature treatment at 300 °C resulted in the formation of densely homogeneously distributed silver nanoparticles in the photoresist matrix. No particle growth or agglomeration of nanoparticles is observed at this point. The reported new in situ silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5 µm is achieved in the lithographic process. The UV exposure time is found to be independent of the nanoparticle concentration. The fabricated silver nanocomposites exhibit high plasmonic responses suitable for the development of new optoelectronic and optical sensing devices.

  15. Finite gratings of many thin silver nanostrips: Optical resonances and role of periodicity

    Directory of Open Access Journals (Sweden)

    Olga V. Shapoval

    2013-04-01

    Full Text Available We study numerically the optical properties of the periodic in one dimension flat gratings made of multiple thin silver nanostrips suspended in free space. Unlike other publications, we consider the gratings that are finite however made of many strips that are well thinner than the wavelength. Our analysis is based on the combined use of two techniques earlier verified by us in the scattering by a single thin strip of conventional dielectric: the generalized (effective boundary conditions (GBCs imposed on the strip median lines and the Nystrom-type discretization of the associated singular and hyper-singular integral equations (IEs. The first point means that in the case of the metal strip thickness being only a small fraction of the free-space wavelength (typically 5 nm to 50 nm versus 300 nm to 1 μm we can neglect the internal field and consider only the field limit values. In its turn, this enables reduction of the integration contour in the associated IEs to the strip median lines. This brings significant simplification of the scattering analysis while preserving a reasonably adequate modeling. The second point guarantees fast convergence and controlled accuracy of computations that enables us to compute the gratings consisting of hundreds of thin strips, with total size in hundreds of wavelengths. Thanks to this, in the H-polarization case we demonstrate the build-up of sharp grating resonances (a.k.a. as collective or lattice resonances in the scattering and absorption cross-sections of sparse multi-strip gratings, in addition to better known localized surface-plasmon resonances on each strip. The grating modes, which are responsible for these resonances, have characteristic near-field patterns that are distinctively different from the plasmons as can be seen if the strip number gets larger. In the E-polarization case, no such resonances are detectable however the build-up of Rayleigh anomalies is observed, accompanied by the reduced

  16. Characterization of n-TiO2 thin films modified with silver nanoparticles

    International Nuclear Information System (INIS)

    Cueto, L.F.; Sanchez-Cervantes, E.M.

    2010-01-01

    Carbon dioxide accumulation in the atmosphere has gained much attention and has reopened many research lines that initiated two or three decades ago. Electrochemical reduction represents one of the most discussed methods, especially where semiconductor and metal-semiconductor cathodes are used to achieve CO 2 transformation into higher-energy products. In the present work, the influence of silver nanoparticles upon CO 2 reduction on n-TiO 2 cathodes in aqueous media is presented. Silver nanoparticles with an average diameter of 250nm were deposited on n-TiO 2 surfaces by the electrochemical Double-Pulse Potential method. A Grazing-Incidence X-Ray Diffraction structural analysis is presented showing the presence of metallic silver, while Atomic Force Microscopy shows surface roughness and particle size before and after surface modification. These measurements were confirmed by Scanning-Electron Microscopy acquainting for the formation of metal particles on the n-TiO 2 surface. Enhancement of CO 2 reduction by the presence of silver on cathodes is shown by cyclic voltammetry. (author)

  17. Mechanical Characterization of Polydopamine-Assisted Silver Deposition on Polymer Substrates

    Science.gov (United States)

    Cordes, Amanda Laurence

    Inspired by the adhesive proteins in marine mussels, polydopamine has become a popular adhesive ad-layer for surface functionalization of a variety of substrates. Based on the chemistry of the dopamine monomer, amine and thiol functional groups are hypothesized to increase adhesion between polymer substrates and polydopamine thin films. This hypothesis was the central motivation for development of a tailorable thiol-ene system in order to study the effects of substrate chemistry on polydopamine adhesion. While polydopamine-adhered silver has been studied on a variety of substrates, no in depth mechanical characterization has been performed and to date, no research has been published on thiol-enes coated in polydopamine-adhered silver. The purpose of this study was to characterize the mechanical durability and adhesion properties of a polydopamine-adhered silver film on commercial substrates and a tailorable thiol-ene system. Polydopamine and silver coatings were deposited on a variety of polymer substrates through a simple dip-coat process. The polydopamine forms a thin uniform adhesive layer and the silver deposits in a discontinuous manner with a nanoparticle sized base layer covering the full surface and micron-sized clusters adhered sporadically on top. Mechanical tensile testing was performed to characterize the durability of the silver coating on commercial polymers. Coated nylon and HDPE showed no signs of degradation or delamination of the polydopamine-adhered silver coating up to 30% strain although both substrates showed large plastic deformation. Peel tests were performed on both commercial polymers as well as a tailorable thiol-ene system. Results support the hypothesis that polydopamine adhesion is increased with the presence of functional groups. Parts of the HDPE sample were cleanly peeled, but silver patches were left sporadically across the surface pointing to weaker adhesion between polyethylene and polydopamine. A high adhesive strength tape was

  18. Silver electrocrystallization at polyaniline-coated electrodes

    International Nuclear Information System (INIS)

    Ivanov, S.; Tsakova, V.

    2004-01-01

    The initial stage of silver electrocrystallization is studied at polyaniline (PANI)-coated platinum electrodes by means of potentiostatic current transients and electron microscopic observations. Data for the nucleation frequency and the number of active sites for nucleation are obtained by interpreting of current transients according to the theory for nucleation and 3D growth under diffusion limitations. It is found that depending on the PANI layers thickness, d, two different regimes for silver nucleation and growth exist. For thin PANI coatings (d 0.3 μm), silver nucleation occurs with a two orders of magnitude lower nucleation frequency at active sites located most probably at the polymer surface, their number remaining constant for thicknesses up to 1.4 μm. It is established that reduction of the PANI layer occurring in parallel with the silver electrodeposition does not influence the number of active sites for nucleation. The results obtained by interpretation of current transients are in good agreement with results for the number of crystals obtained by microscopic observation

  19. Properties of Bulk Sintered Silver As a Function of Porosity

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL; Wang, Hsin [ORNL; Ferber, Mattison K [ORNL; Liang, Zhenxian [ORNL

    2012-06-01

    This report summarizes a study where various properties of bulk-sintered silver were investigated over a range of porosity. This work was conducted within the National Transportation Research Center's Power Device Packaging project that is part of the DOE Vehicle Technologies Advanced Power Electronics and Electric Motors Program. Sintered silver, as an interconnect material in power electronics, inherently has porosity in its produced structure because of the way it is made. Therefore, interest existed in this study to examine if that porosity affected electrical properties, thermal properties, and mechanical properties because any dependencies could affect the intended function (e.g., thermal transfer, mechanical stress relief, etc.) or reliability of that interconnect layer and alter how its performance is modeled. Disks of bulk-sintered silver were fabricated using different starting silver pastes and different sintering conditions to promote different amounts of porosity. Test coupons were harvested out of the disks to measure electrical resistivity and electrical conductivity, thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and yield stress. The authors fully recognize that the microstructure of processed bulk silver coupons may indeed not be identical to the microstructure produced in thin (20-50 microns) layers of sintered silver. However, measuring these same properties with such a thin actual structure is very difficult, requires very specialized specimen preparation and unique testing instrumentation, is expensive, and has experimental shortfalls of its own, so the authors concluded that the herein measured responses using processed bulk sintered silver coupons would be sufficient to determine acceptable values of those properties. Almost all the investigated properties of bulk sintered silver changed with porosity content within a range of 3-38% porosity. Electrical resistivity, electrical conductivity

  20. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    International Nuclear Information System (INIS)

    Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; Benthem, Klaus van

    2016-01-01

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO_3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  1. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hihath, Sahar [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Department of Physics, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Santala, Melissa K.; Campbell, Geoffrey [Materials Science Division, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Benthem, Klaus van, E-mail: benthem@ucdavis.edu [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States)

    2016-08-28

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO{sub 3} substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  2. Oxygen content modulation by nanoscale chemical and electrical patterning in epitaxial SrCoO3-δ (0 < δ ≤ 0.5) thin films

    Science.gov (United States)

    Hu, S.; Seidel, J.

    2016-08-01

    Fast controllable redox reactions in solid materials at room temperature are a promising strategy for enhancing the overall performance and lifetime of many energy technology materials and devices. Easy control of oxygen content is a key concept for the realisation of fast catalysis and bulk diffusion at room temperature. Here, high quality epitaxial brownmillerite SrCoO2.5 thin films have been oxidised to perovskite (P) SrCoO3 with NaClO. X-ray diffraction, scanning probe microscopy and x-ray photoelectron spectroscopy measurements were performed to investigate the structural and electronic changes of the material. The oxidised thin films were found to exhibit distinct morphological changes from an atomically flat terrace structure to forming small nanosized islands with boundaries preferentially in [100] or [010] directions all over the surface, relaxing the in-plane strain imposed by the substrate. The conductivity, or oxygen content, of each single island is confined by these textures, which can be locally patterned even further with electric poling. The high charging level at the island boundaries indicates a magnified electric capacity of SCO thin films, which could be exploited in future device geometries. This finding represents a new way of oxygen modulation with associated self-assembled charge confinement to nanoscale boundaries, offering interesting prospects in nanotechnology applications.

  3. Phonon transport across nano-scale curved thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mansoor, Saad B.; Yilbas, Bekir S., E-mail: bsyilbas@kfupm.edu.sa

    2016-12-15

    Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

  4. Phonon transport across nano-scale curved thin films

    International Nuclear Information System (INIS)

    Mansoor, Saad B.; Yilbas, Bekir S.

    2016-01-01

    Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

  5. Thermal conductivity of nanoscale thin nickel films

    Institute of Scientific and Technical Information of China (English)

    YUAN Shiping; JIANG Peixue

    2005-01-01

    The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T = 300 K, which is lower than the Debye temperature ()D = 450 K,the results show that in a film thickness range of about 1-11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.

  6. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    International Nuclear Information System (INIS)

    Marciano, F.R.; Bonetti, L.F.; Pessoa, R.S.; Massi, M.; Santos, L.V.; Trava-Airoldi, V.J.

    2009-01-01

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  7. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Marciano, F.R., E-mail: fernanda@las.inpe.b [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil); Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Bonetti, L.F. [Clorovale Diamantes Industria e Comercio Ltda, Estr. do Torrao de Ouro, 500-Sao Jose dos Campos, 12229-390, SP (Brazil); Pessoa, R.S.; Massi, M. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Santos, L.V.; Trava-Airoldi, V.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil)

    2009-08-03

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  8. AFM and XRD characterization of silver nanoparticles films deposited on the surface of DGEBA epoxy resin by ion sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Jose Elisandro de; Machado, Rogerio; Macedo, Marcelo Andrade; Cunha, Frederico Guilherme Carvalho [Clinica de Medicina Nuclear e Radiologia de Maceio (MedRadiUS), Radiology and Imaging Diagnosis at Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil)

    2012-07-01

    In this work, silver atoms were deposited by ion sputtering on the surface of diglycidyl ether of bisphenol A (DGEBA) epoxy resin cured at 150 deg C for 6 hours in air. The films of DGEBA and its precursors were characterized by Raman spectroscopy to identify the main functional groups and their relationship with the deposited silver atoms. Silver thin films of 5, 10, 15 and 20 nm were deposited on the epoxy resin at room temperature. Both the initial film of DGEBA and the subsequent silver thin film were analyzed by Atomic Force Microscopy (AFM) in the non-contact mode. Silver thin films were also analyzed using X-ray diffraction (XRD) at room temperature. The AFM results showed the formation of silver crystallites on the surface of DGEBA at very low coverage whereas XRD indicated that most of them had their main axis aligned to the normal of the surface. An increase in the coverage led to an increase in the grain size as indicated by AFM. However, XRD results indicated that the crystallite size remained almost constant while the appearance of peaks corresponding to other crystalline orientations suggests the coalescence of the original crystallites and an increase in size of the more dense planes, namely [111]. (author)

  9. AFM and XRD characterization of silver nanoparticles films deposited on the surface of DGEBA epoxy resin by ion sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Jose Elisandro de; Machado, Rogerio; Macedo, Marcelo Andrade [Universidade Federal de Sergipe (UFSE), Aracaju, SE (Brazil). Programa de Pos-graduacao em Fisica; Cunha, Frederico Guilherme Carvalho [Universidade Federal de Sergipe (UFSE), Aracaju, SE (Brazil). Programa de Pos-graduacao em Ciencia e Engenharia de Materiais

    2012-07-01

    In this work, silver atoms were deposited by ion sputtering on the surface of diglycidyl ether of bisphenol A (DGEBA) epoxy resin cured at 150 Degree-Sign C for 6 hours in air. The films of DGEBA and its precursors were characterized by Raman spectroscopy to identify the main functional groups and their relationship with the deposited silver atoms. Silver thin films of 5, 10, 15 and 20 nm were deposited on the epoxy resin at room temperature. Both the initial film of DGEBA and the subsequent silver thin film were analyzed by Atomic Force Microscopy (AFM) in the non-contact mode. Silver thin films were also analyzed using X-ray diffraction (XRD) at room temperature. The AFM results showed the formation of silver crystallites on the surface of DGEBA at very low coverage whereas XRD indicated that most of them had their main axis aligned to the normal of the surface. An increase in the coverage led to an increase in the grain size as indicated by AFM. However, XRD results indicated that the crystallite size remained almost constant while the appearance of peaks corresponding to other crystalline orientations suggests the coalescence of the original crystallites and an increase in size of the more dense planes, namely [111]. (author)

  10. AFM and XRD characterization of silver nanoparticles films deposited on the surface of DGEBA epoxy resin by ion sputtering

    Directory of Open Access Journals (Sweden)

    José Elisandro de Andrade

    2013-01-01

    Full Text Available In this work, silver atoms were deposited by ion sputtering on the surface of diglycidyl ether of bisphenol A (DGEBA epoxy resin cured at 150 °C for 6 hours in air. The films of DGEBA and its precursors were characterized by Raman spectroscopy to identify the main functional groups and their relationship with the deposited silver atoms. Silver thin films of 5, 10, 15 and 20 nm were deposited on the epoxy resin at room temperature. Both the initial film of DGEBA and the subsequent silver thin film were analyzed by Atomic Force Microscopy (AFM in the non-contact mode. Silver thin films were also analyzed using X-ray diffraction (XRD at room temperature. The AFM results showed the formation of silver crystallites on the surface of DGEBA at very low coverage whereas XRD indicated that most of them had their main axis aligned to the normal of the surface. An increase in the coverage led to an increase in the grain size as indicated by AFM. However, XRD results indicated that the crystallite size remained almost constant while the appearance of peaks corresponding to other crystalline orientations suggests the coalescence of the original crystallites and an increase in size of the more dense planes, namely [111].

  11. Versatile Molecular Silver Ink Platform for Printed Flexible Electronics.

    Science.gov (United States)

    Kell, Arnold J; Paquet, Chantal; Mozenson, Olga; Djavani-Tabrizi, Iden; Deore, Bhavana; Liu, Xiangyang; Lopinski, Gregory P; James, Robert; Hettak, Khelifa; Shaker, Jafar; Momciu, Adrian; Ferrigno, Julie; Ferrand, Olivier; Hu, Jian Xiong; Lafrenière, Sylvie; Malenfant, Patrick R L

    2017-05-24

    A silver molecular ink platform formulated for screen, inkjet, and aerosol jet printing is presented. A simple formulation comprising silver neodecanoate, ethyl cellulose, and solvent provides improved performance versus that of established inks, yet with improved economics. Thin, screen-printed traces with exceptional electrical (molecular ink platform enables an aerosol jet-compatible ink that yields conductive features on glass with 2× bulk resistivity and strong adhesion to various plastic substrates. An inkjet formulation is also used to print top source/drain contacts and demonstrate printed high-mobility thin film transistors (TFTs) based on semiconducting single-walled carbon nanotubes. TFTs with mobility values of ∼25 cm 2 V -1 s -1 and current on/off ratios >10 4 were obtained, performance similar to that of evaporated metal contacts in analogous devices.

  12. Nanoscale TiO2 films and their application in remediation of organic pollutants

    Science.gov (United States)

    Photocatalysis is an advanced process for treatment of air, wastewater, and drinking water, the primary advantage being its ability to mineralize many pollutants. Among several nanoscale arrangements of photocatalysts, there has been a strong push to develop them as thin films be...

  13. Effect of content silver and heat treatment temperature on morphological, optical, and electrical properties of ITO films by sol-gel technique

    Science.gov (United States)

    Mirzaee, Majid; Dolati, Abolghasem

    2014-09-01

    Silver-doped indium tin oxide thin films were synthesized using sol-gel dip-coating technique. The influence of different silver-dopant contents and annealing temperature on the electrical, optical, structural, and morphological properties of the films were characterized by means of four-point probe, UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscope (XPS). XRD analysis confirmed the formation of cubic bixbyte structure of In2O3 with silver nanoparticles annealed at 350 °C. XPS analysis showed that divalent tin transformed to tetravalent tin through oxidization, and silver nanoparticles embedded into ITO matrix covered with silver oxide shell, resulting in high quality nanocomposite thin films. The embedment of polyvinylpyrrolidone inhibited the growth of silver nanoparticles and ITO annealed at 350 °C. Delafossite structure of tin-doped AgInO2 was found at higher annealing temperatures. XRD analysis and FESEM micrographs showed that the optimum temperature to prevent the formation of AgInO2 is 350 °C. The embedment of silver particles (5-10 nm) from reduction of silver ion in ITO thin films improved the electrical conductivity and optical transmittance of ITO nanolayers. The lowest stable sheet resistance of 1,952 Ω/Sq for a 321 nm thick and an average optical transmittance of 91.8 % in the visible region with a band gap of 3.43 eV were achieved for silver-doping content of 0.04 M.

  14. Can a novel silver nano coating reduce infections and maintain cell viability in vitro?

    Science.gov (United States)

    Qureshi, Ammar T; Landry, Jace P; Dasa, Vinod; Janes, Marlene; Hayes, Daniel J

    2014-03-01

    Herein we report a facile layer-by-layer method for creating an antimicrobial coating composed of silver nanoparticles on medical grade titanium test discs. Nanoscale silver nanoparticle layers are attached to the titanium orthopedic implant material via aminopropyltriethoxy silane crosslinker that reacts with neighboring silane moieties to create an interconnected network. A monolayer of silane, followed by a monolayer of silver nanoparticles would form one self-assembled layer and this process can be repeated serially, resulting in increased silver nanoparticles deposition. The release rate of silver ion increases predictably with increasing numbers of layers and at appropriate thicknesses these coatings demonstrate 3-4 log reduction of viable Escherichia coli and Staphylococcus aureus bacteria. Increasing the thickness of the coatings resulted in reduced bacterial colonization as determined by fluorescent staining and image analysis. Interestingly, the cytotoxicity of murine 3T3 cells as quantified by fluorescent staining and flow cytometry, was minimal and did not vary significantly with the coating thickness. Additionally, these coatings are mechanically stable and resist delamination by orthogonal stress test. This simple layer-by-layer coating technique may provide a cost-effective and biocompatible method for reducing microbial colonization of implantable orthopedic devices.

  15. Complex conductivity response to silver nanoparticles in partially saturated sand columns

    Science.gov (United States)

    Abdel Aal, Gamal; Atekwana, Estella A.; Werkema, D. Dale

    2017-02-01

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0-30%), nanoparticle concentrations (0-10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90-210 and 1500-2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex conductivity parameters based on the strong power law relationships.

  16. Quantum dot-based local field imaging reveals plasmon-based interferometric logic in silver nanowire networks.

    Science.gov (United States)

    Wei, Hong; Li, Zhipeng; Tian, Xiaorui; Wang, Zhuoxian; Cong, Fengzi; Liu, Ning; Zhang, Shunping; Nordlander, Peter; Halas, Naomi J; Xu, Hongxing

    2011-02-09

    We show that the local electric field distribution of propagating plasmons along silver nanowires can be imaged by coating the nanowires with a layer of quantum dots, held off the surface of the nanowire by a nanoscale dielectric spacer layer. In simple networks of silver nanowires with two optical inputs, control of the optical polarization and phase of the input fields directs the guided waves to a specific nanowire output. The QD-luminescent images of these structures reveal that a complete family of phase-dependent, interferometric logic functions can be performed on these simple networks. These results show the potential for plasmonic waveguides to support compact interferometric logic operations.

  17. Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

    Directory of Open Access Journals (Sweden)

    A. C. Nwanya

    2013-01-01

    Full Text Available Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3 precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

  18. EGaIn-Assisted Room-Temperature Sintering of Silver Nanoparticles for Stretchable, Inkjet-Printed, Thin-Film Electronics.

    Science.gov (United States)

    Tavakoli, Mahmoud; Malakooti, Mohammad H; Paisana, Hugo; Ohm, Yunsik; Marques, Daniel Green; Alhais Lopes, Pedro; Piedade, Ana P; de Almeida, Anibal T; Majidi, Carmel

    2018-05-29

    Coating inkjet-printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six-orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room-temperature "sintering" process in which the liquid-phase EGaIn alloy binds the AgNP particles (≈100 nm diameter) to form a continuous conductive trace. Ultrathin and hydrographically transferrable electronics are produced by printing traces with a composition of AgNP-Ga-In on a 5 µm-thick temporary tattoo paper. The printed circuit is flexible enough to remain functional when deformed and can support strains above 80% with modest electromechanical coupling (gauge factor ≈1). These mechanically robust thin-film circuits are well suited for transfer to highly curved and nondevelopable 3D surfaces as well as skin and other soft deformable substrates. In contrast to other stretchable tattoo-like electronics, the low-cost processing steps introduced here eliminate the need for cleanroom fabrication and instead requires only a commercial desktop printer. Most significantly, it enables functionalities like "electronic tattoos" and 3D hydrographic transfer that have not been previously reported with EGaIn or EGaIn-based biphasic electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Host thin films incorporating nanoparticles

    Science.gov (United States)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  20. Mechanical characterization of solution-derived nanoparticle silver ink thin films

    International Nuclear Information System (INIS)

    Greer, Julia R.; Street, Robert A.

    2007-01-01

    Mechanical properties of sintered silver nanoparticles are investigated via substrate curvature and nanoindentation methods. Substrate curvature measurements reveal that permanent microstructural changes occur during initial heating while subsequent annealing results in nearly elastic behavior of the thinner films. Thicker films were found to crack upon thermal treatment. The coefficient of thermal expansion was determined from linear slopes of curvature curves to be 1.9±0.097 ppm/ degree sign C, with elastic modulus and hardness determined via nanoindentation. Accounting for substrate effects, nanoindentation hardness and modulus remained constant for different film thicknesses and did not appear to be a function of annealing conditions. Hardness of 0.91 GPa and modulus of 110 GPa are somewhat lower than expected for a continuous nanocrystalline silver film, most likely due to porosity

  1. Engineering Nanoscale Multiferroic Composites for Memory Applications with Atomic Layer Deposition of Pb(ZrxTi1-x)O3 Thin Films

    Science.gov (United States)

    Chien, Diana

    This work focuses on the development of atomic layer deposition (ALD) for lead zirconate titanate, Pb(ZrxTi1-x)O 3 (PZT). Leveraging the surface-reaction controlled process based on alternating self-limiting surface reactions, PZT can be synthesized not only with elemental precision to realize the desired composition (Zr/Ti = 52/48) but also with outstanding conformality. The latter enables the integration of PZT with a ferromagnetic phase to realize multiferroism (MF) and magnetoelectric (ME) effect. Since PZT is one of the best known ferroelectric and piezoelectric materials due the large displacements of the Pb ions at the morphotropic phase boundary, PZT based MF composites could lead to stronger ME coupling through strain coupling at the interface. Specifically, ALD PZT thin films were synthesized by using beta-diketonate metalorganic precursors Pb(TMHD)2, Zr(TMHD)4, and Ti(O.i-Pr) 2(TMHD)2 and H2O. The number of local cycles and global cycles were regulated to achieve the desired stoichiometry and thickness, respectively. ALD of PZT was studied to obtain (100) textured PZT on Pt (111) oriented platinized silicon substrates. In order to attain a highly oriented PZT thin film, a (100) textured PbTiO3 seed layer was required because PZT orientation is governed by nucleation. MF nanocomposites were engineered using ALD PZT thin films to achieve controlled complex nanoscale structures, enabling porosity to be studied as a new additional parameter for nanocomposite architectures to enhance ME effect. Specifically, 3--6 nm-thick ALD PZT thin films were deposited to uniformly coat the walls of mesoporous cobalt ferrite (CFO) template. The PZT/CFO nanocomposites were electrically poled ex-situ and the change in magnetic moment was measured. The inverse magnetoelectric coupling coefficient, a, was determined to be 85.6 Oe-cm/mV. The in-plane results show no significant change in magnetization (1--4%) as a function of electric field, which was expected due to the effect

  2. Fabrication of Au/graphene oxide/Ag sandwich structure thin film and its tunable energetics and tailorable optical properties

    OpenAIRE

    Ruijin Hong; Jialin Ji; Chunxian Tao; Daohua Zhang; Dawei Zhang

    2017-01-01

    Au/graphene oxide/Ag sandwich structure thin film was fabricated. The effects of graphene oxide (GO) and bimetal on the structure and optical properties of metal silver films were investigated by X-ray diffraction (XRD), optical absorption, and Raman intensity measurements, respectively. Compared to silver thin film, Au/graphene oxide/Ag sandwich structure composite thin films were observed with wider optical absorption peak and enhanced absorption intensity. The Raman signal for Rhodamine B ...

  3. Electrochemical study of the tarnish layer of silver deposited on glass

    OpenAIRE

    Ben Amor , Yasser; Sutter , Eliane; Takenouti , Hisasi; Tribollet , Bernard; Boinet , M.; Faure , R.; Balencie , J.; Durieu , G.

    2014-01-01

    International audience; Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the tarnished thin layer of silver deposited on glass. Instead of natural tarnishing in air environment, an acceleration of tarnishing process was realized by immersion of Ag covered glass in 10 μM K2S medium. The X-ray photoelectron spectroscopy (XPS) shows that tarnishing product formed on the silver surface consisted of Ag2S and Ag2O. As electrochemical characterizatio...

  4. Nanoscale hotspots due to nonequilibrium thermal transport

    International Nuclear Information System (INIS)

    Sinha, Sanjiv; Goodson, Kenneth E.

    2004-01-01

    Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

  5. Optical response of heterogeneous polymer layers containing silver nanostructures

    Directory of Open Access Journals (Sweden)

    Miriam Carlberg

    2017-05-01

    Full Text Available This work is focused on the study of the optical properties of silver nanostructures embedded in a polymer host matrix. The introduction of silver nanostructures in polymer thin films is assumed to result in layers having adaptable optical properties. Thin film layers with inclusions of differently shaped nanoparticles, such as nanospheres and nanoprisms, and of different sizes, are optically characterized. The nanoparticles are produced by a simple chemical synthesis at room temperature in water. The plasmonic resonance peaks of the different colloidal solutions range from 390 to 1300 nm. The non-absorbing, transparent polymer matrix poly(vinylpyrrolidone (PVP was chosen because of its suitable optical and chemical properties. The optical studies of the layers include spectrophotometry and spectroscopic ellipsometry measurements, which provide information about the reflection, transmission, absorption of the material as well as the complex optical indices, n and k. Finite difference time domain simulations of nanoparticles in thin film layers allow the visualization of the nanoparticle interactions or the electric field enhancement on and around the nanoparticles to complete the optical characterization. A simple analysis method is proposed to obtain the complex refractive index of nanospheres and nanoprisms in a polymer matrix.

  6. Direct synthesis of silver nanoparticles in ionic liquid

    International Nuclear Information System (INIS)

    Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F.

    2016-01-01

    Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract

  7. Direct synthesis of silver nanoparticles in ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F., E-mail: ffcamilo@unifesp.br [Universidade Federal de São Paulo, Laboratório de Materiais Híbridos, Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas (Brazil)

    2016-05-15

    Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract.

  8. Holographic investigation of silver electromigration in nano-sized As2S3 films

    Science.gov (United States)

    Sainov, S.; Todorov, R.; Bodurov, I.; Yovcheva, Temenuzhka

    2013-10-01

    Holographic gratings with a diffraction efficiency (DE) greater than 8% and a spatial resolution of 2237 mm-1 are recorded in very thin As2S3 films with a thickness of 100 nm. Silver photo-diffusion is observed during the holographic recording process while applying a corona discharge. We use the method of holographic grating relaxation spectroscopy (forced Rayleigh scattering) based on the evanescent waves to determine that the silver diffusion coefficient in the thin As2S3 film is in the range of (0.9-10.3) × 10-13 cm2 s-1 depending on the corona charge polarity. This work is dedicated to the 90th anniversary of the birth of Academician Jordan Malinowski.

  9. SERS activity of silver and gold nanostructured thin films deposited by pulsed laser ablation

    Science.gov (United States)

    Agarwal, N. R.; Tommasini, M.; Fazio, E.; Neri, F.; Ponterio, R. C.; Trusso, S.; Ossi, P. M.

    2014-10-01

    Nanostructured Au and Ag thin films were obtained by nanosecond pulsed laser ablation in presence of a controlled Ar atmosphere. Keeping constant other deposition parameters such as target-to-substrate distance, incidence angle, laser wavelength and laser fluence, the film morphology, revealed by SEM, ranges from isolated NPs to island structures and sensibly depends on gas pressure (10-100 Pa) and on the laser pulse number (500-3 × 10). The control of these two parameters allows tailoring the morphology and correspondingly the optical properties of the films. The position and width of the surface plasmon resonance peak, in fact, can be varied with continuity. The films showed remarkable surface-enhanced Raman activity (SERS) that depends on the adopted deposition conditions. Raman maps were acquired on micrometer-sized areas of both silver and gold substrates selected among those with the strongest SERS activity. Organic dyes of interest in cultural heritage studies (alizarin, purpurin) have been also considered for bench marking the substrates produced in this work. Also the ability to detect the presence of biomolecules was tested using lysozyme in a label free configuration.

  10. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma

    International Nuclear Information System (INIS)

    Palacios, J.C.; Chavez, J.A.; Olayo, M.G.; Cruz, G.J.

    2007-01-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  11. Ageing of plasma-mediated coatings with embedded silver nanoparticles on stainless steel: An XPS and ToF-SIMS investigation

    Science.gov (United States)

    Zanna, S.; Saulou, C.; Mercier-Bonin, M.; Despax, B.; Raynaud, P.; Seyeux, A.; Marcus, P.

    2010-09-01

    Nanocomposite thin films (˜170 nm), composed of silver nanoparticles enclosed in an organosilicon matrix, were deposited onto stainless steel, with the aim of preventing biofilm formation. The film deposition was carried out under cold plasma conditions, combining radiofrequency (RF) glow discharge fed with argon and hexamethyldisiloxane and simultaneous silver sputtering. XPS and ToF-SIMS were used to characterize Ag-organosilicon films in native form and after ageing in saline solution (NaCl 0.15 M), in order to further correlate their lifetime with their anti-fouling properties. Two coatings with significantly different silver contents (7.5% and 20.3%) were tested. Surface analysis confirmed the presence of metallic silver in the pristine coating and revealed significant modifications after immersion in the saline solution. Two different ageing mechanisms were observed, depending on the initial silver concentration in the film. For the sample exhibiting the low silver content (7.5%), the metal amount decreased at the surface in contact with the solution, due to the release of silver from the coating. As a result, after a 2-day exposure, silver nanoparticles located at the extreme surface were entirely released, whereas silver is still present in the inner part of the film. The coating thickness was not modified during ageing. In contrast, for the high silver content film (20.3%), the thickness decreased with immersion time, due to significant silver release and matrix erosion, assigned to a percolation-like effect. However, after 18 days of immersion, the delamination process stopped and a thin strongly bounded layer remained on the stainless steel surface.

  12. synthesis and optical characterization of acid-doped polyaniline thin

    African Journals Online (AJOL)

    HOD

    SYNTHESIS AND OPTICAL CHARACTERIZATION OF ACID-DOPED. POLYANILINE THIN .... MATERIALS AND METHODS .... Characterization of Se Doped Polyaniline”,Current. Applied ... with Silver Nanoparticles”, Advances in Materials.

  13. Molecular dynamics simulation about porous thin-film growth in secondary deposition

    International Nuclear Information System (INIS)

    Chen Huawei; Tieu, A. Kiet; Liu Qiang; Hagiwara, Ichiro; Lu Cheng

    2007-01-01

    The thin film growth has been confirmed to be assembled by an enormous number of clusters in experiments of CVD. Sequence of clusters' depositions proceeds to form the thin film at short time as gas fluids through surface of substrate. In order to grow condensed thin film using series of cluster deposition, the effect of initial velocity, substrate temperature and density of clusters on property of deposited thin film, especially appearance of nanoscale pores inside thin film must be investigated. In this simulation, three different cluster sizes of 203, 653, 1563 atoms with different velocities (0, 10, 100, 1000 and 3000 m/s) were deposited on a Cu(0 0 1) substrate whose temperatures were set between 300 and 1000 K. Four clusters and one cluster were used in primary deposition and secondary deposition, respectively. We have clarified that adhesion between clusters and substrate is greatly influenced by initial velocity. As a result, the exfoliation pattern of deposited thin film is dependent on initial velocity and different between them. One borderline dividing whole region into porous region and nonporous region are obtained to show the effect of growth conditions on appearance of nanoscale pores inside thin film. Moreover, we have also shown that the likelihood of porous thin film is dependent on the point of impact of a cluster relative to previously deposited clusters

  14. Molecular dynamics simulation about porous thin-film growth in secondary deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen Huawei [School of Mechanical Engineering and Automation, Beihang University, No. 37 Xuyuan Road, Haidian District, Beijing (China) and Mechanical Materials and Mechatronic Engineering, University of Wollongong, Northfields Avenue, NSW 2522 (Australia)]. E-mail: chen_hua_wei@yahoo.com; Tieu, A. Kiet [Mechanical Materials and Mechatronic Engineering, University of Wollongong, Northfields Avenue, NSW 2522 (Australia); Liu Qiang [School of Mechanical Engineering and Automation, Beihang University, No. 37 Xuyuan Road, Haidian District, Beijing (China); Hagiwara, Ichiro [Department of Mechanical Sciences and Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo (Japan); Lu Cheng [Mechanical Materials and Mechatronic Engineering, University of Wollongong, Northfields Avenue, NSW 2522 (Australia)

    2007-07-15

    The thin film growth has been confirmed to be assembled by an enormous number of clusters in experiments of CVD. Sequence of clusters' depositions proceeds to form the thin film at short time as gas fluids through surface of substrate. In order to grow condensed thin film using series of cluster deposition, the effect of initial velocity, substrate temperature and density of clusters on property of deposited thin film, especially appearance of nanoscale pores inside thin film must be investigated. In this simulation, three different cluster sizes of 203, 653, 1563 atoms with different velocities (0, 10, 100, 1000 and 3000 m/s) were deposited on a Cu(0 0 1) substrate whose temperatures were set between 300 and 1000 K. Four clusters and one cluster were used in primary deposition and secondary deposition, respectively. We have clarified that adhesion between clusters and substrate is greatly influenced by initial velocity. As a result, the exfoliation pattern of deposited thin film is dependent on initial velocity and different between them. One borderline dividing whole region into porous region and nonporous region are obtained to show the effect of growth conditions on appearance of nanoscale pores inside thin film. Moreover, we have also shown that the likelihood of porous thin film is dependent on the point of impact of a cluster relative to previously deposited clusters.

  15. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    Jayakumar, S.; Kannan, M.D.; Prasanna, S.

    2012-01-01

    The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

  16. A photochemical approach designed to improve the coating of nanoscale silver films onto food plastic wrappings intended to control bacterial hazards

    International Nuclear Information System (INIS)

    Mustatea, Gabriel; Vidal, Loïc; Calinescu, Ioan; Dobre, Alina; Ionescu, Mariana; Balan, Lavinia

    2015-01-01

    Plasmonic silver film was directly generated on a variety of substrates through a facile and environmentally friendly method, which involves a UV-photoreduction process without any reducing or stabilizing agent and requiring no thermal step. Top-coated films of unprotected silver nanoparticles (3–11 nm) were generated from hydroalcoholic AgNO 3 solution and directly on glass substrates or food packaging plastic wraps, low density polyethylene film, and polyvinyl chloride. The natural antibacterial activity of the material was evaluated. The correlation between silver migration and antimicrobial activity of silver-functionalized substrates against pure strains of gram-negative bacteria (Escherichia coli) and gram-positive bacteria (Staphylococcus aureus) was demonstrated. By way of illustration, food plastic wraps top-coated in this way exhibited a high antibacterial activity. The metal nanoparticle film obtained in this way was characterized and the influence of several parameters (fluence, exposure, silver nitrate concentration, and nature of the free radicals generator) on their formation was studied. Moreover, by shaping the actinic beam with an appropriate device, it is very easy to pattern the brown yellow silver nanofilm or to print messages in plain text

  17. A photochemical approach designed to improve the coating of nanoscale silver films onto food plastic wrappings intended to control bacterial hazards

    Energy Technology Data Exchange (ETDEWEB)

    Mustatea, Gabriel [University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science (Romania); Vidal, Loïc [Institut de Sciences des Matériaux de Mulhouse, CNRS UMR 7361 (France); Calinescu, Ioan [University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science (Romania); Dobre, Alina; Ionescu, Mariana [National Research and Development Institute for Food Bioresources – IBA Bucharest (Romania); Balan, Lavinia, E-mail: lavinia.balan@uha.fr [Institut de Sciences des Matériaux de Mulhouse, CNRS UMR 7361 (France)

    2015-01-15

    Plasmonic silver film was directly generated on a variety of substrates through a facile and environmentally friendly method, which involves a UV-photoreduction process without any reducing or stabilizing agent and requiring no thermal step. Top-coated films of unprotected silver nanoparticles (3–11 nm) were generated from hydroalcoholic AgNO{sub 3} solution and directly on glass substrates or food packaging plastic wraps, low density polyethylene film, and polyvinyl chloride. The natural antibacterial activity of the material was evaluated. The correlation between silver migration and antimicrobial activity of silver-functionalized substrates against pure strains of gram-negative bacteria (Escherichia coli) and gram-positive bacteria (Staphylococcus aureus) was demonstrated. By way of illustration, food plastic wraps top-coated in this way exhibited a high antibacterial activity. The metal nanoparticle film obtained in this way was characterized and the influence of several parameters (fluence, exposure, silver nitrate concentration, and nature of the free radicals generator) on their formation was studied. Moreover, by shaping the actinic beam with an appropriate device, it is very easy to pattern the brown yellow silver nanofilm or to print messages in plain text.

  18. A photochemical approach designed to improve the coating of nanoscale silver films onto food plastic wrappings intended to control bacterial hazards

    Science.gov (United States)

    Mustatea, Gabriel; Vidal, Loïc; Calinescu, Ioan; Dobre, Alina; Ionescu, Mariana; Balan, Lavinia

    2015-01-01

    Plasmonic silver film was directly generated on a variety of substrates through a facile and environmentally friendly method, which involves a UV-photoreduction process without any reducing or stabilizing agent and requiring no thermal step. Top-coated films of unprotected silver nanoparticles (3-11 nm) were generated from hydroalcoholic AgNO3 solution and directly on glass substrates or food packaging plastic wraps, low density polyethylene film, and polyvinyl chloride. The natural antibacterial activity of the material was evaluated. The correlation between silver migration and antimicrobial activity of silver-functionalized substrates against pure strains of gram-negative bacteria ( Escherichia coli) and gram-positive bacteria ( Staphylococcus aureus) was demonstrated. By way of illustration, food plastic wraps top-coated in this way exhibited a high antibacterial activity. The metal nanoparticle film obtained in this way was characterized and the influence of several parameters (fluence, exposure, silver nitrate concentration, and nature of the free radicals generator) on their formation was studied. Moreover, by shaping the actinic beam with an appropriate device, it is very easy to pattern the brown yellow silver nanofilm or to print messages in plain text.

  19. The biological properties of the silver- and copper-doped ceramic biomaterial

    International Nuclear Information System (INIS)

    Lysenko, Oleksandr; Dubok, Oleksii; Borysenko, Anatolii; Shinkaruk, Oleksandr

    2015-01-01

    The biological properties of nanostructured bioactive ceramic composite (BCC) granules doped with 0.1–10 at.% silver and 0.05–5 at.% copper have been investigated both in vitro and in vivo to develop effective alloplastic material for infected bone defect substitute. It is assumed that the granules consisting of biphasic calcium phosphate and bioactive glass ceramics due to their nanoscale (15–40 nm) and multiphase structure, bioelement placement in different ceramic phases as well as antimicrobial effect should improve osteogenic properties and biocompatibility. Tests in vitro have been conducted with multipotent mesenchymal stromal cells (MSCs) and test strains of microorganisms. The same biocomposite has been used in vivo to study the repair of bone defects in animal model. The findings indicate that doped BCC leads to antimicrobial activity. Inhibition of MSCs growth has been observed for granules doped with ions of more than 1 at.% silver and 0.5 at.% copper. The results of the in vivo study reveal that BCC implantation significantly improves bone reparation. Differences between bone repair with undoped and doped, with 1 at.% silver and 0.5 at.% copper, ceramic samples were not observed. The BCC doped within 0.5–1 at.% silver and 0.25–0.5 at.% copper stimulates bone tissue repair and has satisfactory biocompatibility and antimicrobial properties

  20. The biological properties of the silver- and copper-doped ceramic biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Lysenko, Oleksandr, E-mail: dr.alex.lysenko@gmail.com [Bogomolets National Medical University, Department of Therapeutic Stomatology (Ukraine); Dubok, Oleksii [Institute for Problems of Material Science NASU, Department of Analytical Chemistry and Functional Ceramics (Ukraine); Borysenko, Anatolii [Bogomolets National Medical University, Department of Therapeutic Stomatology (Ukraine); Shinkaruk, Oleksandr [Institute for Problems of Material Science NASU, Department of Analytical Chemistry and Functional Ceramics (Ukraine)

    2015-04-15

    The biological properties of nanostructured bioactive ceramic composite (BCC) granules doped with 0.1–10 at.% silver and 0.05–5 at.% copper have been investigated both in vitro and in vivo to develop effective alloplastic material for infected bone defect substitute. It is assumed that the granules consisting of biphasic calcium phosphate and bioactive glass ceramics due to their nanoscale (15–40 nm) and multiphase structure, bioelement placement in different ceramic phases as well as antimicrobial effect should improve osteogenic properties and biocompatibility. Tests in vitro have been conducted with multipotent mesenchymal stromal cells (MSCs) and test strains of microorganisms. The same biocomposite has been used in vivo to study the repair of bone defects in animal model. The findings indicate that doped BCC leads to antimicrobial activity. Inhibition of MSCs growth has been observed for granules doped with ions of more than 1 at.% silver and 0.5 at.% copper. The results of the in vivo study reveal that BCC implantation significantly improves bone reparation. Differences between bone repair with undoped and doped, with 1 at.% silver and 0.5 at.% copper, ceramic samples were not observed. The BCC doped within 0.5–1 at.% silver and 0.25–0.5 at.% copper stimulates bone tissue repair and has satisfactory biocompatibility and antimicrobial properties.

  1. Silver-Doping Effects and Photostructural Transformation in Evaporated AS2S3 Thin Films.

    Science.gov (United States)

    1982-02-16

    of evaporated silver halide films. The details of the preparation of evaporated films of silver halides are reported by Junod at. al. (41 ) The...1980). 40. M.S. Chang, N.D. Hwang, J.T. Chen, Extended Abstr. Electrochem. Soc., 80-1, 692, (1980). 41. P. Junod , N. MHediger, B. Kilchoy. R. Steiger

  2. Radiative decay of surface plasmons on nonspherical silver particles

    International Nuclear Information System (INIS)

    Little, J.W.; Ferrell, T.L.; Callcott, T.A.; Arakawa, E.T.

    1982-01-01

    We have studied the radiation emitted by electron-bombarded silver particles. Electron micrographs have shown that the particles, obtained by heating thin (5 nm) silver films, were oblate (flattened) with minor axes aligned along the substrate normal. The characteristic wavelength obtained by bombarding these particles with 15-keV electrons was found to vary with angle of photon emission. We have modeled this wavelength shift as a result of the mixture of radiation from dipole and quadrupole surface-plasmon oscillations on oblate spheroids. Experimental observations of the energy, polarization, and angular distribution of the emitted radiation are in good agreement with theoretical calculations

  3. One-pot Synthesis of Soluble Nanoscale CIGS Photoactive Functional Materials

    Directory of Open Access Journals (Sweden)

    Yan Aixia

    2007-01-01

    Full Text Available Abstract Promising alternatives for solar energy utilization are thin film technologies involving various new materials. This contribution describes an easy and inexpensive synthetic method that can be used to prepare soluble nanoscale triphenyl phosphine-coordinated CIGS (TPP-CIGS photoactive functional materials. This complex is stable in the solid state under the irradiation of the ambient light, but its solution becomes a little bit unstable under the illumination of the low intensity laser.

  4. Field emission studies of silver nanoparticles synthesized by electron cyclotron resonance plasma

    International Nuclear Information System (INIS)

    Purohit, Vishwas; Mazumder, Baishakhi; Bhise, A.B.; Poddar, Pankaj; Joag, D.S.; Bhoraskar, S.V.

    2011-01-01

    Field emission has been studied for silver nanoparticles (25-200 nm), deposited within a cylindrical silver target in an electron cyclotron resonance (ECR) plasma. Particle size distribution was controlled by optimum biasing voltages between the chamber and the target. Presence of non-oxidized silver was confirmed from the X-Ray diffraction analysis; however, thin protective layer of oxide was identified from the selective area electron diffraction pattern obtained with transmission electron microscopy. The silver nanoparticles were seen to exhibit hilly pointed like structures when viewed under the atomic force microscopy (AFM). The emissive properties of these particles were investigated by field emission microscopy. It is found that this technique of deposition is ideal for formation of nanoparticles films on different substrate geometries with size controllability as well as its application to emission devices.

  5. Superhydrophobic Ag decorated ZnO nanostructured thin film as effective surface enhanced Raman scattering substrates

    Science.gov (United States)

    Jayram, Naidu Dhanpal; Sonia, S.; Poongodi, S.; Kumar, P. Suresh; Masuda, Yoshitake; Mangalaraj, D.; Ponpandian, N.; Viswanathan, C.

    2015-11-01

    The present work is an attempt to overcome the challenges in the fabrication of super hydrophobic silver decorated zinc oxide (ZnO) nanostructure thin films via thermal evaporation process. The ZnO nanowire thin films are prepared without any surface modification and show super hydrophobic nature with a contact angle of 163°. Silver is further deposited onto the ZnO nanowire to obtain nanoworm morphology. Silver decorated ZnO (Ag@ZnO) thin films are used as substrates for surface enhanced Raman spectroscopy (SERS) studies. The formation of randomly arranged nanowire and silver decorated nanoworm structure is confirmed using FESEM, HR-TEM and AFM analysis. Crystallinity and existence of Ag on ZnO are confirmed using XRD and XPS studies. A detailed growth mechanism is discussed for the formation of the nanowires from nanobeads based on various deposition times. The prepared SERS substrate reveals a reproducible enhancement of 3.082 × 107 M for Rhodamine 6G dye (R6G) for 10-10 molar concentration per liter. A higher order of SERS spectra is obtained for a contact angle of 155°. Thus the obtained thin films show the superhydrophobic nature with a highly enhanced Raman spectrum and act as SERS substrates. The present nanoworm morphology shows a new pathway for the construction of semiconductor thin films for plasmonic studies and challenges the orderly arranged ZnO nanorods, wires and other nano structure substrates used in SERS studies.

  6. Preparation of Crosslinked Amphiphilic Silver Nanogel as Thin Film Corrosion Protective Layer for Steel

    Directory of Open Access Journals (Sweden)

    Ayman M. Atta

    2014-07-01

    Full Text Available Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA and potassium peroxydisulfate (KPS were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR, transmission and scanning electron microscopy (TEM and SEM. The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.

  7. Thickness- and Particle-Size-Dependent Electrochemical Reduction of Carbon Dioxide on Thin-Layer Porous Silver Electrodes.

    Science.gov (United States)

    Zhang, Lin; Wang, Zhiyong; Mehio, Nada; Jin, Xianbo; Dai, Sheng

    2016-03-08

    The electrochemical reduction of CO2 can not only convert it back into fuels, but is also an efficient manner to store forms of renewable energy. Catalysis with silver is a possible technology for CO2 reduction. We report that in the case of monolithic porous silver, the film thickness and primary particle size of the silver particles, which can be controlled by electrochemical growth/reduction of AgCl film on silver substrate, have a strong influence on the electrocatalytic activity towards CO2 reduction. A 6 μm thick silver film with particle sizes of 30-50 nm delivers a CO formation current of 10.5 mA cm(-2) and a mass activity of 4.38 A gAg (-1) at an overpotential of 0.39 V, comparable to levels achieved with state-of-the-art gold catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Angle-sensitive and fast photovoltage of silver nanocluster embeded ZnO thin films induced by 1.064-μm pulsed laser

    International Nuclear Information System (INIS)

    Song-Qing, Zhao; Li-Min, Yang; Wen-Wei, Liu; Kun, Zhao; Yue-Liang, Zhou; Qing-Li, Zhou

    2010-01-01

    Silver nanocluster embedded ZnO composite thin film was observed to have an angle-sensitive and fast photovoltaic effect in the angle range from −90° to 90°, its peak value and the polarity varied regularly with the angle of incidence of the 1.064-μm pulsed Nd:YAG laser radiation onto the ZnO surface. Meanwhile, for each photovoltaic signal, its rising time reached ∼2 ns with an open-circuit photovoltage of ∼2 ns full width at half-maximum. This angle-sensitive fast photovoltaic effect is expected to put this composite film a candidate for angle-sensitive and fast photodetector. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  9. Nanoscale thermal transport. II. 2003-2012

    Science.gov (United States)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ˜ 1 nm , the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and thermal

  10. Microscopic local fatigue in PZT thin films

    International Nuclear Information System (INIS)

    Li, B S; Wu, A; Vilarinho, P M

    2007-01-01

    The reduction in switchable polarization during fatigue largely limits the application of PZT thin films in ferroelectric nonvolatile memories. So, it is very important to understand the fatigue mechanism in PZT films, especially at a nanoscale level. In this paper, nanoscale fatigue properties in PZT thin films have been studied by piezoresponse force microscopy and local piezoloops. It has been found that a piezoloop obtained on a fatigued point exhibits a much more pinched shape and a local imprint phenomenon is observed after severe fatigue. Furthermore, the domain structure evolves from a simple single-peak profile to a complex fluctuant one. However, there is only some shift of the piezoloop when a unipolar field with the same amplitude is applied on the film. The available experimental data show that there exist obvious domain wall pinning and injection of electrons into the film during fatigue. Finally, a schematic illustration is suggested to explain the possible fatigue mechanism

  11. Nanogap embedded silver gratings for surface plasmon enhanced fluorescence

    Science.gov (United States)

    Bhatnagar, Kunal

    Plasmonic nanostructures have been extensively used in the past few decades for applications in sub-wavelength optics, data storage, optoelectronic circuits, microscopy and bio-photonics. The enhanced electromagnetic field produced at the metal and dielectric interface by the excitation of surface plasmons via incident radiation can be used for signal enhancement in fluorescence and surface enhanced Raman scattering studies. Novel plasmonic structures have shown to provide very efficient and extreme light concentration at the nano-scale in recent years. The enhanced electric field produced within a few hundred nanometers of these surfaces can be used to excite fluorophores in the surrounding environment. Fluorescence based bio-detection and bio-imaging are two of the most important tools in the life sciences and improving the qualities and capabilities of fluorescence based detectors and imaging equipment remains a big challenge for industry manufacturers. We report a novel fabrication technique for producing nano-gap embedded periodic grating substrates on the nanoscale using a store bought HD-DVD and conventional soft lithography procedures. Polymethylsilsesquioxane (PMSSQ) polymer is used as the ink for the micro-contact printing process with PDMS stamps obtained from the inexpensive HD-DVDs as master molds. Fluorescence enhancement factors of up to 118 times were observed with these silver nanostructures in conjugation with Rhodamine-590 fluorescent dye. These substrates are ideal candidates for a robust and inexpensive optical system with applications such as low-level fluorescence based analyte detection, single molecule imaging, and surface enhanced Raman studies. Preliminary results in single molecule experiments have also been obtained by imaging individual 3 nm and 20 nm dye-doped nanoparticles attached to the silver plasmonic gratings using epi-fluorescence microscopy.

  12. DNA-Protected Silver Clusters for Nanophotonics

    Directory of Open Access Journals (Sweden)

    Elisabeth Gwinn

    2015-02-01

    Full Text Available DNA-protected silver clusters (AgN-DNA possess unique fluorescence properties that depend on the specific DNA template that stabilizes the cluster. They exhibit peak emission wavelengths that range across the visible and near-IR spectrum. This wide color palette, combined with low toxicity, high fluorescence quantum yields of some clusters, low synthesis costs, small cluster sizes and compatibility with DNA are enabling many applications that employ AgN-DNA. Here we review what is known about the underlying composition and structure of AgN-DNA, and how these relate to the optical properties of these fascinating, hybrid biomolecule-metal cluster nanomaterials. We place AgN-DNA in the general context of ligand-stabilized metal clusters and compare their properties to those of other noble metal clusters stabilized by small molecule ligands. The methods used to isolate pure AgN-DNA for analysis of composition and for studies of solution and single-emitter optical properties are discussed. We give a brief overview of structurally sensitive chiroptical studies, both theoretical and experimental, and review experiments on bringing silver clusters of distinct size and color into nanoscale DNA assemblies. Progress towards using DNA scaffolds to assemble multi-cluster arrays is also reviewed.

  13. Effect of silver nanoparticles on human mesenchymal stem cell differentiation

    Directory of Open Access Journals (Sweden)

    Christina Sengstock

    2014-11-01

    Full Text Available Background: Silver nanoparticles (Ag-NP are one of the fastest growing products in nano-medicine due to their enhanced antibacterial activity at the nanoscale level. In biomedicine, hundreds of products have been coated with Ag-NP. For example, various medical devices include silver, such as surgical instruments, bone implants and wound dressings. After the degradation of these materials, or depending on the coating technique, silver in nanoparticle or ion form can be released and may come into close contact with tissues and cells. Despite incorporation of Ag-NP as an antibacterial agent in different products, the toxicological and biological effects of silver in the human body after long-term and low-concentration exposure are not well understood. In the current study, we investigated the effects of both ionic and nanoparticulate silver on the differentiation of human mesenchymal stem cells (hMSCs into adipogenic, osteogenic and chondrogenic lineages and on the secretion of the respective differentiation markers adiponectin, osteocalcin and aggrecan.Results: As shown through laser scanning microscopy, Ag-NP with a size of 80 nm (hydrodynamic diameter were taken up into hMSCs as nanoparticulate material. After 24 h of incubation, these Ag-NP were mainly found in the endo-lysosomal cell compartment as agglomerated material. Cytotoxicity was observed for differentiated or undifferentiated hMSCs treated with high silver concentrations (≥20 µg·mL−1 Ag-NP; ≥1.5 µg·mL−1 Ag+ ions but not with low-concentration treatments (≤10 µg·mL−1 Ag-NP; ≤1.0 µg·mL−1 Ag+ ions. Subtoxic concentrations of Ag-NP and Ag+ ions impaired the adipogenic and osteogenic differentiation of hMSCs in a concentration-dependent manner, whereas chondrogenic differentiation was unaffected after 21 d of incubation. In contrast to aggrecan, the inhibitory effect of adipogenic and osteogenic differentiation was confirmed by a decrease in the secretion of

  14. Silver nanoparticles: synthesis and size control by electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bogle, K A; Dhole, S D; Bhoraskar, V N [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

    2006-07-14

    Silver nanoparticles were synthesized by irradiating solutions, prepared by mixing AgNO{sub 3} and poly-vinyl alcohol (PVA), with 6 MeV electrons. The electron-irradiated solutions and the thin coatings cast from them were characterized using the ultraviolet-visible (UV-vis), x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. During electron irradiation, the process of formation of the silver nanoparticles appeared to be initiated at an electron fluence of {approx}2 x 10{sup 13} e cm{sup -2}. This was evidenced from the solution, which turned yellow and exhibited the characteristic plasmon absorption peak around 455 nm. Silver nanoparticles of different sizes in the range 60-10 nm, with a narrow size distribution, could be synthesized by varying the electron fluence from 2 x 10{sup 13} to 3 x 10{sup 15} e cm{sup -2}. Silver nanoparticles of sizes in the range 100-200 nm were also synthesized by irradiating an aqueous AgNO{sub 3} solution with 6 MeV electrons.

  15. Self-limiting atomic layer deposition of conformal nanostructured silver films

    International Nuclear Information System (INIS)

    Golrokhi, Zahra; Chalker, Sophia; Sutcliffe, Christopher J.; Potter, Richard J.

    2016-01-01

    Graphical abstract: - Highlights: • We grow metallic silver by direct liquid injection thermal atomic layer deposition. • Highly conformal silver nanoparticle coatings on high aspect ratio surfaces. • An ALD temperature growth window between 123 and 128 °C is established. • ALD cycles provides sub nanometre control of silver growth. • Catalytic dehydrogenation ALD mechanism has been elucidated by in-situ QCM. - Abstract: The controlled deposition of ultra-thin conformal silver nanoparticle films is of interest for applications including anti-microbial surfaces, plasmonics, catalysts and sensors. While numerous techniques can produce silver nanoparticles, few are able to produce highly conformal coatings on high aspect ratio surfaces, together with sub-nanometre control and scalability. Here we develop a self-limiting atomic layer deposition (ALD) process for the deposition of conformal metallic silver nanoparticle films. The films have been deposited using direct liquid injection ALD with ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) and propan-1-ol. An ALD temperature window between 123 and 128 °C is identified and within this range self-limiting growth is confirmed with a mass deposition rate of ∼17.5 ng/cm"2/cycle. The effects of temperature, precursor dose, co-reactant dose and cycle number on the deposition rate and on the properties of the films have been systematically investigated. Under self-limiting conditions, films are metallic silver with a nano-textured surface topography and nanoparticle size is dependent on the number of ALD cycles. The ALD reaction mechanisms have been elucidated using in-situ quartz crystal microbalance (QCM) measurements, showing chemisorption of the silver precursor, followed by heterogeneous catalytic dehydrogenation of the alcohol to form metallic silver and an aldehyde.

  16. The Morphology of Silver Layers on SU8 polymers prepared by Electroless Deposition

    Science.gov (United States)

    Dutta, Aniruddha; Yuan, Biao; Heinrich, Helge; Grabill, Chris; Williams, Henry; Kuebler, Stephen; Bhattacharya, Aniket

    2010-03-01

    Silver was deposited onto the functionalized surface of polymeric SU-8 where gold nanoparticles (Au-NPs) act as nucleation sites using electroless metallization chemistry. Here we report on the evolution of the nanoscale morphology of deposited Ag studied by Transmission Electron Microscopy (TEM). In TEM of sample cross sections correlations between the original gold and the silver nanoparticles were obtained while plan-view TEM results showed the distribution of nanoparticles on the surface. Scanning TEM with a high-angle annular dark field detector was used to obtain atomic number contrast. The morphology of the deposited Ag was controlled through the presence and absence of gum Arabic. The thickness and height fluctuations of the Ag layer were determined as a function of time and a statistical analysis of the growth process was conducted for the initial deposition periods.

  17. Pulsed laser deposition of antimicrobial silver coating on Ormocer (registered) microneedles

    Energy Technology Data Exchange (ETDEWEB)

    Gittard, S D; Narayan, R J; Jin, C; Monteiro-Riviere, N A [Joint Department of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Ovsianikov, A; Chichkov, B N [Laser Zentrum Hannover, Hollerithallee 8, 30419 Hannover (Germany); Stafslien, S; Chisholm, B, E-mail: roger_narayan@msn.co [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States)

    2009-12-15

    One promising option for transdermal delivery of protein- and nucleic acid-based pharmacologic agents involves the use of microneedles. However, microneedle-generated pores may allow microorganisms to penetrate the stratum corneum layer of the epidermis and cause local or systemic infection. In this study, microneedles with antimicrobial functionality were fabricated using two-photon polymerization-micromolding and pulsed laser deposition. The antibacterial activity of the silver-coated organically modified ceramic (Ormocer (registered) ) microneedles was demonstrated using an agar diffusion assay. Human epidermal keratinocyte viability on the Ormocer (registered) surfaces coated with silver was similar to that on uncoated Ormocer (registered) surfaces. This study indicates that coating microneedles with silver thin films using pulsed laser deposition is a useful and novel approach for creating microneedles with antimicrobial functionality. (communication)

  18. Pulsed laser deposition of antimicrobial silver coating on Ormocer (registered) microneedles

    International Nuclear Information System (INIS)

    Gittard, S D; Narayan, R J; Jin, C; Monteiro-Riviere, N A; Ovsianikov, A; Chichkov, B N; Stafslien, S; Chisholm, B

    2009-01-01

    One promising option for transdermal delivery of protein- and nucleic acid-based pharmacologic agents involves the use of microneedles. However, microneedle-generated pores may allow microorganisms to penetrate the stratum corneum layer of the epidermis and cause local or systemic infection. In this study, microneedles with antimicrobial functionality were fabricated using two-photon polymerization-micromolding and pulsed laser deposition. The antibacterial activity of the silver-coated organically modified ceramic (Ormocer (registered) ) microneedles was demonstrated using an agar diffusion assay. Human epidermal keratinocyte viability on the Ormocer (registered) surfaces coated with silver was similar to that on uncoated Ormocer (registered) surfaces. This study indicates that coating microneedles with silver thin films using pulsed laser deposition is a useful and novel approach for creating microneedles with antimicrobial functionality. (communication)

  19. Direct nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation.

    Science.gov (United States)

    El Mel, Abdel-Aziz; Stephant, Nicolas; Gautier, Romain

    2016-10-06

    In this communication, we report on the growth, direct writing and nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation using a scanning electron microscope. The nanoblocks are produced by placing a droplet of an ethylene glycol solution containing silver nitrate and polyvinylpyrrolidone diluted in ethanol directly on a hot substrate heated up to 150 °C. Upon complete evaporation of the droplet, nanospheres, nano- and micro-triangles and nanoblocks made of silver-containing polymers, form over the substrate surface. Considering the nanoblocks as a model system, we demonstrate that such nanostructures are extremely sensitive to the e-beam extracted from the source of a scanning electron microscope operating at low acceleration voltages (between 5 and 7 kV). This sensitivity allows us to efficiently create various nanopatterns (e.g. arrays of holes, oblique slits and nanotrenches) in the material under e-beam irradiation. In addition to the possibility of writing, the nanoblocks revealed a self-healing ability allowing them to recover a relatively smooth surface after etching. Thanks to these properties, such nanomaterials can be used as a support for data writing and erasing on the nanoscale under low energy electron beam irradiation.

  20. Effects of particle size and coating on nanoscale Ag and TiO₂ exposure in zebrafish (Danio rerio) embryos.

    Science.gov (United States)

    Osborne, Olivia J; Johnston, Blair D; Moger, Julian; Balousha, Mohammed; Lead, Jamie R; Kudoh, Tetsuhiro; Tyler, Charles R

    2013-12-01

    Manufactured metal (oxide) nanoparticles are entering the aquatic environment with little understanding on their potential health impacts for exposed organisms. Adopting an integrative approach, we investigated effects of particle size and coating on biological responses for two of the most commonly used metal (oxide) nanoscale particles, silver (Ag) and titanium dioxide (TiO₂) in zebrafish embryos. Titanium dioxide nanoparticles (nominally, 4 nm, 10 nm, 30 nm and 134 nm) had little or no toxicity on the endpoints measured. Ag both in nano form (10 nm and 35 nm) and its larger counterpart (600-1600 nm) induced dose-dependent lethality and morphological defects, occurring predominantly during gastrula stage. Of the silver material tested 10 nm nanoparticles appeared to be the most toxic. Coating Ag nanoparticles with citrate or fulvic acid decreased toxicity significantly. In situ hybridisation analysis identified the yolk syncytial layer (YSL) as a target tissue for Ag-nano toxicity where there was a significant induction of the heavy metal stress response gene, metallothionein 2 (Mt2) at sub-lethal exposures. Coherent Anti-stroke Raman Scattering (CARS) microscopy provided no evidence for silver particles crossing the chorionic membrane in exposed embryos. Collectively, our data suggest that silver ions play a major role in the toxicity of Ag nanoparticles.

  1. Oxygen content modulation by nanoscale chemical and electrical patterning in epitaxial SrCoO3-δ (0 < δ ≤ 0.5) thin films.

    Science.gov (United States)

    Hu, S; Seidel, J

    2016-08-12

    Fast controllable redox reactions in solid materials at room temperature are a promising strategy for enhancing the overall performance and lifetime of many energy technology materials and devices. Easy control of oxygen content is a key concept for the realisation of fast catalysis and bulk diffusion at room temperature. Here, high quality epitaxial brownmillerite SrCoO2.5 thin films have been oxidised to perovskite (P) SrCoO3 with NaClO. X-ray diffraction, scanning probe microscopy and x-ray photoelectron spectroscopy measurements were performed to investigate the structural and electronic changes of the material. The oxidised thin films were found to exhibit distinct morphological changes from an atomically flat terrace structure to forming small nanosized islands with boundaries preferentially in [100] or [010] directions all over the surface, relaxing the in-plane strain imposed by the substrate. The conductivity, or oxygen content, of each single island is confined by these textures, which can be locally patterned even further with electric poling. The high charging level at the island boundaries indicates a magnified electric capacity of SCO thin films, which could be exploited in future device geometries. This finding represents a new way of oxygen modulation with associated self-assembled charge confinement to nanoscale boundaries, offering interesting prospects in nanotechnology applications.

  2. Optimization of silver-dielectric-silver nanoshell for sensing applications

    International Nuclear Information System (INIS)

    Shirzaditabar, Farzad; Saliminasab, Maryam

    2013-01-01

    In this paper, resonance light scattering (RLS) properties of a silver-dielectric-silver nanoshell, based on quasi-static approach and plasmon hybridization theory, are investigated. Scattering spectrum of silver-dielectric-silver nanoshell has two intense and clearly separated RLS peaks and provides a potential for biosensing based on surface plasmon resonance and surface-enhanced Raman scattering. The two RLS peaks in silver-dielectric-silver nanoshell are optimized by tuning the geometrical dimensions. In addition, the optimal geometry is discussed to obtain the high sensitivity of silver-dielectric-silver nanoshell. As the silver core radius increases, the sensitivity of silver-dielectric-silver nanoshell decreases whereas increasing the middle dielectric thickness increases the sensitivity of silver-dielectric-silver nanoshell

  3. Reduced contact resistance of a-IGZO thin film transistors with inkjet-printed silver electrodes

    Science.gov (United States)

    Chen, Jianqiu; Ning, Honglong; Fang, Zhiqiang; Tao, Ruiqiang; Yang, Caigui; Zhou, Yicong; Yao, Rihui; Xu, Miao; Wang, Lei; Peng, Junbiao

    2018-04-01

    In this study, high performance amorphous In–Ga–Zn–O (a-IGZO) TFTs were successfully fabricated with inkjet-printed silver source-drain electrodes. The results showed that increased channel thickness has an improving trend in the properties of TFTs due to the decreased contact resistance. Compared with sputtered silver TFTs, devices with printed silver electrodes were more sensitive to the thickness of active layer. Furthermore, the devices with optimized active layer showed high performances with a maximum saturation mobility of 8.73 cm2 · V‑1 · S‑1 and an average saturation mobility of 6.97 cm2 · V‑1 · S‑1, I on/I off ratio more than 107 and subthreshold swing of 0.28 V/decade, which were comparable with the analogous devices with sputtered electrodes.

  4. Microwave flash sintering of inkjet-printed silver tracks on polymer substrates

    NARCIS (Netherlands)

    Perelaer, J.; Klokkenburg, M.; Hendriks, C.E.; Schubert, U.S.

    2009-01-01

    Microwave flash sintering of inkjet printed colloidal silver dispersions on thin polymer substrates was studied as a function of the antenna area and initial resistance. The presence of conductive antennae promotes nanoparticle sintering in predried ink lines. For dried nanoparticle inks connected

  5. Antibacterial surfaces by adsorptive binding of polyvinyl-sulphonate-stabilized silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vasilev, Krasimir; Sah, Vasu R; Goreham, Renee V; Short, Robert D [Mawson Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, Adelaide, SA 5095 (Australia); Ndi, Chi; Griesser, Hans J, E-mail: Krasimir.vasilev@unisa.edu.au [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)

    2010-05-28

    This paper presents a novel and facile method for the generation of efficient antibacterial coatings which can be applied to practically any type of substrate. Silver nanoparticles were stabilized with an adsorbed surface layer of polyvinyl sulphonate (PVS). This steric layer provided excellent colloidal stability, preventing aggregation over periods of months. PVS-coated silver nanoparticles were bound onto amine-containing surfaces, here produced by deposition of an allylamine plasma polymer thin film onto various substrates. SEM imaging showed no aggregation upon surface binding of the nanoparticles; they were well dispersed on amine surfaces. Such nanoparticle-coated surfaces were found to be effective in preventing attachment of Staphylococcus epidermidis bacteria and also in preventing biofilm formation. Combined with the ability of plasma polymerization to apply the thin polymeric binding layer onto a wide range of materials, this method appears promising for the fabrication of a wide range of infection-resistant biomedical devices.

  6. Strategies for specifically directing metal functionalization of protein nanotubes: constructing protein coated silver nanowires

    International Nuclear Information System (INIS)

    Carreño-Fuentes, Liliana; Palomares, Laura A; Ramírez, Octavio T; Ascencio, Jorge A; Medina, Ariosto; Aguila, Sergio

    2013-01-01

    Biological molecules that self-assemble in the nanoscale range are useful multifunctional materials. Rotavirus VP6 protein self-assembles into tubular structures in the absence of other rotavirus proteins. Here, we present strategies for selectively directing metal functionalization to the lumen of VP6 nanotubes. The specific in situ metal reduction in the inner surface of nanotube walls was achieved by the simple modification of a method previously reported to functionalize the nanotube outer surface. Silver nanorods and nanowires as long as 1.5 μm were formed inside the nanotubes by coalescence of nanoparticles. Such one-dimensional structures were longer than others previously obtained using bioscaffolds. The interactions between silver ions and the nanotube were simulated to understand the conditions that allowed nanowire formation. Molecular docking showed that a naturally occurring arrangement of aspartate residues enabled the stabilization of silver ions on the internal surface of the VP6 nanotubes. This is the first time that such a spatial arrangement has been proposed for the nucleation of silver nanoparticles, opening the possibility of using such an array to direct functionalization of other biomolecules. These results demonstrate the natural capabilities of VP6 nanotubes to function as a versatile biotemplate for nanomaterials. (paper)

  7. The effect of silver thickness on the enhancement of polymer based SERS substrates

    International Nuclear Information System (INIS)

    Schneidewind, H; Weber, K; Zeisberger, M; Hübner, U; Dellith, A; Cialla-May, D; Mattheis, R; Popp, J

    2014-01-01

    We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films. (paper)

  8. A concetration-dependent model for silver colloids in nanostructured sol-gel materials

    Science.gov (United States)

    Garcia-Macedo, Jorge A.; Franco, Alfredo; Renteria, Victor; Valverde-Aguilar, Guadalupe

    2005-08-01

    We report on the physical modelling of the photoconductive response of nanostructured sol-gel films in function of the silver nitrate concentration (ions and colloids). This model considers several factors as the silver nitrate concentration and the transport parameters obtained. The model is compared with others commonly used. 2d-hexagonal nanostructured sol-gel thin films were prepared by dip-coating method using a non-ionic diblock copolymer Brij58 (surfactant) to produce channels into the film. Silver colloids (metallic Ag0 nanoparticles ) were obtained by spontaneous reduction process of Ag+ ions to Ag0. These nanoparticles were deposited into the channels formed by the surfactant. The structure was identified by X-ray diffraction and TEM. An absorption band located at 430 nm was detected by optical absorption; it corresponds to the plasmon surface. Fit to this band with modified Gans theory is presented. Photoconductivity studies were performed on films with silver ions and films with silver colloids to characterized their mechanisms of charge transport in the darkness and under illumination at 420, 633 nm wavelengths. Transport parameters were calculated. The films with silver colloids exhibit a photovoltaic effect stronger than the films with silver ions. While, the last ones possesses a photoconductivity behaviour.

  9. Development of an eco-friendly approach for biogenesis of silver nanoparticles using spores of Bacillus athrophaeus.

    Science.gov (United States)

    Hosseini-Abari, Afrouzossadat; Emtiazi, Giti; Ghasemi, Seyed Mahdi

    2013-12-01

    The biological synthesis methods have been emerging as a promising new approach for production of nanoparticles due to their simplicity and non-toxicity. In the present study, spores of Bacillus athrophaeus were used to achieve the objective of developing a green synthesis method of silver nanoparticles. Enzyme assay revealed that the spores and their heat inactivated forms (microcapsules) were highly active and their enzymatic contents differed from the vegetative cells. Laccase, glucose oxidase, and alkaline phosphatase activities were detected in the dormant forms, but not in the vegetative cells. Although no nanoparticle was produced by active cells of B. athrophaeus, both spores and microcapsules were efficiently capable of reducing the silver ions (Ag⁺) to elemental silver (Ag⁰) leading to the formation of nanoparticles from silver nitrate (AgNO₃). The presence of biologically synthesized silver nanoparticles was determined by obtaining broad spectra with maximum absorbance at 400 nm in UV-visible spectroscopy. The X-ray diffraction analysis pattern revealed that the nanoscale particles have crystalline nature with various topologies, as confirmed by transmission electron microscopy (TEM). The TEM micrograph showed the nanocrystal structures with dimensions ranging from 5 to 30 nm. Accordingly, the spore mixture could be employed as a factory for detoxification of heavy metals and subsequent production of nanoparticles. This research introduces an environmental friendly and cost effective biotechnological process for the extracellular synthesis of silver nanoparticles using the bacterial spores.

  10. Bi-axially crumpled silver thin-film electrodes for dielectric elastomer actuators

    International Nuclear Information System (INIS)

    Low, Sze-Hsien; Lau, Gih-Keong

    2014-01-01

    Metal thin films, which have high conductivity, are much stiffer and may fracture at a much lower strain than dielectric elastomers. In order to fabricate compliant electrodes for use in dielectric elastomer actuators (DEAs), metal thin films have been formed into either zigzag patterns or corrugations, which favour bending and only allow uniaxial DEA deformations. However, biaxially compliant electrodes are desired in order to maximize generated forces of DEA. In this paper, we present crumpled metal thin-film electrodes that are biaxially compliant and have full area coverage over the dielectric elastomer. These crumpled metal thin-film electrodes are more stretchable than flat metal thin films; they remain conductive beyond 110% radial strain. Also, crumpling reduced the stiffening effect of metal thin films on the soft elastomer. As such, DEAs using crumpled metal thin-film electrodes managed to attain relatively high actuated area strains of up to 128% at 1.8 kV (102 Vμm −1 ). (paper)

  11. Silver jewelry of Hellenistic and Celtic type from Hrtkovci in Srem

    Directory of Open Access Journals (Sweden)

    Dautova-Ruševljan Velika

    2006-01-01

    Full Text Available Group find of the silver jewelry of the Hellenistic and Celtic type has been discovered by chance in the area of the Hrtkovci village. The find consists of gilded hinged fibula, three fibulae of the Middle La Tène type and many pendants made of thin silver foil. Most of the finds are dated in the 2nd-1st century BC and only the new type of hinged fibula dates from considerably earlier period, possibly from the end of 4th or the beginning of the 3rd century BC. The new finds of silver jewelry discovered in the area of eastern Srem and dating from the Pre-Roman times confirm the existence of the local workshop connected most probably to the Pre-Roman fortified settlement in Sremska Mitrovica.

  12. Proceedings of the international conference on thin films and applications: book of abstracts

    International Nuclear Information System (INIS)

    2013-01-01

    In the era of miniaturization, the role of thin films is highly significant to achieve smaller devices with higher speed especially in new generation of integrated circuits, sensors, flat panel displays, Micro-Electro-Mechanical Systems (MEMS), biomedical devices, optical instruments and microwave communications. Thin films as a nano-scale dimensional system have great importance to many challenging applications. Biological coatings, clean energy, ferroelectric and piezoelectric thin films, ion beam thin films, magnetic thin films, nanostructured and nano composite coatings, NEMS, sensors, thin film preparation and characterization are the topics covered in this symposium. Papers relevant to INIS are indexed separately

  13. Screen printed silver top electrode for efficient inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Junwoo [Department of Printed Electronics, Korea Institute of Machinery & Materials (KIMM), Daejeon (Korea, Republic of); Duraisamy, Navaneethan [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Lee, Taik-Min [Department of Printed Electronics, Korea Institute of Machinery & Materials (KIMM), Daejeon (Korea, Republic of); Kim, Inyoung, E-mail: ikim@kimm.re.kr [Department of Printed Electronics, Korea Institute of Machinery & Materials (KIMM), Daejeon (Korea, Republic of); Choi, Kyung-Hyun, E-mail: amm@jejunu.ac.kr [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of)

    2015-10-15

    Highlights: • Screen printing of silver pattern. • X-ray diffraction pattern confirmed the face centered cubic structure of silver. • Uniform surface morphology of silver pattern with sheet resistance of 0.06 Ω/sq. • The power conversion efficiency of fabricated solar cell is found to be 2.58%. - Abstract: The present work is mainly focused on replacement of the vacuum process for top electrode fabrication in organic solar cells. Silver top electrode deposited through solution based screen printing on pre-deposited polymeric thin film. The solution based printing technology provides uniform top electrode without damaging the underlying organic layers. The surface crystallinity and surface morphology of silver top electrode are examined through X-ray diffraction, field-emission scanning electron microscope and atomic force microscope. The purity of silver is examined through X-ray energy dispersive spectroscopy. The top electrode exhibits face centered cubic structure with homogeneous morphology. The sheet resistance of top electrode is found to be 0.06 Ω/sq and an average pattern thickness of ∼15 μm. The power conversion efficiency is 2.58%. Our work demonstrates that the solution based screen printing is a significant role in the replacement of vacuum process for the fabrication of top electrode in organic solar cells.

  14. Screen printed silver top electrode for efficient inverted organic solar cells

    International Nuclear Information System (INIS)

    Kim, Junwoo; Duraisamy, Navaneethan; Lee, Taik-Min; Kim, Inyoung; Choi, Kyung-Hyun

    2015-01-01

    Highlights: • Screen printing of silver pattern. • X-ray diffraction pattern confirmed the face centered cubic structure of silver. • Uniform surface morphology of silver pattern with sheet resistance of 0.06 Ω/sq. • The power conversion efficiency of fabricated solar cell is found to be 2.58%. - Abstract: The present work is mainly focused on replacement of the vacuum process for top electrode fabrication in organic solar cells. Silver top electrode deposited through solution based screen printing on pre-deposited polymeric thin film. The solution based printing technology provides uniform top electrode without damaging the underlying organic layers. The surface crystallinity and surface morphology of silver top electrode are examined through X-ray diffraction, field-emission scanning electron microscope and atomic force microscope. The purity of silver is examined through X-ray energy dispersive spectroscopy. The top electrode exhibits face centered cubic structure with homogeneous morphology. The sheet resistance of top electrode is found to be 0.06 Ω/sq and an average pattern thickness of ∼15 μm. The power conversion efficiency is 2.58%. Our work demonstrates that the solution based screen printing is a significant role in the replacement of vacuum process for the fabrication of top electrode in organic solar cells

  15. One-step preparation of antimicrobial silver nanoparticles in polymer matrix

    Energy Technology Data Exchange (ETDEWEB)

    Lyutakov, O., E-mail: lyutakoo@vscht.cz; Kalachyova, Y. [Institute of Chemical Technology, Department of Solid State Engineering (Czech Republic); Solovyev, A. [Institute of Chemical Process Fundamentals of the ASCR (Czech Republic); Vytykacova, S. [Institute of Chemical Technology, Department of Glass and Ceramics (Czech Republic); Svanda, J.; Siegel, J. [Institute of Chemical Technology, Department of Solid State Engineering (Czech Republic); Ulbrich, P. [Institute of Chemical Technology, Department of Biochemistry and Microbiology (Czech Republic); Svorcik, V. [Institute of Chemical Technology, Department of Solid State Engineering (Czech Republic)

    2015-03-15

    Simple one-step procedure for in situ preparation of silver nanoparticles (AgNPs) in the polymer thin films is described. Nanoparticles (NPs) were prepared by reaction of N-methyl pyrrolidone with silver salt in semi-dry polymer film and characterized by transmission electron microscopy, XPS, and UV–Vis spectroscopy techniques. Direct synthesis of NPs in polymer has several advantages; even though it avoids time-consuming NPs mixing with polymer matrix, uniform silver distribution in polymethylmethacrylate (PMMA) films is achieved without necessity of additional stabilization. The influence of the silver concentration, reaction temperature and time on reaction conversion rate, and the size and size-distribution of the AgNPs was investigated. Polymer films doped with AgNPs were tested for their antibacterial activity on Gram-negative bacteria. Antimicrobial properties of AgNPs/PMMA films were found to be depended on NPs concentration, their size and distribution. Proposed one-step synthesis of functional polymer containing AgNPs is environmentally friendly, experimentally simple and extremely quick. It opens up new possibilities in development of antimicrobial coatings with medical and sanitation applications.

  16. One-step preparation of antimicrobial silver nanoparticles in polymer matrix

    International Nuclear Information System (INIS)

    Lyutakov, O.; Kalachyova, Y.; Solovyev, A.; Vytykacova, S.; Svanda, J.; Siegel, J.; Ulbrich, P.; Svorcik, V.

    2015-01-01

    Simple one-step procedure for in situ preparation of silver nanoparticles (AgNPs) in the polymer thin films is described. Nanoparticles (NPs) were prepared by reaction of N-methyl pyrrolidone with silver salt in semi-dry polymer film and characterized by transmission electron microscopy, XPS, and UV–Vis spectroscopy techniques. Direct synthesis of NPs in polymer has several advantages; even though it avoids time-consuming NPs mixing with polymer matrix, uniform silver distribution in polymethylmethacrylate (PMMA) films is achieved without necessity of additional stabilization. The influence of the silver concentration, reaction temperature and time on reaction conversion rate, and the size and size-distribution of the AgNPs was investigated. Polymer films doped with AgNPs were tested for their antibacterial activity on Gram-negative bacteria. Antimicrobial properties of AgNPs/PMMA films were found to be depended on NPs concentration, their size and distribution. Proposed one-step synthesis of functional polymer containing AgNPs is environmentally friendly, experimentally simple and extremely quick. It opens up new possibilities in development of antimicrobial coatings with medical and sanitation applications

  17. Silver nanoparticle–carbon nanotube hybrid films: Preparation and electrochemical sensing

    International Nuclear Information System (INIS)

    Yu Aimin; Wang, Qingxia; Yong, Jiawey; Mahon, Peter J.; Malherbe, Francois; Wang Feng; Zhang Haili; Wang, James

    2012-01-01

    Multi-walled carbon nanotube (MWCNT) multilayer thin films with controlled thickness were pre-assembled on electrodes by alternatively depositing MWCNT and poly(diallyldimethylammonium chloride) (PDDA) via a layer-by-layer self-assembly technique. Silver nanoparticles (Ag NPs) were then electro-deposited on the MWCNT surface from AgNO 3 solution using a potentiostatic double pulse technique. The size, density and morphology of silver nanoparticles that electrodeposited on MWCNT were controlled by the pulse parameters. When a voltage pulse of −600 mV was used to nucleate silver nanoparticles and a growth pulse of −105 mV was applied to grow the particles, silver particles of 10–500 nm with varied density could be electro-generated on MWCNT surface. The formation of Ag NPs and the morphology of the MWCNT/Ag NP composite films were characterized by scanning electron microscopy (SEM). The MWCNT/Ag NP composite films exhibited excellent electrocatalytic activity to the reduction of hydrogen peroxide which was also shown to be slightly affected by the size and density of Ag NPs on the film.

  18. Nanoscale thermal transport. II. 2003–2012

    International Nuclear Information System (INIS)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-01-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ∼1 nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and

  19. Thin-film antifuses for pellistor type gas sensors

    NARCIS (Netherlands)

    Kovalgin, Alexeij Y.; Holleman, J.; van den Berg, Albert; Wallinga, Hans

    2001-01-01

    This work extends our previously reported idea of using the nano-scale conductive link (antifuse) as a combined heating /detecting element in a Pellistor-type gas sensor. Our new thin-film antifuse is designed in such a way that the oxide, for minimising the bulk influence on surface temperature,

  20. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    DEFF Research Database (Denmark)

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back...

  1. Dynamics of silver elution from functionalised antimicrobial nanofiltration membranes.

    Science.gov (United States)

    Choudhari, S; Habimana, O; Hannon, J; Allen, A; Cummins, E; Casey, E

    2017-07-01

    In an effort to mitigate biofouling on thin film composite membranes such as nanofiltration and reverse osmosis, a myriad of different surface modification strategies has been published. The use of silver nanoparticles (Ag-NPs) has emerged as being particularly promising. Nevertheless, the stability of these surface modifications is still poorly understood, particularly under permeate flux conditions. Leaching or elution of Ag-NPs from the membrane surface can not only affect the antimicrobial characteristics of the membrane, but could also potentially present an environmental liability when applied in industrial-scale systems. This study sought to investigate the dynamics of silver elution and the bactericidal effect of an Ag-NP functionalised NF270 membrane. Inductively coupled plasma-atomic emission spectroscopy was used to show that the bulk of leached silver occurred at the start of experimental runs, and was found to be independent of salt or permeate conditions used. Cumulative amounts of leached silver did, however, stabilise following the initial release, and were shown to have maintained the biocidal characteristics of the modified membrane, as observed by a higher fraction of structurally damaged Pseudomonas fluorescens cells. These results highlight the need to comprehensively assess the time-dependent nature of bactericidal membranes.

  2. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films; Potencial de degradacao fotocatalitica do diclofenaco potassico utilizando filmes finos de dioxido de titanio modificado com escandio e prata

    Energy Technology Data Exchange (ETDEWEB)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A., E-mail: rafaelciola@hotmail.com [Universidade Estadual de Mato Grosso do Sul (UFMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  3. ANTIFUNGAL ACTIVITY OF SILVER NANOPARTICLES OBTAINED BY GREEN SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Eduardo José J. MALLMANN

    2015-04-01

    Full Text Available Silver nanoparticles (AgNPs are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment.

  4. Molecular weight evaluation of poly-dimethylsiloxane on solid surfaces using silver deposition/TOF-SIMS

    Science.gov (United States)

    Inoue, Masae; Murase, Atsushi

    2004-06-01

    Molecular ions include information about end groups, functional groups and molecular weight. A method for directly detecting this in the high-mass region of the spectrum (>1000 amu) from poly-dimethylsiloxane (PDMS) on a solid surface was investigated. It was found that a TOF-SIMS analysis of silver-deposited surfaces (silver deposition/TOF-SIMS) is useful for this purpose. Two methods for silver deposition, the diode sputtering method and the vacuum evaporation coating method, were tried. The former required the sample to be cooled so as to prevent the damage of the sample surface due to thermal oxidation; the latter caused no damage to sample surfaces at room temperature. Using silver deposition/TOF-SIMS analysis, silver-cationized quasi-molecular ions were clearly detected from PDMS on solid surfaces and their images were observed without the interference of deposited silver. By applying to the analysis of paint defects, etc., it was confirmed that this technique is useful to analyze practical industrial materials. Silver-cationized ions were detected not only from PDMS, but also from other organic materials, such as some kinds of lubricant additives and fluorine oils on solid surfaces. Therefore, silver deposition/TOF-SIMS was proved to be useful for the analysis of thin substances on solid surfaces.

  5. Antioxidant properties of biohybrids based on liposomes and sage silver nanoparticles.

    Science.gov (United States)

    Barbinta-Patrascu, Marcela Elisabeta; Bunghez, Ioana-Raluca; Iordache, Stefan Marian; Badea, Nicoleta; Fierascu, Radu-Claudiu; Ion, Rodica Mariana

    2013-03-01

    This paper is aimed to describe a simple and rapid eco-friendly bottom-up approach for the preparation of antioxidant silver bionanostructures using a leaf extract from sage (Salvia officinalis L.). The bioreduction property of sage in the synthesis of silver nanoparticles was investigated by UV-VIS and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy. During their preparation, the particle size analysis was performed by using Dynamic Light Scattering technique. Ultrasonic irradiation was used to obtain sage silver nanoparticles. The morphology (size and shape) of the herbal silver nanoparticles was evaluated by Scanning Electron Microscopy that revealed the formation of spherical phytonanoparticles with size less than 80 nm. In order to increase their stability and their biocompatibility, the sage silver nanoparticles were introduced in two types of liposomes: soybean lecithin- and Chla-DPPC-lipid vesicles which were prepared by thin film hydration method. X-Ray Fluorescence analysis confirmed the silver presence in liposomes/sage-AgNPs biohybrids. The stability of liposomes/herbal AgNPs bioconstructs was checked by zeta potential measurements. The most stable biohybrids: Chla-DPPC/sage-AgNPs with zeta potential value of -34.2 mV, were characterized by Atomic Force Microscopy revealing the spherical and quasi-spherical shaped profiles of these nanobiohybrids with size less than 96 nm. The antioxidant activity of the silver bionanostructures was evaluated using chemiluminescence assay. The developed eco-friendly silver phytonanostructures based on lipid membranes, nanosilver and sage extract, manifest strong antioxidant properties (between 86.5% and 98.6%).

  6. Green synthesis of silver nanoparticles and silver colloidal solutions

    International Nuclear Information System (INIS)

    Nguyen Thi Phuong Phong; Ngo Hoang Minh; Ngo Vo Ke Thanh; Dang Mau Chien

    2009-01-01

    In this paper, silver colloidal solutions have been synthesized rapidly in green conditions by using microwave irradiation and non-toxic chemistry substances (acid oxalic, silver nitrate, polyvinyl pyrolidone (PVP; Mw = 55 000)). The particle size and morphology of these solutions can be controlled by altering several factors like the time, the power of microwave exposure, and the ratio of silver oxalate and PVP etc. The silver nanoparticles were fabricated by thermal decomposition of silver oxalate. The synthesized silver colloidal solutions and silver nanoparticles were characterized by several analytical techniques like UV- VIS, XRD, TEM, FESEM/EDS and ICP-AAS studies. Finally, we used the synthesized silver colloidal solutions for antibacterial purpose. The obtained results showed that the synthesized silver colloidal solutions, even at very low concentrations, have highly efficient anti-bacterial property.

  7. Fabrication of Au/graphene oxide/Ag sandwich structure thin film and its tunable energetics and tailorable optical properties

    Directory of Open Access Journals (Sweden)

    Ruijin Hong

    2017-01-01

    Full Text Available Au/graphene oxide/Ag sandwich structure thin film was fabricated. The effects of graphene oxide (GO and bimetal on the structure and optical properties of metal silver films were investigated by X-ray diffraction (XRD, optical absorption, and Raman intensity measurements, respectively. Compared to silver thin film, Au/graphene oxide/Ag sandwich structure composite thin films were observed with wider optical absorption peak and enhanced absorption intensity. The Raman signal for Rhodamine B molecules based on the Au/graphene oxide/Ag sandwich nanostructure substrate were obviously enhanced due to the bimetal layer and GO layer with tunable absorption intensity and fluorescence quenching effects.

  8. Dynamics at the nanoscale

    International Nuclear Information System (INIS)

    Stoneham, A.M.; Gavartin, J.L.

    2007-01-01

    However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

  9. Synthesis and characterization of nano silver ferrite composite

    International Nuclear Information System (INIS)

    Murthy, Y.L.N.; Kondala Rao, T.; Kasi viswanath, I.V.; Singh, Rajendra

    2010-01-01

    We report the synthesis of nano sized silver ferrite composite having the empirical formula AgFeO 2 by a co-precipitation method. The resulting powders are thin platelets, transparent and a rich ruby red in color in transmission. The X-ray diffraction (XRD) powder data consisted of only nine reflections, and the analysis showed the unit cell to be rhombohedral. The powders showed extensive XRD line broadening and the sizes of the crystals are calculated to be in the range 4-36.5 nm. The morphology of the silver ferrite composite studied using scanning electron microscope showed nano sized particles. The particle size is found to increase with increase in annealing temperature. The magnetic behavior, measured using a vibrating sample magnetometer, indicated a change from paramagnetic to ferromagnetic with increase in particle size.

  10. Ultra-thin layer chromatography and surface enhanced Raman spectroscopy on silver nanorod array substrates prepared by oblique angle deposition

    Science.gov (United States)

    Chen, Jing; Abell, Justin; Huang, Yao-wen; Zhao, Yiping

    2012-06-01

    We demonstrate the potential use of silver nanorod (AgNR) array substrates for on-chip separation and detection of chemical mixtures by ultra-thin layer chromatography (UTLC) and surface enhanced Raman spectroscopy (SERS). The capability of the AgNR substrates to separate different compounds in a mixture was explored using a mixture of the food colorant Brilliant Blue FCF and lactic acid, and the mixtures of Methylene Violet and BSA at various concentrations. After the UTLC process, spatially-resolved SERS spectra were collected along the mobile phase development direction and the intensities of specific SERS peaks from each component were used to generate chromatograms. The AgNR substrates demonstrate the capability of separating Brilliant Blue from lactic acid, as well as revealing the SERS signal of Methylene Violet from the massive BSA background after a simple UTLC step. This technique may have significant practical implications in actual detection of small molecules from complex food or clinical backgrounds.

  11. Roman sophisticated surface modification methods to manufacture silver counterfeited coins

    Science.gov (United States)

    Ingo, G. M.; Riccucci, C.; Faraldi, F.; Pascucci, M.; Messina, E.; Fierro, G.; Di Carlo, G.

    2017-11-01

    By means of the combined use of X-ray photoelectron spectroscopy (XPS), optical microscopy (OM) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) the surface and subsurface chemical and metallurgical features of silver counterfeited Roman Republican coins are investigated to decipher some aspects of the manufacturing methods and to evaluate the technological ability of the Roman metallurgists to produce thin silver coatings. The results demonstrate that over 2000 ago important advances in the technology of thin layer deposition on metal substrates were attained by Romans. The ancient metallurgists produced counterfeited coins by combining sophisticated micro-plating methods and tailored surface chemical modification based on the mercury-silvering process. The results reveal that Romans were able systematically to chemically and metallurgically manipulate alloys at a micro scale to produce adherent precious metal layers with a uniform thickness up to few micrometers. The results converge to reveal that the production of forgeries was aimed firstly to save expensive metals as much as possible allowing profitable large-scale production at a lower cost. The driving forces could have been a lack of precious metals, an unexpected need to circulate coins for trade and/or a combinations of social, political and economic factors that requested a change in money supply. Finally, some information on corrosion products have been achieved useful to select materials and methods for the conservation of these important witnesses of technology and economy.

  12. Mesoporous Ruthenium/Ruthenium Oxide Thin Films: Active Electrocatalysts for the Oxygen Evolution Reaction

    DEFF Research Database (Denmark)

    Kibsgaard, Jakob; Hellstern, Thomas R.; Choi, Shin-Jung

    2017-01-01

    We report the first synthesis of a fully contiguous large area supported thin film of highly ordered mesoporous Ru and RuO2 and investigate the electrocatalytic properties towards the oxygen evolution reaction (OER). We find that the nanoscale porous network of these catalysts provides significant...... enhancements in geometric OER activity without any loss in specific activity. This work demonstrates a strategy for engineering materials at the nanoscale that can simultaneously decrease precious metal loading and increase electrode activity....

  13. On the problem of soldering refractory metals with silver-containing solders

    International Nuclear Information System (INIS)

    Anikeev, E.F.; Andryushchenko, V.I.; Chepelenko, V.N.; Batov, V.M.

    1981-01-01

    The processes of wetting, spreading and interphase interactions of copper-silver liquid alloys alloyed with Ni and Si, with niobium, tantalum, molybdenum, tungsten, 12Kh18N10T steel and nickel are studied. It has been determined that Ni or Si additions into the copper-silver solder improve the wetting and adhesion. When soldering with the alloy containing Ni additions, the strength of a soldered Joint grows with the increase of soldering duration while soldering with the alloy containing Si additions, the strength decreases. That is why Ni-containing solders are preferable for soldering thick-walled structures, and Si-containing solders - for thin-walled structures [ru

  14. Modulated surface textures for enhanced scattering in thin-film silicon solar cells

    NARCIS (Netherlands)

    Isabella, O.; Battaglia, C.; Ballif, C.; Zeman, M.

    2012-01-01

    Nano-scale randomly textured front transparent oxides are superposed on micro-scale etched glass substrates to form modulated surface textures. The resulting enhanced light scattering is implemented in single and double junction thin-film silicon solar cells.

  15. Preconcentration of silver as silver xanthate on activated carbon

    International Nuclear Information System (INIS)

    Ramadevi, P.; Naidu, U.V.; Naidu, G.R.K.

    1988-01-01

    Silver from aqueous solution was preconcentrated by adsorption on activated carbon as silver xanthate. Factors influencing the adsorption of silver were studied. Optimum conditions for the preconcentration of silver were established. (author) 9 refs.; 3 tabs

  16. Impact of the substrate on the efficiency of thin film thermoelectric technology

    International Nuclear Information System (INIS)

    Alvarez-Quintana, J.

    2015-01-01

    Thermoelectricity is one of the simplest technologies for thermal energy conversion. Moreover, because of their relatively low efficiency, bulk thermoelectric materials are generally used in environments where their solid state nature outweighs their poor efficiency. Nevertheless, low dimensional thermoelectric materials shed a light in order to achieve higher thermoelectric performance than their bulk counterparts via quantum and spatial confinement of energy carriers. The Thermoelectric figure of merit ZT is the basic criterion for estimating the performance of thermoelectric materials. In this work, by way of an extension of the Harman method to thin films onto substrate to evaluate ZT it is shown that the solely presence of a substrate affects significantly the intrinsic value of the ZT independently of the electrical and thermal nature of the substrate. Furthermore, the model unveils that as the thickness ratio between substrate and thin film increases, the parameter ZT sharply tends to zero; this effect opens a serious problem to overcome by the thin film thermoelectric technology, especially at nanoscale. In this sense, challenges in order to engineering planar thermoelectric devices at micro/nanoscale are properly identified. - Highlights: • Extended Harman method to evaluate ZT of thin films onto substrate is presented. • ZT of thermoelectric thin films is strongly affected by substrate's nature. • Thin dielectric substrates are desirable to hold ZT in in-plane configuration. • Film/substrate thickness ratio play important role on the device performance. • Challenges to engineering planar thermoelectric devices are properly identified

  17. Manipulation and light-induced agglomeration of carbon nanotubes through optical trapping of attached silver nanoparticles

    International Nuclear Information System (INIS)

    Shi Chao; Zhang Yi; Gu, Claire; Seballos, Leo; Zhang, Jin Z

    2008-01-01

    A simple experimental method has been demonstrated for manipulating multi-walled carbon nanotube (MWCNT) bundles through the optical trapping of attached silver nanoparticles (SNPs). In our experiments, without the SNPs, the MWCNTs cannot be trapped due to their irregular shapes and large aspect ratio. However, when mixed with SNPs, the MWCNTs can be successfully trapped along with the SNPs using a TEM 00 mode laser at 532 nm. This is attributed to the optical trapping of the SNPs and attractive interaction or binding between the SNPs and MWCNTs due to electrostatic and van der Waals forces. Therefore, optical manipulation of MWCNT bundles is achieved through the manipulation of the attached silver nanoparticles/aggregates. In addition, we have observed the phenomenon of light-induced further agglomeration of SNPs/MWCNTs which could potentially be exploited for fabricating patterned MWCNT films for future nanoscale devices and other applications

  18. Ambipolar transport of silver nanoparticles decorated graphene oxide field effect transistors

    Science.gov (United States)

    Sarkar, Kalyan Jyoti; Sarkar, K.; Pal, B.; Kumar, Aparabal; Das, Anish; Banerji, P.

    2018-05-01

    In this article, we report ambipolar field effect transistor (FET) by using graphene oxide (GO) as a gate dielectric material for silver nanoparticles (AgNPs) decorated GO channel layer. GO was synthesized by Hummers' method. The AgNPs were prepared via photochemical reduction of silver nitrate solution by using monoethanolamine as a reducing agent. Morphological properties of channel layer were characterized by Field Effect Scanning Electron Microscopy (FESEM). Fourier Transform Infrared Spectroscopy (FTIR) was carried out to characterize GO thin film. For device fabrication gold (Au) was deposited as source-drain contact and aluminum (Al) was taken as bottom contact. Electrical measurements were performed by back gate configuration. Ambipolar transport behavior was explained from transfer characteristics. A maximum electron mobiliy of 6.65 cm2/Vs and a hole mobility of 2.46 cm2/Vs were extracted from the transfer characteristics. These results suggest that GO is a potential candidate as a gate dielectric material for thin film transistor applications and also provides new insights in GO based research.

  19. Silver-doped layers of implants prepared by pulsed laser deposition

    Czech Academy of Sciences Publication Activity Database

    Kocourek, Tomáš; Jelínek, Miroslav; Mikšovský, Jan; Jurek, Karel; Čejka, Z.; Kopeček, Jaromír

    2013-01-01

    Roč. 1, č. 7 (2013), s. 59-61 ISSN 2327-5219 R&D Projects: GA AV ČR KAN300100801 Institutional support: RVO:68378271 Keywords : thin layer * silver * titanium alloy * steel * pulsed laser deposition * adhesion * implant Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.scirp.org/journal/PaperInformation.aspx?paperID=40308#.UvECAfu5dHA

  20. Silver film on nanocrystalline TiO{sub 2} support: Photocatalytic and antimicrobial ability

    Energy Technology Data Exchange (ETDEWEB)

    Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Tomašević-Ilić, Tijana D., E-mail: tommashev@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Zarubica, Aleksandra R., E-mail: zarubica2000@yahoo.com [Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš (Serbia); Dimitrijević, Suzana, E-mail: suzana@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Budimir, Milica D., E-mail: mickbudimir@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Vranješ, Mila R., E-mail: mila@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Šaponjić, Zoran V., E-mail: saponjic@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

    2014-12-15

    Highlights: • Simple photocatalytic rout for deposition of Ag on nanocrystalline TiO{sub 2} films. • High antibactericidal efficiency of deposited Ag on TiO{sub 2} support. • Improved photocatalytic performance of TiO{sub 2} films in the presence of deposited Ag. - Abstract: Nanocrystalline TiO{sub 2} films were prepared on glass slides by the dip coating technique using colloidal solutions consisting of 4.5 nm particles as a precursor. Photoirradiation of nanocrystalline TiO{sub 2} film modified with alanine that covalently binds to the surface of TiO{sub 2} and at the same time chelate silver ions induced formation of metallic silver film. Optical and morphological properties of thin silver films on nanocrystalline TiO{sub 2} support were studied by absorption spectroscopy and atomic force microscopy. Improvement of photocatalytic performance of nanocrystalline TiO{sub 2} films after deposition of silver was observed in degradation reaction of crystal violet. Antimicrobial ability of deposited silver films on nanocrystalline TiO{sub 2} support was tested in dark as a function of time against Escherichia coli, Staphylococcus aureus, and Candida albicans. The silver films ensured maximum cells reduction of both bacteria, while the fungi reduction reached satisfactory 98.45% after 24 h of contact.

  1. Inkjet-printed transparent nanowire thin film features for UV photodetectors

    KAUST Repository

    Chen, Shih Pin; Duran Retamal, Jose Ramon; Lien, Der Hsien; He, Jr-Hau; Liao, Ying Chih

    2015-01-01

    In this study, a simple and effective direct printing method was developed to print patterned nanowire thin films for UV detection. Inks containing silver or titanium dioxide (TiO2) nanowires were first formulated adequately to form stable

  2. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    International Nuclear Information System (INIS)

    Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R; Kolar, M

    2011-01-01

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  3. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    Energy Technology Data Exchange (ETDEWEB)

    Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R [Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, 17. Listopadu 12, 77146 Olomouc (Czech Republic); Kolar, M, E-mail: ales.panacek@upol.cz [Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77520 Olomouc (Czech Republic)

    2011-07-06

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  4. Nanoscale imaging of photocurrent enhancement by resonator array photovoltaic coatings

    Science.gov (United States)

    Ha, Dongheon; Yoon, Yohan; Zhitenev, Nikolai B.

    2018-04-01

    Nanoscale surface patterning commonly used to increase absorption of solar cells can adversely impact the open-circuit voltage due to increased surface area and recombination. Here, we demonstrate absorptivity and photocurrent enhancement using silicon dioxide (SiO2) nanosphere arrays on a gallium arsenide (GaAs) solar cell that do not require direct surface patterning. Due to the combined effects of thin-film interference and whispering gallery-like resonances within nanosphere arrays, there is more than 20% enhancement in both absorptivity and photocurrent. To determine the effect of the resonance coupling between nanospheres, we perform a scanning photocurrent microscopy based on a near-field scanning optical microscopy measurement and find a substantial local photocurrent enhancement. The nanosphere-based antireflection coating (ARC), made by the Meyer rod rolling technique, is a scalable and a room-temperature process; and, can replace the conventional thin-film-based ARCs requiring expensive high-temperature vacuum deposition.

  5. Paper-based transparent flexible thin film supercapacitors

    Science.gov (United States)

    Gao, Kezheng; Shao, Ziqiang; Wu, Xue; Wang, Xi; Zhang, Yunhua; Wang, Wenjun; Wang, Feijun

    2013-05-01

    Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm-2), and a transmittance of about 56% (at 550 nm).Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm-2), and a transmittance of about 56% (at 550 nm). Electronic supplementary information (ESI) available: Experimental, TEM image, IR spectra, and XRD spectra of cellulose nanofibers, TEM image, and XRD spectra of RGO, graphite, GO nanosheets, CNF paper, and CNF-[RGO]20 hybrid paper, high-resolution C1s spectra of GO, Raman spectra of GO nanosheets, cross-sectional FESEM image of CNF-[RGO]20 hybrid paper and stress-strain curve of T-SC-20. See DOI: 10.1039/c3nr00674c

  6. Antibacterial, cytotoxicity and physical properties of laser - silver doped hydroxyapatite layers

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Kocourek, Tomáš; Remsa, Jan; Weiserová, Marie; Jurek, Karel; Mikšovský, Jan; Strnad, J.; Galandáková, A.; Ulrichová, J.

    2013-01-01

    Roč. 33, č. 3 (2013), s. 1242-1246 ISSN 0928-4931 R&D Projects: GA MŠk LD12069 Institutional support: RVO:68378271 ; RVO:61388971 Keywords : hydroxyapatite * silver * thin films * PLD * antibacterial * cytotoxicity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.736, year: 2013 http://dx.doi.org/10.1016/j.msec.2012.12.018

  7. Nanoscale reduction of graphene oxide thin films and its characterization

    KAUST Repository

    Lorenzoni, M.; Giugni, Andrea; Di Fabrizio, Enzo M.; Pé rez-Murano, Francesc; Mescola, A.; Torre, Bruno

    2015-01-01

    In this paper, we report on a method to reduce thin films of graphene oxide (GO) to a spatial resolution better than 100 nm over several tens of micrometers by means of an electrochemical scanning probe based lithography. In situ tip

  8. A Review of Atomic Layer Deposition for Nanoscale Devices

    Directory of Open Access Journals (Sweden)

    Edy Riyanto

    2012-12-01

    Full Text Available Atomic layer deposition (ALD is a thin film growth technique that utilizes alternating, self-saturation chemical reactions between gaseous precursors to achieve a deposited nanoscale layers. It has recently become a subject of great interest for ultrathin film deposition in many various applications such as microelectronics, photovoltaic, dynamic random access memory (DRAM, and microelectromechanic system (MEMS. By using ALD, the conformability and extreme uniformity of layers can be achieved in low temperature process. It facilitates to be deposited onto the surface in many variety substrates that have low melting temperature. Eventually it has advantages on the contribution to the wider nanodevices.

  9. Thin films of metal-organic compounds and metal nanoparticle ...

    Indian Academy of Sciences (India)

    Optical limiting capability of the nanoparticle-embedded polymer film is demonstrated. Keywords. Polar crystal; uniaxial orientational order; thin film; second harmonic gen- eration; silver ... able content of metal nanoparticles would be of considerable value from an appli- ... polar chain and perpendicular to it [10].

  10. Characterization of Ag-doped vanadium oxide (AgxV2O5) thin film for cathode of thin film battery

    International Nuclear Information System (INIS)

    Hwang, H.S.; Oh, S.H.; Kim, H.S.; Cho, W.I.; Cho, B.W.; Lee, D.Y.

    2004-01-01

    The effect of silver co-sputtering on the characteristics of amorphous V 2 O 5 films, grown by dc reactive sputtering, is investigated. The co-sputtering process influences the growth mechanism as well as the characteristics of the V 2 O 5 films. X-ray diffraction (XRD), Inductively coupled plasma-atomic emission spectrometry (ICP-AES), field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectrometry (XPS) results indicate that the microstructure of the V 2 O 5 films is affected by the rf power of the co-sputtered silver. In addition, an all-solid-state thin film battery with full cell structure of Li/LiPON/Ag x V 2 O 5 /Pt has been fabricated. It is found that the silver co-sputtered V 2 O 5 cathode film exhibits better cycle performance than an undoped one

  11. Controlling the optical parameters of self-assembled silver films with wetting layers and annealing

    Science.gov (United States)

    Ciesielski, Arkadiusz; Skowronski, Lukasz; Trzcinski, Marek; Szoplik, Tomasz

    2017-11-01

    We investigated the influence of presence of Ni and Ge wetting layers as well as annealing on the permittivity of Ag films with thicknesses of 20, 35 and 65 nm. Most of the research on thin silver films deals with very small (wetting and capping material, post-process annealing). Our study, based on atomic force microscopy, ellipsometric and X-ray photoelectron spectroscopy measurements, shows that utilizing a wetting layer is comparable to increasing the thickness of the silver film. Both operations decrease the roughness-to-thickness ratio, thus decreasing the scattering losses and both narrow the Lorentz-shaped interband transition peak. However, while increasing silver thickness increases absorption on the free carriers, the use of wetting layers influences the self-assembled internal structure of silver films in such a way, that the free carrier absorption decreases. Wetting layers also introduce additional contributions from effects like segregation or diffusion, which evolve in time and due to annealing.

  12. Ambiance-dependent agglomeration and surface-enhanced Raman spectroscopy response of self-assembled silver nanoparticles for plasmonic photovoltaic devices

    Science.gov (United States)

    Gwamuri, Jephias; Venkatesan, Ragavendran; Sadatgol, Mehdi; Mayandi, Jeyanthinath; Guney, Durdu O.; Pearce, Joshua M.

    2017-07-01

    The agglomeration/dewetting process of thin silver films provides a scalable method of obtaining self-assembled nanoparticles (SANPs) for plasmonics-based thin-film solar photovoltaic (PV) devices. We show the effect of annealing ambiance on silver SANP average size, particle/cluster finite shape, substrate area coverage/particle distribution, and how these physical parameters influence optical properties and surface-enhanced Raman scattering (SERS) responses of SANPs. Statistical analysis performed indicates that generally Ag SANPs processed in the presence of a gas (argon and nitrogen) ambiance tend to have smaller average size particles compared to those processed under vacuum. Optical properties are observed to be highly dependent on particle size, separation distance, and finite shape. The greatest SERS enhancement was observed for the argon-processed samples. There is a correlation between simulation and experimental data that indicate argon-processed AgNPs have a great potential to enhance light coupling when integrated to thin-film PV.

  13. Bactericidal performance of visible-light responsive titania photocatalyst with silver nanostructures.

    Directory of Open Access Journals (Sweden)

    Ming-Show Wong

    Full Text Available BACKGROUND: Titania dioxide (TiO(2 photocatalyst is primarily induced by ultraviolet light irradiation. Visible-light responsive anion-doped TiO(2 photocatalysts contain higher quantum efficiency under sunlight and can be used safely in indoor settings without exposing to biohazardous ultraviolet light. The antibacterial efficiency, however, remains to be further improved. METHODOLOGY/PRINCIPAL FINDINGS: Using thermal reduction method, here we synthesized silver-nanostructures coated TiO(2 thin films that contain a high visible-light responsive antibacterial property. Among our tested titania substrates including TiO(2, carbon-doped TiO(2 [TiO(2 (C] and nitrogen-doped TiO(2 [TiO(2 (N], TiO(2 (N showed the best performance after silver coating. The synergistic antibacterial effect results approximately 5 log reductions of surviving bacteria of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Acinetobacter baumannii. Scanning electron microscope analysis indicated that crystalline silver formed unique wire-like nanostructures on TiO(2 (N substrates, while formed relatively straight and thicker rod-shaped precipitates on the other two titania materials. CONCLUSION/SIGNIFICANCE: Our results suggested that proper forms of silver on various titania materials could further influence the bactericidal property.

  14. Rocket Science at the Nanoscale.

    Science.gov (United States)

    Li, Jinxing; Rozen, Isaac; Wang, Joseph

    2016-06-28

    Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way for designing multifunctional and intelligent nanoscale machines. These multipurpose nanoscale shuttles can propel and function in complex real-life media, actively transporting and releasing therapeutic payloads and remediation agents for diverse biomedical and environmental applications. This review discusses the challenges of designing efficient MNRs and presents an overview of their propulsion behavior, fabrication methods, potential rocket fuels, navigation strategies, practical applications, and the future prospects of rocket science and technology at the nanoscale.

  15. Intrinsic and extrinsic resistive switching in a planar diode based on silver oxide nanoparticles

    NARCIS (Netherlands)

    Kiazadeh, A.; Gomes, H.L.; Rosa da Costa, A.M.; Moreira, J.A.; Leeuw, de D.M.; Meskers, S.C.J.

    2012-01-01

    Resistive switching is investigated in thin-film planar diodes using silver oxide nanoparticles capped in a polymer. The conduction channel is directly exposed to the ambient atmosphere. Two types of switching are observed. In air, the hysteresis loop in the current–voltage characteristics is

  16. Visualization of silver-decorated poly (DL-lactide-co-glycolide) nanoparticles and their efficacy against Staphylococcus epidermidis

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato, E-mail: chisato@dpc.agu.ac.jp [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Matsubara, Nobuhiro; Akachi, Yuki; Ogawa, Noriko [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Kalita, Golap [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Asaka, Toru [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, Masaki [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Kawashima, Yoshiaki; Yamamoto, Hiromitsu [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan)

    2017-03-01

    Understanding of self-protection activity of the bacteria and interaction with drug substances has significant importance for designing of effective drug delivery system for treatment of biofilm infections. Recently silver nanoparticle has attracted attention as antibacterial substance for drug delivery system because of its high antibacterial activity. Here, efflux of silver nanoparticles obtained from within the prepared silver-decorated poly (DL-lactide-co-glycolide) (Ag PLGA) nanoparticles derived from Staphylococcus epidermidis bacterial cell was successfully visualized using scanning transmission electron microscopy (STEM). We also revealed the interaction between prepared Ag PLGA nanoparticles and the bacterial cells at the nanoscale level using field emission scanning electron microscopy and STEM, after a pretreatment process by an ionic liquid. This finding is significant to understand a fundamental function of S. epidermidis bacterial cells, which is not explored previously. The results suggest that Ag PLGA nanoparticles could demonstrate high efficacy against biofilm infections. - Highlights: • Ag PLGA nanoparticles with high efficacy against biofilm infections were prepared. • Self-protection activity of bacteria against Ag nanoparticles was visualized by STEM. • Antibacterial mechanism of Ag PLGA nanoparticles against biofilm was proposed.

  17. A surface evolution scheme to identify nanoscale intrinsic geometry from AFM experimental data

    International Nuclear Information System (INIS)

    Jang, Hong-Lae; Kim, Hyun-Seok; Park, Youmie; Cho, Seonho

    2013-01-01

    The geometrical properties of metallic nanoparticles such as the size and morphology have significant impacts on the structure and stability of the adsorbed biological entities as well as the nanoscale structural performances. To identify the nanoscale intrinsic geometry from the height images by atomic force microscopy (AFM), we developed a curvature-dependent evolution scheme that can eliminate the noise and smoothen the surfaces. The principal curvatures are computed directly from the first and second derivatives of the discrete AFM height data. The principal curvatures and directions correspond to the eigenvalues and eigenvectors of shape operator matrix, respectively. The evolution equation using the principal curvature flows smoothens the images in the corresponding principal directions. For an idealized model, κ 2 flow successfully identifies the major valley lines to represent the boundary of nanoparticles without referring to the phase information, whereas the mean curvature flow eliminates all the minor ones leaving only the major feature of the boundary. To demonstrate the capability of noise removal, smoothing surfaces, the identification of ridge and valley lines, and the extraction of intrinsic geometry, the developed numerical scheme is applied to real AFM data that include the silver nanoparticles of 24 nm diameter and the gold nanoparticles of 33–56 nm diameters

  18. Measurement of the dynamic behavior of thin poly(N-isopropylacrylamide) hydrogels and their phase transition temperatures measured using reflectometric interference spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Fuminori [Konica Minolta, INC. (Japan); Akiyama, Yoshikatsu, E-mail: akiyama.yoshikatsu@twmu.ac.jp, E-mail: akiyama.yoshikatsu@abmes.twmu.ac.jp; Kobayashi, Jun [Tokyo Women’s Medical University (TWIns), Institute of Advanced Biomedical Engineering and Science (Japan); Ninomiya, Hidetaka [Konica Minolta, INC. (Japan); Kanazawa, Hideko [Keio University, Faculty of Pharmacy (Japan); Yamato, Masayuki; Okano, Teruo [Tokyo Women’s Medical University (TWIns), Institute of Advanced Biomedical Engineering and Science (Japan)

    2015-03-15

    Temperature-responsive cell culture surfaces prepared by modifying tissue-culture polystyrene with nanoscale poly(N-isopropylacrylamide) (PIPAAm) hydrogels are widely used as intelligent surfaces for the fabrication of various cell sheets that change with temperature. In this work, the characteristics of nanoscale PIPAAm hydrogels were phenomenologically elucidated on the basis of time-dependent surface evaluations under conditions of changing temperature. Because the dynamic characteristics of the nanoscale hydrogel did not exhibit good performance, the nanoscale PIPAAm hydrogel was analyzed by monitoring its temperature-dependent dynamic swelling/deswelling changes using reflectometric interference spectroscopy (RIfS) on an instrument equipped with a microfluidic system. RIfS measurements under ambient atmosphere provided the precise physical thickness of the dry PIPAAm hydrogel (6.7 nm), which agreed with the atomic force microscopy results (6.6 nm). Simulations of the reflectance spectra revealed that changes in the wavelength of the minimum reflectance (Δλ) were attributable to the changes in the refractive index of the thin PIPAAm hydrogel induced by a temperature-dependent volume phase transition. The temperature-dependent Δλ change was used to monitor the swelling/deswelling behavior of the nanoscale PIPAAm hydrogel. In addition, the phase transition temperature of the thin PIPAAm hydrogel under aqueous conditions was also determined to be the inflection point of the plot of the change in Δλ as a function of temperature. The dynamic behavior of a thin PIPAAm hydrogel chemically deposited on a surface was readily analyzed using a new analytical system with RIfS and microfluidic devices.

  19. Laser-assisted immobilization of colloid silver nanoparticles on polyethyleneterephthalate

    Science.gov (United States)

    Siegel, Jakub; Lyutakov, Oleksiy; Polívková, Markéta; Staszek, Marek; Hubáček, Tomáš; Švorčík, Václav

    2017-10-01

    Immobilization of nanoobjects on the surface of underlying material belongs to current issues of material science. Such altered materials exhibits completely exceptional properties exploitable in a broad spectrum of industrially important applications ranging from catalysts up to health-care industry. Here we present unique approach for immobilization of electrochemically synthesized silver nanoparticles on polyethyleneterephthalate (PET) foil whose essence lies in physical incorporation of particles into thin polymer surface layer induced by polarized excimer laser light. Changes in chemical composition and surface structure of polymer after particle immobilization were recorded by wide range of analytical techniques such as ARXPS, EDX, RBS, AAS, Raman, ICP-MS, DLS, UV-vis, SEM, TEM, and AFM. Thorough analysis of both nanoparticles entering the immobilization step as well as modified PET surface allowed revealing the mechanism of immobilization process itself. Silver nanoparticles were physically embedded into a thin surface layer of polymer reaching several nanometers beneath the surface rather than chemically bonded to PET macromolecules. Laser-implanted nanoparticles open up new possibilities especially in the development of the next generation cell-conform antimicrobial coatings of polymeric materials, namely due to the considerable immobilization strength which is strong enough to prevent particle release into the surrounding environment.

  20. AgSbSe2 and AgSb(S,Se)2 thin films for photovoltaic applications

    International Nuclear Information System (INIS)

    Garza, J.G.; Shaji, S.; Rodriguez, A.C.; Das Roy, T.K.; Krishnan, B.

    2011-01-01

    Silver antimony selenide (AgSbSe 2 ) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb 2 S 3 ), silver selenide (Ag 2 Se), selenium (Se) and silver (Ag). Sb 2 S 3 thin film was prepared from a chemical bath containing SbCl 3 and Na 2 S 2 O 3 , Ag 2 Se from a solution containing AgNO 3 and Na 2 SeSO 3 and Se thin films from an acidified solution of Na 2 SeSO 3 , at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10 -3 Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe 2 or AgSb(S,Se) 2 depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe 2 /Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V oc = 435 mV and J sc = 0.08 mA/cm 2 under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe 2 as an absorber material by a non-toxic selenization process is achieved.

  1. Oral toxicity of silver ions, silver nanoparticles and colloidal silver--a review.

    Science.gov (United States)

    Hadrup, Niels; Lam, Henrik R

    2014-02-01

    Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least a factor of five before a level of concern to the general population is reached. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Oral toxicity of silver ions, silver nanoparticles and colloidal silver – a review

    DEFF Research Database (Denmark)

    Hadrup, Niels; Lam, Henrik Rye

    2014-01-01

    Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin......, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts...... and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least...

  3. Experimental Study of Electron and Phonon Dynamics in Nanoscale Materials by Ultrafast Laser Time-Domain Spectroscopy

    Science.gov (United States)

    Shen, Xiaohan

    less than 100 nm was observed. The longitudinal acoustic phonon transport in silicon (Si) nanorod with confined diameter and length was investigated. The guided phonon modes in Si nanorod with different frequencies and wave vectors were observed. The mean-free-path of the guided phonons in Si nanorod was found to be larger than the effective phonon mean-free-path in Si film, because of the limited phonon scattering channels in Si nanorod. The phonon density of states and dispersion relation strongly depend on the size and boundary conditions of nanorod. Our work demonstrates the possibility of modifying the phonon transport properties in nanoscale materials by designing the size and boundary conditions, hence the control of thermal conductivity. In addition, the periodicity effect of nanostructures on acoustic phonon transport was investigated in silicon dioxide (SiO2) nanorod arrays. The lattice modes and mechanical eigenmodes were observed, and the pitch effect on lattice modes was discussed. A narrowband acoustic phonon spectroscopic technique with tunable frequency and spectral width throughout GHz frequency range has been developed to investigate the frequency-dependent acoustic phonon transport in nanoscale materials. The quadratic frequency dependence of acoustic attenuation of SiO2 and indium tin oxide (ITO) thin films was observed, and the acoustic attenuation of ITO was found to be larger than SiO2. Moreover, the acoustic control on mechanical resonance of nanoscale materials using the narrowband acoustic phonon source was demonstrated in tungsten thin film.

  4. The Anti-Fasciolasis Properties of Silver Nanoparticles Produced by Trichoderma harzianum and Their Improvement of the Anti-Fasciolasis Drug Triclabendazole

    Directory of Open Access Journals (Sweden)

    AbdelElah A. Banaja

    2013-11-01

    Full Text Available Recently, new strains of Fasciola demonstrated drug resistance, which increased the need for new drugs or improvement of the present drugs. Nanotechnology is expected to open some new opportunities to fight and prevent diseases using an atomic scale tailoring of materials. The ability to uncover the structure and function of biosystems at the nanoscale, stimulates research leading to improvement in biology, biotechnology, medicine and healthcare. The size of nanomaterials is similar to that of most biological molecules and structures; therefore, nanomaterials can be useful for both in vivo and in vitro biomedical research and applications. Therefore, this work aimed to isolate fungal strains from Taif soil samples, which have the ability to synthesize silver nanoparticles. The fungus Trichoderma harzianum, when challenged with silver nitrate solution, accumulated silver nanoparticles (AgNBs on the surface of its cell wall in 72 h. These nanoparticles, dislodged by ultrasonication, showed an absorption peak at 420 nm in a UV-visible spectrum, corresponding to the plasmon resonance of silver nanoparticles. The transmission electron micrographs of dislodged nanoparticles in aqueous solution showed the production of reasonably monodisperse silver nanoparticles (average particle size: 4.66 nm by the fungus. The percentage of non hatching eggs treated with the Triclabendazole drug was 69.67%, while this percentage increased to 89.67% in combination with drug and AgNPs.

  5. Nanoscale Ionic Liquids

    Science.gov (United States)

    2006-11-01

    Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

  6. Nanoscale electron transport at the surface of a topological insulator

    Science.gov (United States)

    Bauer, Sebastian; Bobisch, Christian A.

    2016-04-01

    The use of three-dimensional topological insulators for disruptive technologies critically depends on the dissipationless transport of electrons at the surface, because of the suppression of backscattering at defects. However, in real devices, defects are unavoidable and scattering at angles other than 180° is allowed for such materials. Until now, this has been studied indirectly by bulk measurements and by the analysis of the local density of states in close vicinity to defect sites. Here, we directly measure the nanoscale voltage drop caused by the scattering at step edges, which occurs if a lateral current flows along a three-dimensional topological insulator. The experiments were performed using scanning tunnelling potentiometry for thin Bi2Se3 films. So far, the observed voltage drops are small because of large contributions of the bulk to the electronic transport. However, for the use of ideal topological insulating thin films in devices, these contributions would play a significant role.

  7. Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

    Energy Technology Data Exchange (ETDEWEB)

    Abdellatif, M.H. [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Physics Department, National Research Center, Elbehoos st., 12622, Dokki, Giza (Egypt); Salerno, M., E-mail: marco.salerno@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Polovitsyn, Anatolii [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Dipartimentodi Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova (Italy); Marras, Sergio [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); De Angelis, Francesco [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy)

    2017-05-01

    Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

  8. Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

    International Nuclear Information System (INIS)

    Abdellatif, M.H.; Salerno, M.; Polovitsyn, Anatolii; Marras, Sergio; De Angelis, Francesco

    2017-01-01

    Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

  9. Reversible migration of silver on memorized pathways in Ag-Ge40S60 films

    Directory of Open Access Journals (Sweden)

    J. Orava

    2015-07-01

    Full Text Available Reversible and reproducible formation and dissolution of silver conductive filaments are studied in Ag-photodoped thin-film Ge40S60 subjected to electric fields. A tip-planar geometry is employed, where a conductive-atomic-force microscopy tip is the tip electrode and a silver patch is the planar electrode. We highlight an inherent “memory” effect in the amorphous chalcogenide solid-state electrolyte, in which particular silver-ion migration pathways are preserved “memorized” during writing and erasing cycles. The “memorized” pathways reflect structural changes in the photodoped chalcogenide film. Structural changes due to silver photodoping, and electrically-induced structural changes arising from silver migration, are elucidated using Raman spectroscopy. Conductive filament formation, dissolution, and electron (reduction efficiency in a lateral device geometry are related to operation of the nano-ionic Programmable Metallization Cell memory and to newly emerging chalcogenide-based lateral geometry MEMS technologies. The methods in this work can also be used for qualitative multi-parameter sampling of metal/amorphous-chalcogenide combinations, characterizing the growth/dissolution rates, retention and endurance of fractal conductive filaments, with the aim of optimizing devices.

  10. Unraveling the reaction mechanism of silver ions reduction by chitosan from so far neglected spectroscopic features.

    Science.gov (United States)

    Carapeto, Ana Patrícia; Ferraria, Ana Maria; do Rego, Ana Maria Botelho

    2017-10-15

    Metallic silver nanoparticles were synthesized in aqueous solution using chitosan, as both reducing and stabilizing agent, and AgNO 3 as silver precursor aiming the production of solid ultra-thin films. A systematic characterization of the resulting system as a function of the initial concentrations was performed. The combination of UV-vis absorption - and its quantitative analysis - with X-ray photoelectron spectra, light scattering measurements and atomic force microscopy allowed obtaining a rational picture of silver reduction mechanism through the identification of the nature of the formed reduced/oxidized species. Nanoparticle mean sizes and sizes distributions were rather independent from the precursors initial absolute and relative concentrations ([AgNO 3 ]/[chitosan]). This work clarifies some points of the mechanism involved showing experimental evidence of the early stages of the very fast silver reduction in chitosan aqueous solutions through the spectral signature of the smallest silver aggregate (Ag 2 + ) even at room temperature. The characterized system is believed to be useful for research fields where silver nanoparticles completely exempt of harmful traces of inorganic ions, coming from additional reducing agents, are needed, especially to be used in biocompatible in films. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Nanoscale characterization and local piezoelectric properties of lead-free KNN-LT-LS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Abazari, M; Safari, A [Glenn Howatt Electroceramics Laboratories, Department of Materials Science and Engineering, Rutgers-The state University of New Jersey, Piscataway, NJ 08854 (United States); Choi, T; Cheong, S-W [Rutgers Center for Emergent Materials, Department of Physics and Astronomy, Rutgers-The state University of New Jersey, Piscataway, NJ 08854 (United States)

    2010-01-20

    We report the observation of domain structure and piezoelectric properties of pure and Mn-doped (K{sub 0.44},Na{sub 0.52},Li{sub 0.04})(Nb{sub 0.84},Ta{sub 0.1},Sb{sub 0.06})O{sub 3} (KNN-LT-LS) thin films on SrTiO{sub 3} substrates. It is revealed that, using piezoresponse force microscopy, ferroelectric domain structure in such 500 nm thin films comprised of primarily 180{sup 0} domains. This was in accordance with the tetragonal structure of the films, confirmed by relative permittivity measurements and x-ray diffraction patterns. Effective piezoelectric coefficient (d{sub 33}) of the films were calculated using piezoelectric displacement curves and shown to be {approx}53 pm V{sup -1} for pure KNN-LT-LS thin films. This value is among the highest values reported for an epitaxial lead-free thin film and shows a great potential for KNN-LT-LS to serve as an alternative to PZT thin films in future applications.

  12. Nanoscale characterization and local piezoelectric properties of lead-free KNN-LT-LS thin films

    Science.gov (United States)

    Abazari, M.; Choi, T.; Cheong, S.-W.; Safari, A.

    2010-01-01

    We report the observation of domain structure and piezoelectric properties of pure and Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.1,Sb0.06)O3 (KNN-LT-LS) thin films on SrTiO3 substrates. It is revealed that, using piezoresponse force microscopy, ferroelectric domain structure in such 500 nm thin films comprised of primarily 180° domains. This was in accordance with the tetragonal structure of the films, confirmed by relative permittivity measurements and x-ray diffraction patterns. Effective piezoelectric coefficient (d33) of the films were calculated using piezoelectric displacement curves and shown to be ~53 pm V-1 for pure KNN-LT-LS thin films. This value is among the highest values reported for an epitaxial lead-free thin film and shows a great potential for KNN-LT-LS to serve as an alternative to PZT thin films in future applications.

  13. Rough Electrode Creates Excess Capacitance in Thin-Film Capacitors.

    Science.gov (United States)

    Torabi, Solmaz; Cherry, Megan; Duijnstee, Elisabeth A; Le Corre, Vincent M; Qiu, Li; Hummelen, Jan C; Palasantzas, George; Koster, L Jan Anton

    2017-08-16

    The parallel-plate capacitor equation is widely used in contemporary material research for nanoscale applications and nanoelectronics. To apply this equation, flat and smooth electrodes are assumed for a capacitor. This essential assumption is often violated for thin-film capacitors because the formation of nanoscale roughness at the electrode interface is very probable for thin films grown via common deposition methods. In this work, we experimentally and theoretically show that the electrical capacitance of thin-film capacitors with realistic interface roughness is significantly larger than the value predicted by the parallel-plate capacitor equation. The degree of the deviation depends on the strength of the roughness, which is described by three roughness parameters for a self-affine fractal surface. By applying an extended parallel-plate capacitor equation that includes the roughness parameters of the electrode, we are able to calculate the excess capacitance of the electrode with weak roughness. Moreover, we introduce the roughness parameter limits for which the simple parallel-plate capacitor equation is sufficiently accurate for capacitors with one rough electrode. Our results imply that the interface roughness beyond the proposed limits cannot be dismissed unless the independence of the capacitance from the interface roughness is experimentally demonstrated. The practical protocols suggested in our work for the reliable use of the parallel-plate capacitor equation can be applied as general guidelines in various fields of interest.

  14. Friction laws at the nanoscale.

    Science.gov (United States)

    Mo, Yifei; Turner, Kevin T; Szlufarska, Izabela

    2009-02-26

    Macroscopic laws of friction do not generally apply to nanoscale contacts. Although continuum mechanics models have been predicted to break down at the nanoscale, they continue to be applied for lack of a better theory. An understanding of how friction force depends on applied load and contact area at these scales is essential for the design of miniaturized devices with optimal mechanical performance. Here we use large-scale molecular dynamics simulations with realistic force fields to establish friction laws in dry nanoscale contacts. We show that friction force depends linearly on the number of atoms that chemically interact across the contact. By defining the contact area as being proportional to this number of interacting atoms, we show that the macroscopically observed linear relationship between friction force and contact area can be extended to the nanoscale. Our model predicts that as the adhesion between the contacting surfaces is reduced, a transition takes place from nonlinear to linear dependence of friction force on load. This transition is consistent with the results of several nanoscale friction experiments. We demonstrate that the breakdown of continuum mechanics can be understood as a result of the rough (multi-asperity) nature of the contact, and show that roughness theories of friction can be applied at the nanoscale.

  15. Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity

    Energy Technology Data Exchange (ETDEWEB)

    Das, Saikat [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy; Wang, Bo [Pennsylvania State Univ., University Park, PA (United States).Dept. of Materials Science and Engineering; Cao, Ye [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Inst. for; Rae Cho, Myung [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy; Jae Shin, Yeong [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy; Mo Yang, Sang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Sookmyung Women' s Univ., Seoul (Republic of Korea). Dept. of Physics; Wang, Lingfei [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy; Kim, Minu [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy; Kalinin, Sergei V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Inst. for Functional Imaging of Materials; Chen, Long-Qing [Pennsylvania State Univ., University Park, PA (United States).Dept. of Materials Science and Engineering; Noh, Tae Won [Inst. for Basic Science (IBS), Seoul (Republic of Korea). Center for Correlated Electron Systems; Seoul National University (SNU), Seoul (Republic of Korea). Dept. of Physics and Astronomy

    2017-09-20

    Oxygen vacancies, especially their distribution, are directly coupled to the electromagnetic properties of oxides and related emergent functionalities that have implications for device applications. Here using a homoepitaxial strontium titanate thin film, we demonstrate a controlled manipulation of the oxygen vacancy distribution using the mechanical force from a scanning probe microscope tip. By combining Kelvin probe force microscopy imaging and phase-field simulations, we show that oxygen vacancies can move under a stress-gradient-induced depolarisation field. When tailored, this nanoscale flexoelectric effect enables a controlled spatial modulation. In motion, the scanning probe tip thereby deterministically reconfigures the spatial distribution of vacancies. Finally, the ability to locally manipulate oxygen vacancies on-demand provides a tool for the exploration of mesoscale quantum phenomena and engineering multifunctional oxide devices.

  16. Nanoscale decomposition of Nb-Ru-O

    Science.gov (United States)

    Music, Denis; Geyer, Richard W.; Chen, Yen-Ting

    2016-11-01

    A correlative theoretical and experimental methodology has been employed to explore the decomposition of amorphous Nb-Ru-O at elevated temperatures. Density functional theory based molecular dynamics simulations reveal that amorphous Nb-Ru-O is structurally modified within 10 ps at 800 K giving rise to an increase in the planar metal - oxygen and metal - metal population and hence formation of large clusters, which signifies atomic segregation. The driving force for this atomic segregation process is 0.5 eV/atom. This is validated by diffraction experiments and transmission electron microscopy of sputter-synthesized Nb-Ru-O thin films. Room temperature samples are amorphous, while at 800 K nanoscale rutile RuO2 grains, self-organized in an amorphous Nb-O matrix, are observed, which is consistent with our theoretical predictions. This amorphous/crystalline interplay may be of importance for next generation of thermoelectric devices.

  17. Measurement of Auger electron energies and intensities from muonic transitions in silver

    International Nuclear Information System (INIS)

    Callies, R.; Daniel, H.; Egidy, T. von; Hagn, H.; Hartmann, F.J.; Neumann, W.

    1983-01-01

    There is now general agreement that Coulomb capture of mesonic particles and deexcitation of the formed exotic atom must be accompanied by Auger electron emission. Auger electrons from a thin silver foil were counted by Si-pn-junction detectors with an extraordinarily thin dead layer. Lines could be resolved and intensity ratios determined. Two types of experiments were performed simultaneously, (I) with the slow-muon telescope in coincidence with any e - detector of the array and (II) as above but with an additional Ag X-ray coincidence from a Ge(Li) detector placed close to the target. (Auth.)

  18. Room temperature ferroelectricity in continuous croconic acid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xuanyuan; Lu, Haidong; Yin, Yuewei; Ahmadi, Zahra; Costa, Paulo S. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Zhang, Xiaozhe [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Department of Physics, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, Xiao; Yu, Le; Cheng, Xuemei [Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010 (United States); DiChiara, Anthony D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Gruverman, Alexei, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Enders, Axel, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Xu, Xiaoshan, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States)

    2016-09-05

    Ferroelectricity at room temperature has been demonstrated in nanometer-thin quasi 2D croconic acid thin films, by the polarization hysteresis loop measurements in macroscopic capacitor geometry, along with observation and manipulation of the nanoscale domain structure by piezoresponse force microscopy. The fabrication of continuous thin films of the hydrogen-bonded croconic acid was achieved by the suppression of the thermal decomposition using low evaporation temperatures in high vacuum, combined with growth conditions far from thermal equilibrium. For nominal coverages ≥20 nm, quasi 2D and polycrystalline films, with an average grain size of 50–100 nm and 3.5 nm roughness, can be obtained. Spontaneous ferroelectric domain structures of the thin films have been observed and appear to correlate with the grain patterns. The application of this solvent-free growth protocol may be a key to the development of flexible organic ferroelectric thin films for electronic applications.

  19. Fabrication, characterization and some applications of graded chiral zigzag shaped nano-sculptured silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Esfandiar, Ali [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of)

    2011-09-01

    Graded chiral zig-zag shaped nano-sculptured silver thin films (GCZSSTF) were produced in two stages using oblique deposition technique together with rotation of substrate about its surface normal while a shadowing block was also fixed at Center of the substrate holder. Chrystallographic and morphological structure of these films were obtained using X-ray diffraction (XRD) and atomic force microscopy (AFM). Spectrophotometry was used to obtain their optical behavior while their application in both hydrophobicity and gas sensing was also investigated. XRD results showed a dominant (1 1 1) orientation growth on the zig arm of the structure while by addition of the second arm (zag) the crystallographical growth orientation changed to (2 2 0). The anisotropic nano-structure of these films was also distinguished through (1 - R) spectra. A common peak at about 350 nm related to the TM mode of plasmon resonances and a broad shoulder at about 420 nm for the s-polarized light and at 620 nm for the p-polarized light corresponding to the LM mode of plasmon resonances are observed. These peaks are directly related to the nano-columns topography. The film system used here proved to act as a physical method for producing layer-by-layer structure for obtaining enhanced hydrophobic surfaces rather than the usual chemical methods reported in the literature. In addition, the GCZSSTF also acted as good as reported results for nano-tubes when applied as cathode in the field ionization gas sensing setup.

  20. Molecular dynamics study on evaporation and condensation characteristics of thin film liquid Argon on nanostructured surface in nano-scale confinement

    Science.gov (United States)

    Hasan, Mohammad Nasim; Rabbi, Kazi Fazle; Sabah, Arefiny; Ahmed, Jannat; Kuri, Subrata Kumar; Rakibuzzaman, S. M.

    2017-06-01

    Investigation of Molecular level phase change phenomena are becoming important in heat and mass transfer research at a very high rate, driven both by the need to understand certain fundamental phenomena as well as by a plethora of new and forthcoming applications in the areas of micro- and nanotechnologies. Molecular dynamics simulation has been carried out to go through the evaporation and condensation characteristics of thin liquid argon film in Nano-scale confinement. In the present study, a cuboid system is modeled for understanding the Nano-scale physics of simultaneous evaporation and condensation. The cuboid system consists of hot and cold parallel platinum plates at the bottom and top ends. The fluid comprised of liquid argon film at the bottom plate and vapor argon in between liquid argon and upper plate of the domain. Three different simulation domains have been created here: (i) Both platinum plates are considered flat, (ii) Upper plate consisting of transverse slots of low height and (iii) Upper plate consisting of transverse slots of bigger height. Considering hydrophilic nature of top and bottom plates, two different high temperatures of the hot wall was set and an observation was made on normal and explosive vaporizations and their impacts on thermal transport. For all the structures, equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. Then the lower wall is set to two different temperatures like 110 K and 250 K for all three models to perform non-equilibrium molecular dynamics (NEMD). For vaporization, higher temperature of the hot wall led to faster transport of the liquid argon as a cluster moving from hot wall to cold wall. But excessive temperature causes explosive boiling which seems not good for heat transportation because of less phase change. In case of condensation, an observation was made which indicates that the nanostructured transverse slots facilitate condensation. Two factors affect the rate of

  1. Nanoscale measurement of Nernst effect in two-dimensional charge density wave material 1T-TaS2

    Science.gov (United States)

    Wu, Stephen M.; Luican-Mayer, Adina; Bhattacharya, Anand

    2017-11-01

    Advances in nanoscale material characterization on two-dimensional van der Waals layered materials primarily involve their optical and electronic properties. The thermal properties of these materials are harder to access due to the difficulty of thermal measurements at the nanoscale. In this work, we create a nanoscale magnetothermal device platform to access the basic out-of-plane magnetothermal transport properties of ultrathin van der Waals materials. Specifically, the Nernst effect in the charge density wave transition metal dichalcogenide 1T-TaS2 is examined on nano-thin flakes in a patterned device structure. It is revealed that near the commensurate charge density wave (CCDW) to nearly commensurate charge density wave (NCCDW) phase transition, the polarity of the Nernst effect changes. Since the Nernst effect is especially sensitive to changes in the Fermi surface, this suggests that large changes are occurring in the out-of-plane electronic structure of 1T-TaS2, which are otherwise unresolved in just in-plane electronic transport measurements. This may signal a coherent evolution of out-of-plane stacking in the CCDW → NCCDW transition.

  2. Auger-electron spectroscopy investigation of thin Ag-As-S-Se films

    International Nuclear Information System (INIS)

    Todorov, R; Spasov, G; Petkov, K; Tasseva, J

    2010-01-01

    The photoinduced changes in the refractive index and optical band-gap of thin As 32 S 34 Se 34 films photodoped with silver were studied using spectrophotometric methods. The compositional profile of the films was revealed by means of Auger-electron spectroscopy.

  3. Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures

    International Nuclear Information System (INIS)

    Chen Yong; Cai Jiye; Zhao Tao; Wang Chenxi; Dong Shuo; Luo Shuqian; Chen, Zheng W.

    2005-01-01

    The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60 nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale

  4. Preliminary experiments using light-initiated high explosive for driving thin flyer plates

    International Nuclear Information System (INIS)

    Benham, R.A.

    1980-02-01

    Light-initiated high explosive, silver acelytide - silver-nitrate (SASN), has been used to produce simulated x ray blow-off impulse loading on reentry vehicles to study the system structural response. SASN can be used to accelerate thin flyer plates to high terminal velocities which, in turn, can deliver a pressure pulse that can be tailored to the target material. This process is important for impulse tests where both structural and material response is desired. The theories used to calculate the dynamic state of the flyer plate prior to impact are summarized. Data from several experiments are presented which indicate that thin flyer plates can be properly accelerated and that there are predictive techniques available which are adequate to calculate the motion of the flyer plate. Recommendations are made for future study that must be undertaken to make the SASN flyer plate technique usable

  5. Thin metal electrodes for semitransparent organic photovoltaics

    KAUST Repository

    Lee, Kyusung

    2013-08-01

    We demonstrate semitransparent organic photovoltaics (OPVs) based on thin metal electrodes and polymer photoactive layers consisting of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester. The power conversion efficiency of a semitransparent OPV device comprising a 15-nm silver (Ag) rear electrode is 1.98% under AM 1.5-G illumination through the indium-tin-oxide side of the front anode at 100 mW/cm2 with 15.6% average transmittance of the entire cell in the visible wavelength range. As its thickness increases, a thin Ag electrode mainly influences the enhancement of the short circuit current density and fill factor. Its relatively low absorption intensity makes a Ag thin film a viable option for semitransparent electrodes compatible with organic layers. © 2013 ETRI.

  6. Silver nanoparticle ink technology: state of the art

    Directory of Open Access Journals (Sweden)

    Rajan K

    2016-01-01

    Full Text Available Krishna Rajan, Ignazio Roppolo, Annalisa Chiappone, Sergio Bocchini, Denis Perrone, Alessandro Chiolerio Center for Space Human Robotics, Italian Institute of Technology, Turin, Italy Abstract: Printed electronics will bring to the consumer level great breakthroughs and unique products in the near future, shifting the usual paradigm of electronic devices and circuit boards from hard boxes and rigid sheets into flexible thin layers and bringing disposable electronics, smart tags, and so on. The most promising tool to achieve the target depends upon the availability of nanotechnology-based functional inks. A certain delay in the innovation-transfer process to the market is now being observed. Nevertheless, the most widely diffused product, settled technology, and the highest sales volumes are related to the silver nanoparticle-based ink market, representing the best example of commercial nanotechnology today. This is a compact review on synthesis routes, main properties, and practical applications. Keywords: silver nanoparticles, surface plasmon resonance, nanocomposites, inks, printed electronics

  7. Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

    Institute of Scientific and Technical Information of China (English)

    Sirikamon Saengmee-anupharb; Toemsak Srikhirin; Boonyanit Thaweboon; Sroisiri Thaweboon; Taweechai Amornsakchai; Surachai Dechkunakorn; Theeralaksna Suddhasthira

    2013-01-01

    Objective: To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods: The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candidaalbicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results: All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5-3.0 µm) and more uniformly shaped than AgZ. Conclusions: Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

  8. Antimicrobial effects of silver zeolite,silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

    Institute of Scientific and Technical Information of China (English)

    Sirikamon; Saengmee-anupharb; Toemsak; Srikhirin; Boonyanit; Thaweboon; Sroisiri; Thaweboon; Taweechai; Amornsakchai; Surachai; Dechkunakorn; Theeralaksna; Suddhasthira

    2013-01-01

    Objective:To evaluate the antimicrobial activities of silver inorganic materials,including silver zeolite(AgZ),silver zirconium phosphate silicate(AgZrPSi)and silver zirconium phosphate(AgZrp),against oral microorganisms.In line with this objective,the morphology and structure of each type of silver based powders were also investigated.Methods:The antimicrobial activities of AgZ,AgZrPSi and AgZrP were tested against Streptococcus mutans,Lactobacillus casei,Candida albicans and Staphylococcus aureus using disk diffusion assay as a screening test.The minimum inhibitory concentration(MIC)and minimum lethal concentration(MLC)were determined using the modified membrane method.Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials.Results:All forms of silver inorganic materials could inhibit the growth of all test microorganisms.The MIC of AgZ,AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L.In terms of morphology and structure.AgZrPSi and AgZrP had smaller sized particles(1.5-3.0μm)and more uniformly shaped than AgZ.Conclusions:Silver inorganic materials in the form of AgZ,AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers.These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

  9. Physical properties and characterization of Ag doped CdS thin films

    International Nuclear Information System (INIS)

    Shah, N.A.; Nazir, A.; Mahmood, W.; Syed, W.A.A.; Butt, S.; Ali, Z.; Maqsood, A.

    2012-01-01

    Highlights: ► CdS thin films were grown. ► By ion exchange, Ag was doped. ► Physical properties were investigated. - Abstract: Thin films of cadmium sulfide with very well defined preferential orientation and relatively high absorption coefficient were fabricated by thermal evaporation technique. The research is focused to the fabrication and characterization of the compositional data of CdS thin films obtained by using X-ray diffraction, scanning electron microscope along with energy dispersive X-ray spectroscopy. The optical properties were studied by using a UV-VIS-NIR spectrophotometer. The effects of silver-doping by ion exchange process on the properties of as-deposited CdS thin films have been investigated.

  10. Nanoscale-Barrier Formation Induced by Low-Dose Electron-Beam Exposure in Ultrathin MoS2 Transistors.

    Science.gov (United States)

    Matsunaga, Masahiro; Higuchi, Ayaka; He, Guanchen; Yamada, Tetsushi; Krüger, Peter; Ochiai, Yuichi; Gong, Yongji; Vajtai, Robert; Ajayan, Pulickel M; Bird, Jonathan P; Aoki, Nobuyuki

    2016-10-05

    Utilizing an innovative combination of scanning-probe and spectroscopic techniques, supported by first-principles calculations, we demonstrate how electron-beam exposure of field-effect transistors, implemented from ultrathin molybdenum disulfide (MoS 2 ), may cause nanoscale structural modifications that in turn significantly modify the electrical operation of these devices. Quite surprisingly, these modifications are induced by even the relatively low electron doses used in conventional electron-beam lithography, which are found to induce compressive strain in the atomically thin MoS 2 . Likely arising from sulfur-vacancy formation in the exposed regions, the strain gives rise to a local widening of the MoS 2 bandgap, an idea that is supported both by our experiment and by the results of first-principles calculations. A nanoscale potential barrier develops at the boundary between exposed and unexposed regions and may cause extrinsic variations in the resulting electrical characteristics exhibited by the transistor. The widespread use of electron-beam lithography in nanofabrication implies that the presence of such strain must be carefully considered when seeking to harness the potential of atomically thin transistors. At the same time, this work also promises the possibility of exploiting the strain as a means to achieve "bandstructure engineering" in such devices.

  11. Low-temperature preparation of rutile-type TiO2 thin films for optical coatings by aluminum doping

    Science.gov (United States)

    Ishii, Akihiro; Kobayashi, Kosei; Oikawa, Itaru; Kamegawa, Atsunori; Imura, Masaaki; Kanai, Toshimasa; Takamura, Hitoshi

    2017-08-01

    A rutile-type TiO2 thin film with a high refractive index (n), a low extinction coefficient (k) and small surface roughness (Ra) is required for use in a variety of optical coatings to improve the controllability of the reflection spectrum. In this study, Al-doped TiO2 thin films were prepared by pulsed laser deposition, and the effects of Al doping on their phases, optical properties, surface roughness and nanoscale microstructure, including Al distribution, were investigated. By doping 5 and 10 mol%Al, rutile-type TiO2 was successfully prepared under a PO2 of 0.5 Pa at 350-600 °C. The nanoscale phase separation in the Al-doped TiO2 thin films plays an important role in the formation of the rutile phase. The 10 mol%Al-doped rutile-type TiO2 thin film deposited at 350 °C showed excellent optical properties of n ≈ 3.05, k ≈ 0.01 (at λ = 400 nm) and negligible surface roughness, at Ra ≈ 0.8 nm. The advantages of the superior optical properties and small surface roughness of the 10 mol%Al-doped TiO2 thin film were confirmed by fabricating a ten-layered dielectric mirror.

  12. Overcoming the limitations of silver nanowire electrodes for light emitting applications

    Science.gov (United States)

    Chen, Dustin Yuan

    The global lighting market is projected to exceed 100 billion dollars by 2020, undergoing rapid transitions driven by technological advancements. In conjunction with increased demand for new technology, global regulations have become increasingly stringent, mandating the development and implementation of more fuel-efficient light sources. As prior generations of lighting technology such as incandescent bulbs and florescent lighting progressively become phased out, newer technologies such as light emitting diodes (LEDs) and organic light emitting diodes (OLEDs) have become progressively popular and commonplace. Though they still lag behind LEDs in terms of market penetration, OLEDs have garnered increasing amounts of attention in recent years due to unique attributes such as their exotic and large scale form factors, mechanical flexibility, and potential for high volume, low-cost manufacturing. Unfortunately, the costs for OLED manufacturing are currently still prohibitively high for several applications, with the anode and substrate representing 20-25 percent of this total cost. Significant technical and processing improvements for OLED substrates are of utmost necessity for fiscal cost reduction and commercialization of OLED technology. Silver nanowires have gained traction as a potential replacement for the current status quo, indium tin oxide (ITO) due to attributes such as flexibility, low cost processing, and high optoelectronic properties. However, due to nanoscale size effects, the integration of silver nanowires in both process flows and operational use has proven to be problematic. This work makes several key contributions towards enabling the use of silver nanowires for practical and commercial applications within the lighting industry. First, a novel method for the fabrication of a high temperature-stable, flexible substrate with surface roughness (Ra) traditional process flows, and validity for use in extreme processing conditions. Secondly, the

  13. Analysis of polymer surfaces and thin-film coatings with Raman and surface enhanced Raman scattering

    International Nuclear Information System (INIS)

    McAnally, Gerard David

    2001-01-01

    This thesis investigates the potential of surface-enhanced Raman scattering (SERS) for the analysis and characterisation of polymer surfaces. The Raman and SERS spectra from a PET film are presented. The SERS spectra from the related polyester PBT and from the monomer DMT are identical to PET, showing that only the aromatic signals are enhanced. Evidence from other compounds is presented to show that loss of the carbonyl stretch (1725 cm -1 ) from the spectra is due to a chemical interaction between the silver and surface carbonyl groups. The interaction of other polymer functional groups with silver is discussed. A comparison of Raman and SERS spectra collected from three faces of a single crystal shows the SERS spectra are depolarised. AFM images of the silver films used to obtain SERS are presented. They consist of regular islands of silver, fused together to form a complete film. The stability and reproducibility and of these surfaces is assessed. Band assignments for the SERS spectrum of PET are presented. A new band in the spectrum (1131 cm -1 ) is assigned to a complex vibration using a density functional calculation. Depth profiling through a polymer film on to the silver layer showed the SERS signals arise from the silver surface only. The profiles show the effects of refraction on the beam, and the adverse affect on the depth resolution. Silver films were used to obtain SERS spectra from a 40 nm thin-film coating on PET, without interference from the PET layer. The use of an azo dye probe as a marker to detect the coating is described. Finally, a novel method for the synthesis of a SERS-active vinyl-benzotriazole monomer is reported. The monomer was incorporated into a thin-film coating and the SERS spectrum obtained from the polymer. (author)

  14. Dependence of Optical Properties of SEL-Deposited Silver Gallium Selenide Thin Films on the On-Line Growth Parameter: Annealing Duration

    International Nuclear Information System (INIS)

    Bhuiyan, M.R.A.; Firoz Hasan, S.M.

    2005-01-01

    Silver gallium selenide (AGS) composite thin films were formed onto ultrasonically and chemically cleaned glass substrates by successive on-line thermal evaporation of individual elements and post-deposition annealing at 300 0 C for various durations in vacuum. The annealing duration was varied between 5 and 20 minutes. The structural and optical properties of the films were ascertained by x-ray diffraction (XRD) and uv-vis-nir spectrophotometry (photon wavelength ranging between 300 and 2500 nm), respectively. The diffractogram indicated that these films were polycrystalline in nature having tetragonal structure with lattice parameters, a ∼ 6.0034 A and c ∼ 10.9165 A. The optical transmittance and reflectance were utilized to compute the absorption coefficient, refractive index and energy gap of the films. Dependence of the optical and structural properties of the films on various annealing durations has been analyzed. The nature of the optical transitions has been direct allowed with band gap energies ranging between 1.713 and 1.757 eV and refractive indices between 1.596 and 3.351 depending on photon energy as well as annealing duration. (authors)

  15. Auger-electron spectroscopy investigation of thin Ag-As-S-Se films

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, R; Spasov, G; Petkov, K; Tasseva, J, E-mail: jordanka@clf.bas.b [Acad. J. Malinowski Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 1113 Sofia (Bulgaria)

    2010-04-01

    The photoinduced changes in the refractive index and optical band-gap of thin As{sub 32}S{sub 34}Se{sub 34} films photodoped with silver were studied using spectrophotometric methods. The compositional profile of the films was revealed by means of Auger-electron spectroscopy.

  16. Structurally Stable Attractive Nanoscale Emulsions with Dipole-Dipole Interaction-Driven Interdrop Percolation.

    Science.gov (United States)

    Shin, Kyounghee; Gong, Gyeonghyeon; Cuadrado, Jonas; Jeon, Serim; Seo, Mintae; Choi, Hong Sung; Hwang, Jae Sung; Lee, Youngbok; Fernandez-Nieves, Alberto; Kim, Jin Woong

    2017-03-28

    This study introduces an extremely stable attractive nanoscale emulsion fluid, in which the amphiphilic block copolymer, poly(ethylene oxide)-block-poly(ϵ-caprolactone) (PEO-b-PCL), is tightly packed with lecithin, thereby forming a mechanically robust thin-film at the oil-water interface. The molecular association of PEO-b-PCL with lecithin is critical for formation of a tighter and denser molecular assembly at the interface, which is systematically confirmed by T 2 relaxation and DSC analyses. Moreover, suspension rheology studies also reflect the interdroplet attractions over a wide volume fraction range of the dispersed oil phase; this results in a percolated network of stable drops that exhibit no signs of coalescence or phase separation. This unique rheological behavior is attributed to the dipolar interaction between the phosphorylcholine groups of lecithin and the methoxy end groups of PEO-b-PCL. Finally, the nanoemulsion system significantly enhances transdermal delivery efficiency due to its favorable attraction to the skin, as well as high diffusivity of the nanoscale emulsion drops. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Epitaxial growth of textured YBa2Cu3O7-δ films on silver

    International Nuclear Information System (INIS)

    Liu Dan-Min; Liu Wei-Peng; Suo Hong-Li; Zhou Mei-Ling

    2005-01-01

    YBa 2 Cu 3 O 7-δ (YBCO) films were deposited on (100), (110) and (111) oriented silver single crystals and {100} left angle 100 right angle, {110} left angle 211 right angle, {110} left angle 100 right angle +{110} left angle 011 right angle {110} left angle 011 right angle and {012} left angle 100 right angle textured Ag substrates using pulsed laser deposition. The relationship between the epitaxial growth YBCO film and silver substrate has been determined. It is shown that among polycrystalline Ag substrates, {110} left angle 011 right angle textured tape is suitable for the deposition of YBCO thin films having strong texture. (orig.)

  18. A review of silver-rich mineral deposits and their metallogeny

    Science.gov (United States)

    Graybeal, Frederick T.; Vikre, Peter

    2010-01-01

    Mineral deposits with large inventories or high grades of silver are found in four genetic groups: (1) volcanogenic massive sulfide (VMS), (2) sedimentary exhalative (SEDEX), (3) lithogene, and, (4) magmatichydrothermal. Principal differences between the four groups relate to source rocks and regions, metal associations, process and timing of mineralization, and tectonic setting. These four groups may be subdivided into specific metal associations on ternary diagrams based on relative metal contents. The VMS deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 33 g/t Ag. Variable Ag- Pb-Zn-Cu-Au ± Sn concentrations are interpreted as having been derived both from shallow plutons and by leaching of the volcanic rock pile in regions of thin or no continental crust and the mineralization is syngenetic. Higher silver grades are associated with areas of abundant felsic volcanic rocks. The SEDEX deposits rarely contain more than 15,600 t Ag (500 Moz). Grades average 46 g/t Ag. Silver, lead, and zinc in relatively consistent proportions are leached from sedimentary rocks filling rift-related basins, where the continental crust is thin, and deposited as syngenetic to diagenetic massive sulfides. Pre-mineral volcanic rocks and their detritus may occur deep within the basin and gold is typically absent. Lithogene silver-rich deposits are epigenetic products of varying combinations of compaction, dewatering, meteoric water recharge, and metamorphism of rift basin-related clastic sedimentary and interbedded volcanic rocks. Individual deposits may contain more than 15,600 t Ag (500 Moz) at high grades. Ores are characterized by four well-defined metal associations, including Ag, Ag-Pb-Zn, Ag-Cu, and Ag-Co-Ni-U. Leaching, transport, and deposition of metals may occur both in specific sedimentary strata and other rock types adjacent to the rift. Multiple mineralizing events lasting 10 to 15 m.y., separated by as much as 1 b.y., may occur in a single basin

  19. Partitioned airs at microscale and nanoscale: thermal diffusivity in ultrahigh porosity solids of nanocellulose

    Science.gov (United States)

    Sakai, Koh; Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

    2016-02-01

    High porosity solids, such as plastic foams and aerogels, are thermally insulating. Their insulation performance strongly depends on their pore structure, which dictates the heat transfer process in the material. Understanding such a relationship is essential to realizing highly efficient thermal insulators. Herein, we compare the heat transfer properties of foams and aerogels that have very high porosities (97.3-99.7%) and an identical composition (nanocellulose). The foams feature rather closed, microscale pores formed with a thin film-like solid phase, whereas the aerogels feature nanoscale open pores formed with a nanofibrous network-like solid skeleton. Unlike the aerogel samples, the thermal diffusivity of the foam decreases considerably with a slight increase in the solid fraction. The results indicate that for suppressing the thermal diffusion of air within high porosity solids, creating microscale spaces with distinct partitions is more effective than directly blocking the free path of air molecules at the nanoscale.

  20. The spectroscopy and dosimetry of silver-L radiation for biophysical applications

    International Nuclear Information System (INIS)

    Modler, H.

    1984-01-01

    In order to carry out biological radiation experiments with low energy electrons, whose limited range as a rule even for single cell layers is not sufficient to pass through the cytoplasm to the nucleus, one must work with low energy X-rays. The electrons which are released directly in the cell by the photo effect are then the biologically active, directly ionized particles, whose starting spectrum can be determined by the selection of the photon spectra. The problem was to build an apparatus for irradiation of thin cell layers with low energy X-rays, which contained a large portion of the silver-L lines at approximately 3 keV, as well as to carry out the necessary spectrometry and dosimetry with the silver anode tubes and to optimize the irradiation parameters. (orig./PW) [de

  1. Electrically Conductive Silver Paste Obtained by Use of Silver Neodecanoate as Precursor

    Science.gov (United States)

    Shen, Longguang; Liu, Jianguo; Zeng, Xiaoyan; Ren, Zhao

    2015-02-01

    An electrically conductive silver paste has been prepared from an organometallic compound, silver neodecanoate, as silver precursor. The precursor was highly soluble in organic solvents and decomposed into metallic silver at low sintering temperatures (writing process, enabling production of silver lines on a substrate. The electrical resistivity of the silver lines was 9 × 10-6 Ω cm after sintering at 115°C for 60 min, 5.8 × 10-6 Ω cm when sintered at 150°C for 60 min, and 3 × 10-6 Ω cm when sintered above 300°C, values which are similar to those of bulk silver. Hence, the prepared paste can be successfully used on flexible substrates such as polymers.

  2. Size dependence of the optical spectrum in nanocrystalline silver

    International Nuclear Information System (INIS)

    Taneja, Praveen; Ayyub, Pushan; Chandra, Ramesh

    2002-01-01

    We report a detailed study of the optical reflectance in sputter-deposited, nanocrystalline silver thin films in order to understand the marked changes in color that occur with decreasing particle size. In particular, samples with an average particle size in the 20 to 35 nm range are golden yellow, while those with a size smaller than 15 nm are black. We simulate the size dependence of the observed reflection spectra by incorporating Mie's theory of scattering and absorption of light in small particles, into the bulk dielectric constant formalism given by Ehrenreich and Philipp [Phys. Rev. 128, 1622 (1962)]. This provides a general method for understanding the reflected color of a dense collection of nanoparticles, such as in a nanocrystalline thin film. A deviation from Mie's theory is observed due to strong interparticle interactions

  3. Strain Imaging of Nanoscale Semiconductor Heterostructures with X-Ray Bragg Projection Ptychography

    Science.gov (United States)

    Holt, Martin V.; Hruszkewycz, Stephan O.; Murray, Conal E.; Holt, Judson R.; Paskiewicz, Deborah M.; Fuoss, Paul H.

    2014-04-01

    We report the imaging of nanoscale distributions of lattice strain and rotation in complementary components of lithographically engineered epitaxial thin film semiconductor heterostructures using synchrotron x-ray Bragg projection ptychography (BPP). We introduce a new analysis method that enables lattice rotation and out-of-plane strain to be determined independently from a single BPP phase reconstruction, and we apply it to two laterally adjacent, multiaxially stressed materials in a prototype channel device. These results quantitatively agree with mechanical modeling and demonstrate the ability of BPP to map out-of-plane lattice dilatation, a parameter critical to the performance of electronic materials.

  4. Leaching of Silver from Silver-Impregnated Food Storage Containers

    Science.gov (United States)

    Hauri, James F.; Niece, Brian K.

    2011-01-01

    The use of silver in commercial products has proliferated in recent years owing to its antibacterial properties. Food containers impregnated with micro-sized silver promise long food life, but there is some concern because silver can leach out of the plastic and into the stored food. This laboratory experiment gives students the opportunity to…

  5. Silver niobates

    International Nuclear Information System (INIS)

    Tanirbergenov, B.; Rozhenko, S.P.

    1979-01-01

    By means of determination of residual concentrations and pH measurements investigated are the AgNO 3 -KNbO 3 -H 2 O, AgNO 3 -K 3 NbO 4 -H 2 O, AgNO 3 -K 8 Nb 16 O 19 -H 2 O systems and established is formation of meta-, ortho-and hexaniobates of silver. AgNbO 3 x H 2 O, Ag 8 Nb 6 O 19 x 6H 2 O and Ag 3 NbO 3 x 2.5H 2 O are separated from aqueous solution. Using the methods of differential-thermal, thermogravimetric and X-ray-phase analyses it is shown that silver metaniobate transforms into the crystal state at 530 deg C. Ortho- and hexaniobate of silver decompose at 500 deg C with formation of silver metaniobate and metal silver

  6. Silver and copper nanoclusters in the lustre decoration of Italian Renaissance pottery: an EXAFS study

    Science.gov (United States)

    Padovani, S.; Borgia, I.; Brunetti, B.; Sgamellotti, A.; Giulivi, A.; D'Acapito, F.; Mazzoldi, P.; Sada, C.; Battaglin, G.

    Lustre is one of the most important decorative techniques of the Medieval and Renaissance pottery of the Mediterranean basin, capable of producing brilliant metallic reflections and iridescence. Following the recent finding that the colour of lustre decorations is mainly determined by copper and silver nanoclusters dispersed in the glaze layer, the local environment of copper and silver atoms has been studied by extended X-ray absorption fine structure (EXAFS) spectroscopy on original samples of gold and red lustre. It has been found that, in gold lustre, whose colour is attributed mainly to the silver nanocluster dispersion, silver is only partially present in the metallic form and copper is almost completely oxidised. In the red lustre, whose colour is attributed mainly to the copper nanocluster dispersion, only a fraction of copper is present in the metallic form. EXAFS measurements on red lustre, carried out in the total electron yield mode to probe only the first 150 nm of the glaze layer, indicated that in some cases lustre nanoclusters may be confined in a very thin layer close to the surface.

  7. Ion beam analysis and AMS dating of the silver coin hoard of Preuschdorf (Alsace, France)

    Science.gov (United States)

    Beck, Lucile; Alloin, Elise; Vigneron, Anaïs; Caffy, Ingrid; Klein, Ulrich

    2017-09-01

    The hoard of Preuschdorf is a monetary deposit discovered in Alsace (France) in 2005. This find was composed of 7327 silver-copper coins. They seem to have been struck over more than one century, between the end of the 15th and the beginning of the 17th century. This hoard is an exceptional find composed of a large quantity of coins from various periods, areas and contexts. It is also remarkable by the presence of counterfeit coins. IBA was used to analyze the silver content of the official coins by combining PIXE and RBS. The fineness was found to be between 20 and 42% according to the mint place and an unexpected subdivision of the values has been revealed. For the counterfeit coins, the analyses were able to bring to light different elaboration processes: amalgam silvering with two various contents of mercury and application of a thin layer of pure silver. Finally, linen fibers attached to the coins have been dated by AMS radiocarbon dating. The radiocarbon calibrated dates perfectly match with the chronological range given by the coins.

  8. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

    International Nuclear Information System (INIS)

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi

    2015-01-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO 3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi

  9. Reversible migration of silver on memorized pathways in Ag-Ge{sub 40}S{sub 60} films

    Energy Technology Data Exchange (ETDEWEB)

    Orava, J., E-mail: jo316@cam.ac.uk, E-mail: alg13@cam.ac.uk; Greer, A. L., E-mail: jo316@cam.ac.uk, E-mail: alg13@cam.ac.uk [Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kozicki, M. N. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-6206 (United States); Yannopoulos, S. N. [Foundation of Research and Technology Hellas - Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Patras, P. O. Box 1414 (Greece)

    2015-07-15

    Reversible and reproducible formation and dissolution of silver conductive filaments are studied in Ag-photodoped thin-film Ge{sub 40}S{sub 60} subjected to electric fields. A tip-planar geometry is employed, where a conductive-atomic-force microscopy tip is the tip electrode and a silver patch is the planar electrode. We highlight an inherent “memory” effect in the amorphous chalcogenide solid-state electrolyte, in which particular silver-ion migration pathways are preserved “memorized” during writing and erasing cycles. The “memorized” pathways reflect structural changes in the photodoped chalcogenide film. Structural changes due to silver photodoping, and electrically-induced structural changes arising from silver migration, are elucidated using Raman spectroscopy. Conductive filament formation, dissolution, and electron (reduction) efficiency in a lateral device geometry are related to operation of the nano-ionic Programmable Metallization Cell memory and to newly emerging chalcogenide-based lateral geometry MEMS technologies. The methods in this work can also be used for qualitative multi-parameter sampling of metal/amorphous-chalcogenide combinations, characterizing the growth/dissolution rates, retention and endurance of fractal conductive filaments, with the aim of optimizing devices.

  10. Confinement Effects on Host Chain Dynamics in Polymer Nanocomposite Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kyle J. [Department; Glynos, Emmanouil [Department; Maroulas, Serafeim-Dionysios [Department; Narayanan, Suresh [Advanced; Sakellariou, Georgios [Department; Green, Peter F. [Department; National

    2017-09-07

    Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g., sensing, energy conversion) of these materials influences other properties. One challenge is to understand the effects of nanoparticles on the viscosity of nanoscale thick polymer films. A new mechanism that contributes to an enhancement of the viscosity of nanoscale thick polymer/nanoparticle films is identified. We show that while the viscosities of neat homopolymer poly(2-vinylpyridine) (P2VP) films as thin as 50 nm remained the same as the bulk, polymer/nanoparticle films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibited unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were comparable to the bulk values. These results - NP proximities and suppression of their dynamics - suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for nanoscale applications.

  11. Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth.

    Science.gov (United States)

    Brower, Landon J; Gentry, Lauren K; Napier, Amanda L; Anderson, Mary E

    2017-01-01

    Integration of surface-anchored metal-organic frameworks (surMOFs) within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm) initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm) covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

  12. Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth

    Directory of Open Access Journals (Sweden)

    Landon J. Brower

    2017-11-01

    Full Text Available Integration of surface-anchored metal-organic frameworks (surMOFs within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

  13. Thin film soft X-ray absorption filters

    International Nuclear Information System (INIS)

    Stattin, H.

    1992-11-01

    This report discusses the composition, reparation and performance of soft x-ray transmission filters for a water window soft x-ray microscope. Unbacked thin films of aluminum, silver and vanadium/aluminum were made by evaporation on a substrate from which they were released. Measured transmittances agree reasonably well with calculations. The report also includes some related theory and discussions about film preparation methods, film contamination and evaluation methods. 33 refs

  14. Conformable Skin-Like Conductive Thin Films with AgNWs Strips for Flexible Electronic Devices

    Directory of Open Access Journals (Sweden)

    Yuhang SUN

    2015-08-01

    Full Text Available Keeping good conductivity at high stretching strain is one of the main requirements for the fabrication of flexible electronic devices. The elastic nature of siloxane-based elastomers enables many innovative designs in wearable sensor devices and non-invasive insertion instruments, including skin-like tactile sensors. Over the last few years, polydimethylsiloxane (PDMS thin films have been widely used as the substrates in the fabrication of flexible electronic devices due to their good elasticity and outstanding biocompatibility. However, these kind of thin films usually suffer poor resistance to tearing and insufficient compliance to curved surfaces, which limits their applications. Currently no three-dimensionally mountable tactile sensor arrays have been reported commercially available. In this work, we developed a kind of mechanically compliant skin-like conductive thin film by patterning silver nano wire traces in strip-style on Dragon Skin® (DS substrates instead of PDMS. High cross- link quality was achieved then. To further improve the conductivity, a thin gold layer was coated onto the silver nanowires (AgNWs strips. Four different gold deposition routines have been designed and investigated by using different E-beam and spin coating processing methods. Owning to the intrinsically outstanding physical property of the Dragon Skin material and the uniform embedment built in the gold deposition processes, the DS/AgNWs thin films showed convincible advantages over PDMS/AgNWs thin films in both mechanical capability and conductive stability. Through experimental tests, the DS/AgNWs electrode thin films were proven to be able to maintain high conductivity following repeated linear deformations.

  15. Nanoscale thermal transport

    Science.gov (United States)

    Cahill, David G.; Ford, Wayne K.; Goodson, Kenneth E.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Merlin, Roberto; Phillpot, Simon R.

    2003-01-01

    Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid-solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The

  16. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi, E-mail: yangdz@mail.buct.edu.cn

    2015-06-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO{sub 3} aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi.

  17. Development kinetics of silver clusters on silver halides

    International Nuclear Information System (INIS)

    Grzesiak, S.; Belloni, J.; Marignier, J.-L.

    2008-01-01

    Silver nuclei are produced by pulse radiolysis at the surface of AgCl nanocrystallites in the presence of an electron donor, the methyl viologen, which induces the growth of silver nuclei. The experimental results observed on the increase of the silver atom concentration and on the decay of the donor concentration during this process, which is similar to the photographic development by an electron donor, are compared with the kinetics obtained from numerical simulation. The model assumes that the formation of silver clusters with a supercritical nuclearity is required before the start of an electron transfer reaction from the two reduced forms of the donor methyl viologen to the silver clusters. The reaction is controlled by the access of the donor to the surface sites of the AgCl crystallite. The rate constant values of the successive steps of the mechanism are derived from the adjustment of calculated kinetics to experimental signals under various conditions, using a single set of parameters which are fairly suitable under all conditions studied

  18. Imaging Local Polarization in Ferroelectric Thin Films by Coherent X-Ray Bragg Projection Ptychography

    Science.gov (United States)

    Hruszkewycz, S. O.; Highland, M. J.; Holt, M. V.; Kim, Dongjin; Folkman, C. M.; Thompson, Carol; Tripathi, A.; Stephenson, G. B.; Hong, Seungbum; Fuoss, P. H.

    2013-04-01

    We used x-ray Bragg projection ptychography (BPP) to map spatial variations of ferroelectric polarization in thin film PbTiO3, which exhibited a striped nanoscale domain pattern on a high-miscut (001) SrTiO3 substrate. By converting the reconstructed BPP phase image to picometer-scale ionic displacements in the polar unit cell, a quantitative polarization map was made that was consistent with other characterization. The spatial resolution of 5.7 nm demonstrated here establishes BPP as an important tool for nanoscale ferroelectric domain imaging, especially in complex environments accessible with hard x rays.

  19. Russell-Silver syndrome

    Science.gov (United States)

    Silver-Russell syndrome; Silver syndrome; RSS; Russell-Silver syndrome ... One in 10 children with this syndrome has a problem involving chromosome 7. In other people with the syndrome, it may affect chromosome 11. Most of the time, it ...

  20. Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

    DEFF Research Database (Denmark)

    Löschner, Katrin; Hadrup, Niels; Qvortrup, Klaus

    2011-01-01

    Background: The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food...... and food contact materials. Results: AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer polyvinylpyrrolidone (PVP). The AgNPs remained stable throughout the duration of the 28-day oral toxicity study...... in rats. The organ distribution pattern of silver following administration of AgNPs and AgAc was similar. However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of Ag...

  1. Characterization of silver-gallium nanowires for force and mass sensing applications

    International Nuclear Information System (INIS)

    Biedermann, Laura B; Reifenberger, Ronald G; Tung, Ryan C; Raman, Arvind; Yazdanpanah, Mehdi M; Cohn, Robert W

    2010-01-01

    We investigate the mechanical properties of cantilevered silver-gallium (Ag 2 Ga) nanowires using laser Doppler vibrometry. From measurements of the resonant frequencies and associated operating deflection shapes, we demonstrate that these Ag 2 Ga nanowires behave as ideal Euler-Bernoulli beams. Furthermore, radial asymmetries in these nanowires are detected through high resolution measurements of the vibration spectra. These crystalline nanowires possess many ideal characteristics for nanoscale force and mass sensing, including small spring constants (as low as 10 -4 N m -1 ), high frequency bandwidth with resonance frequencies in the 0.02-10 MHz range, small suspended mass (picograms), and relatively high Q-factors (∼2-50) under ambient conditions. We evaluate the utility of Ag 2 Ga nanowires for nanocantilever applications, including ultrasmall mass and high frequency bandwidth piconewton force detection.

  2. Time-resolved analysis of thickness-dependent dewetting and ablation of silver films upon nanosecond laser irradiation

    International Nuclear Information System (INIS)

    Qi, Dongfeng; Paeng, Dongwoo; Yeo, Junyeob; Kim, Eunpa; Wang, Letian; Grigoropoulos, Costas P.; Chen, Songyan

    2016-01-01

    Nanosecond pulsed laser dewetting and ablation of thin silver films is investigated by time-resolved imaging. Laser pulses of 532 nm wavelength and 5 ns temporal width are irradiated on silver films of different thicknesses (50 nm, 80 nm, and 350 nm). Below the ablation threshold, it is observed that the dewetting process does not conclude until 630 ns after the laser irradiation for all samples, forming droplet-like particles in the spot central region. At higher laser intensities, ablative material removal occurs in the spot center. Cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter at about 700 ns following the laser pulse exposure. In addition to these features, droplet fingers are superposed upon irradiation of 350-nm thick silver films with higher intensity.

  3. Time-resolved analysis of thickness-dependent dewetting and ablation of silver films upon nanosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Dongfeng [Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720-1740 (United States); Semiconductor Photonics Research Center, Department of Physics, Xiamen University, Xiamen 361005 (China); Paeng, Dongwoo; Yeo, Junyeob; Kim, Eunpa; Wang, Letian; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720-1740 (United States); Chen, Songyan [Semiconductor Photonics Research Center, Department of Physics, Xiamen University, Xiamen 361005 (China)

    2016-05-23

    Nanosecond pulsed laser dewetting and ablation of thin silver films is investigated by time-resolved imaging. Laser pulses of 532 nm wavelength and 5 ns temporal width are irradiated on silver films of different thicknesses (50 nm, 80 nm, and 350 nm). Below the ablation threshold, it is observed that the dewetting process does not conclude until 630 ns after the laser irradiation for all samples, forming droplet-like particles in the spot central region. At higher laser intensities, ablative material removal occurs in the spot center. Cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter at about 700 ns following the laser pulse exposure. In addition to these features, droplet fingers are superposed upon irradiation of 350-nm thick silver films with higher intensity.

  4. Plasmonic 3D-structures based on silver decorated nanotips for biological sensing

    Science.gov (United States)

    Coluccio, M. L.; Francardi, M.; Gentile, F.; Candeloro, P.; Ferrara, L.; Perozziello, G.; Di Fabrizio, E.

    2016-01-01

    Recent progresses in nanotechnology fabrication gives the opportunity to build highly functional nano-devices. 3D structures based on noble metals or covered by them can be realized down to the nano-scales, obtaining different devices with the functionalities of plasmonic nano-lenses or nano-probes. Here, nano-cones decorated with silver nano-grains were fabricated using advanced nano-fabrication techniques. In fabricating the cones, the angle of the apex was varied over a significant range and, in doing so, different geometries were realized. In depositing the silver nano-particles, the concentration of solution was varied, whereby different growth conditions were realized. The combined effect of tip geometry and growth conditions influences the size and distribution of the silver nano grains. The tips have the ability to guide or control the growth of the grains, in the sense that the nano-particles would preferentially distribute along the cone, and especially at the apex of the cone, with no o minor concentration effects on the substrate. The arrangement of metallic nano-particles into three-dimensional (3D) structures results in a Surface Enhanced Raman Spectroscopy (SERS) device with improved interface with analytes compared to bi-dimensional arrays of metallic nanoparticles. In the future, similar devices may find application in microfluidic devices, and in general in flow chambers, where the system can be inserted as to mimic a a nano-bait, for the recognition of specific biomarkers, or the manipulation and chemical investigation of single cells directly in native environments with good sensitivity, repeatability and selectivity.

  5. Plasmonic 3D-structures based on silver decorated nanotips for biological sensing

    KAUST Repository

    Coluccio, M. L.

    2015-05-01

    Recent progresses in nanotechnology fabrication gives the opportunity to build highly functional nano-devices. 3D structures based on noble metals or covered by them can be realized down to the nano-scales, obtaining different devices with the functionalities of plasmonic nano-lenses or nano-probes. Here, nano-cones decorated with silver nano-grains were fabricated using advanced nano-fabrication techniques. In fabricating the cones, the angle of the apex was varied over a significant range and, in doing so, different geometries were realized. In depositing the silver nano-particles, the concentration of solution was varied, whereby different growth conditions were realized. The combined effect of tip geometry and growth conditions influences the size and distribution of the silver nano grains. The tips have the ability to guide or control the growth of the grains, in the sense that the nano-particles would preferentially distribute along the cone, and especially at the apex of the cone, with no o minor concentration effects on the substrate. The arrangement of metallic nano-particles into three-dimensional (3D) structures results in a Surface Enhanced Raman Spectroscopy (SERS) device with improved interface with analytes compared to bi-dimensional arrays of metallic nanoparticles. In the future, similar devices may find application in microfluidic devices, and in general in flow chambers, where the system can be inserted as to mimic a a nano-bait, for the recognition of specific biomarkers, or the manipulation and chemical investigation of single cells directly in native environments with good sensitivity, repeatability and selectivity. © 2015 Elsevier Ltd.

  6. Study of surface-modified PVP gate dielectric in organic thin film transistors with the nano-particle silver ink source/drain electrode.

    Science.gov (United States)

    Yun, Ho-Jin; Ham, Yong-Hyun; Shin, Hong-Sik; Jeong, Kwang-Seok; Park, Jeong-Gyu; Choi, Deuk-Sung; Lee, Ga-Won

    2011-07-01

    We have fabricated the flexible pentacene based organic thin film transistors (OTFTs) with formulated poly[4-vinylphenol] (PVP) gate dielectrics treated by CF4/O2 plasma on poly[ethersulfones] (PES) substrate. The solution of gate dielectrics is made by adding methylated poly[melamine-co-formaldehyde] (MMF) to PVP. The PVP gate dielectric layer was cross linked at 90 degrees under UV ozone exposure. Source/drain electrodes are formed by micro contact printing (MCP) method using nano particle silver ink for the purposes of low cost and high throughput. The optimized OTFT shows the device performance with field effect mobility of the 0.88 cm2/V s, subthreshold slope of 2.2 V/decade, and on/off current ratios of 1.8 x 10(-6) at -40 V gate bias. We found that hydrophobic PVP gate dielectric surface can influence on the initial film morphologies of pentacene making dense, which is more important for high performance OTFTs than large grain size. Moreover, hydrophobic gate dielelctric surface reduces voids and -OH groups that interrupt the carrier transport in OTFTs.

  7. Silver matrix composites reinforced with galvanically silvered particles

    OpenAIRE

    J. Śleziona; J. Wieczorek,

    2007-01-01

    Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powd...

  8. Aqueous Dissolution of Silver Iodide and Associated Iodine Release Under Reducing Conditions with Sulfide

    International Nuclear Information System (INIS)

    Yaohiro Inagaki; Toshitaka Imamura; Kazuya Idemitsu; Tatsumi Arima; Osamu Kato; Hidekazu Asano; Tsutomu Nishimura

    2007-01-01

    Aqueous dissolution tests of silver iodide (AgI) were performed in Na 2 S solutions in order to evaluate, empirically, dissolution of AgI to release iodine under reducing conditions with sulfide. The results indicated that AgI dissolves to release iodine being controlled by mainly precipitation of Ag 2 S. However, the dissolution of AgI can be depressed to proceed, and the thermodynamic equilibrium cannot be attained easily. Solid phase analysis for the reacted AgI suggested that a thin layer of solid silver forming at AgI surface may evolve to be protective against transportation of reactant species, which can lead to the depression in the dissolution of AgI. (authors)

  9. One-step synthesis of PbSe-ZnSe composite thin film

    Directory of Open Access Journals (Sweden)

    Abe Seishi

    2011-01-01

    Full Text Available Abstract This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

  10. Photo-induced valence change of the sulfur atom in an L-cysteine thin film grown on a silver metal substrate in a saliva-emulated aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Tsujibayashi, Toru [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Azuma, Junpei; Yamamoto, Isamu; Takahashi, Kazutoshi; Kamada, Masao [Synchrotron Light Application Center, Saga University, 1 Honjo, Saga, Saga 840-8502 (Japan)

    2015-04-27

    A thin film of L-cysteine (HSCH{sub 2}CH(NH{sub 2})COOH) is grown on a silver substrate in saliva-emulated aqueous solution. X-ray photoemission spectroscopic measurements have revealed that the sulfur atom shows valence change under IR laser irradiation at 825 nm. The valence change maintains for about a minute at room temperature and more than an hour between 110 and 250 K after stopping the laser irradiation. It is not observed at all at temperatures lower than 110 K. This temperature-dependent behavior indicates that the photo-excited electronic change should be accompanied by a conformational change in the L-cysteine molecule. It is strongly suggested that the reversible valence change of the sulfur atom is applicable to a memory used around room temperature.

  11. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José

    2010-10-24

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

  12. Photochemical Study of Silver Nanoparticles Formed from the Reduction of Silver Ions by Humic Acid

    Science.gov (United States)

    Leslie, Renee M.

    This study focuses on the ability of silver ions and humic acid to form silver nanoparticles in the presence of UV and visible light. Silver nanoparticles have a number of industrial applications due primarily to their antimicrobial properties, but these properties pose an environmental threat. Silver nanoparticles can directly disrupt sensitive ecosystems by harming bacteria. Consumption of silver nanoparticles results in silver ions and silver nanoparticles entering waterways; the presence of silver ions raises the question of whether nanoparticles can reform in environmental waters. As our data show, silver nanoparticles can form from the reduction of silver ions by humic acid after irradiation with UV and visible light. In order to better understand the mechanism of these naturally synthesized silver nanoparticles, we investigated the effects of reactant concentration, experimental conditions and presence of ions/reactive species. We monitored silver nanoparticle growth with UV-visible spectroscopy. The evolution in time of nanoparticle size was monitored by dynamic light scattering (DLS).

  13. Nanoscale photoelectron ionisation detector based on lanthanum hexaboride

    International Nuclear Information System (INIS)

    Zimmer, C.M.; Kunze, U.; Schubert, J.; Hamann, S.; Doll, T.

    2011-01-01

    A nanoscale ioniser is presented exceeding the limitation of conventional photoionisation detectors. It employs accelerated photoelectrons that allow obtaining molecule specificity by the tuning of ionisation energies. The material lanthanum hexaboride (LaB 6 ) is used as air stable photo cathode. Thin films of that material deposited by pulsed laser deposition (PLD) show quantum efficiency (QE) in the range of 10 -5 which is comparable to laser photo stimulation results. A careful treatment of the material yields reasonable low work functions even after surface reoxidation which opens up the possibility of using ultraviolet light emitting diodes (UV LEDs) in replacement of discharge lamps. Schematic diagram of a photoelectron ionisation detector (PeID) operating by an electron emitter based on the photoelectric effect of lanthanum hexaboride. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Study of Immobilization Procedure on Silver Nanolayers and Detection of Estrone with Diverged Beam Surface Plasmon Resonance (SPR Imaging

    Directory of Open Access Journals (Sweden)

    Ibrahim Abdulhalim

    2013-03-01

    Full Text Available An immobilization protocol was developed to attach receptors on smooth silver thin films. Dense and packed 11-mercaptoundecanoic acid (11-MUA was used to avoid uncontrolled sulfidization and harmful oxidation of silver nanolayers. N,N'-dicyclohexylcarbodiimide (DCC and N-hydroxysuccinimide (NHS were added to make the silver surfaces reactive. A comparative study was carried out with different immersion times of silver samples in 11-MUA solutions with different concentrations to find the optimum conditions for immobilization. The signals, during each step of the protocol, were analyzed with a refractometer based on the surface plasmon resonance (SPR effect and luminescence techniques. Molecular interactions at the surfaces between the probe and target at the surface nanolayer shift the SPR signal, thus indicating the presence of the substance. To demonstrate specific biosensing, rabbit anti-estrone polyclonal immunoglobulin G (IgG antibody was immobilized through a linker on 47 nm silver layer deposited on SF11 glass. At the final stage, the representative endocrine disruptor—estrone—was attached and detected in deionized water with a diverging beam SPR imaging sensor.

  15. Mineral commodity profiles: Silver

    Science.gov (United States)

    Butterman, W.C.; Hilliard, Henry E.

    2005-01-01

    Overview -- Silver is one of the eight precious, or noble, metals; the others are gold and the six platinum-group metals (PGM). World mine production in 2001 was 18,700 metric tons (t) and came from mines in 60 countries; the 10 leading producing countries accounted for 86 percent of the total. The largest producer was Mexico, followed by Peru, Australia, and the United States. About 25 percent of the silver mined in the world in 2001 came from silver ores; 15 percent, from gold ores and the remaining 60 percent, from copper, lead, and zinc ores. In the United States, 14 percent of the silver mined in 2001 came from silver ores; 39 percent, from gold ores; 10 percent, from copper and copper-molybdenum ores; and 37 percent, from lead, zinc, and lead-zinc ores. The precious metal ores (gold and silver) came from 30 lode mines and 10 placer mines; the base-metal ores (copper, lead, molybdenum, and zinc) came from 24 lode mines. Placer mines yielded less than 1 percent of the national silver production. Silver was mined in 12 States, of which Nevada was by far the largest producer; it accounted for nearly one-third of the national total. The production of silver at domestic mines generated employment for about 1,100 mine and mill workers. The value of mined domestic silver was estimated to be $290 million. Of the nearly 27,000 t of world silver that was fabricated in 2001, about one-third went into jewelry and silverware, one-fourth into the light-sensitive compounds used in photography, and nearly all the remainder went for industrial uses, of which there were 7 substantial uses and many other small-volume uses. By comparison, 85 percent of the silver used in the United States went to photography and industrial uses, 8 percent to jewelry and silverware, and 7 percent to coins and medals. The United States was the largest consumer of silver followed by India, Japan, and Italy; the 13 largest consuming countries accounted for nearly 90 percent of the world total. In the

  16. Silver Flakes and Silver Dendrites for Hybrid Electrically Conductive Adhesives with Enhanced Conductivity

    Science.gov (United States)

    Ma, Hongru; Li, Zhuo; Tian, Xun; Yan, Shaocun; Li, Zhe; Guo, Xuhong; Ma, Yanqing; Ma, Lei

    2018-03-01

    Silver dendrites were prepared by a facile replacement reaction between silver nitrate and zinc microparticles of 20 μm in size. The influence of reactant molar ratio, reaction solution volume, silver nitrate concentration, and reaction time on the morphology of dendrites was investigated systematically. It was found that uniform tree-like silver structures are synthesized under the optimal conditions. Their structure can be described as a trunk, symmetrical branches, and leaves, which length scales of 5-10, 1-2 μm, and 100-300 nm, respectively. All features were systematically characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and x-ray powder diffraction. A hybrid fillers system using silver flakes and dendrites as electrically conductive adhesives (ECAs) exhibited excellent overall performance. This good conductivity can be attributed mainly to the synergy between the silver microflakes (5-20 μm sized irregular sheet structures) and dendrites, allowing more conductive pathways to be formed between the fillers. In order to further optimize the overall electrical conductivity, various mixtures of silver microflakes and silver dendrites were tested in ECAs, with results indicating that the highest conductivity was shown when the amounts of silver microflakes, silver dendrites and the polymer matrix were 69.4 wt.% (20.82 vol.%), 0.6 wt.% (0.18 vol.%), and 30.0 wt.% (79.00 vol.%), respectively. The corresponding mass ratio of silver flakes to silver dendrites was 347:3. The resistivity of ECAs reached as low as 1.7 × 10-4 Ω cm.

  17. Nanoscale drug delivery for targeted chemotherapy.

    Science.gov (United States)

    Xin, Yong; Huang, Qian; Tang, Jian-Qin; Hou, Xiao-Yang; Zhang, Pei; Zhang, Long Zhen; Jiang, Guan

    2016-08-28

    Despite significant improvements in diagnostic methods and innovations in therapies for specific cancers, effective treatments for neoplastic diseases still represent major challenges. Nanotechnology as an emerging technology has been widely used in many fields and also provides a new opportunity for the targeted delivery of cancer drugs. Nanoscale delivery of chemotherapy drugs to the tumor site is highly desirable. Recent studies have shown that nanoscale drug delivery systems not only have the ability to destroy cancer cells but may also be carriers for chemotherapy drugs. Some studies have demonstrated that delivery of chemotherapy via nanoscale carriers has greater therapeutic benefit than either treatment modality alone. In this review, novel approaches to nanoscale delivery of chemotherapy are described and recent progress in this field is discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

    Science.gov (United States)

    This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

  19. Nanoscale effects in interdiffusion

    International Nuclear Information System (INIS)

    Erdelyi, Z.; Langer, G.A.; Beke, D.L.; Csik, A.

    2007-01-01

    Complete text of publication follows. Diffusion on the nano/atomic scales in multilayers, thin films has many challenging features even if the role of structural defects can be neglected and 'only' the effects related to the nano/atomic scale raise. The most basic equations to describe the diffusion are Fick's equations. It is important to emphasize that the diffusion coefficient in Fick's equations is in general composition independent and Fick's classical equations do not include the stress effects, which can have important influence onto the diffusion especially on the nano/atomic scale. We illustrate that the continuum descriptions of the diffusion cannot be applied automatically on such short distances, the classical continuum approximations (Fick's laws) cannot describe correctly the atomic movements. They predict faster kinetics than the atomistic models and the interface shift is always proportional to the square root of the time. However, the kinetics can be even linear on the nano/atomic scale. We have shown from computer simulations that Fick's laws violate on the nanoscale either in completely or restricted miscible systems. This is strongly related to the discrete character of the system on the nanoscale and to the highly neglected fact in the literature that the diffusion coefficients depend on the composition. As will be seen the composition dependence of D is very important and has very significant influence on the diffusion kinetics on the nano/atomic scales. It originates from the fact that usually the diffusion coefficients are different in an A and in a B matrix. Consequently in case of a real interface, which is not atomically sharp, i.e. there is a more or less intermixed region between the pure A and B matrixes, the diffusion coefficient changes continuously while e.g. an A atom diffuses from the pure A matrix into the pure B. This feature can be also called diffusion asymmetry. We have also illustrated that in this case not only the

  20. Spintronics in nanoscale devices

    CERN Document Server

    Hedin, Eric R

    2013-01-01

    By exploiting the novel properties of quantum dots and nanoscale Aharonov-Bohm rings together with the electronic and magnetic properties of various semiconductor materials and graphene, researchers have conducted numerous theoretical and computational modeling studies and experimental tests that show promising behavior for spintronics applications. Spin polarization and spin-filtering capabilities and the ability to manipulate the electron spin state through external magnetic or electric fields have demonstrated the promise of workable nanoscale devices for computing and memory applications.

  1. Chemically-induced solid-state dewetting of thin Au films

    International Nuclear Information System (INIS)

    Gazit, Nimrod; Klinger, Leonid; Rabkin, Eugen

    2017-01-01

    We employed the solid state dewetting technique to produce nanoparticles of silver-gold alloy on a sapphire substrate. We deposited a thin gold layer on the substrate with alloy nanoparticles, and studied its thermal stability at low homological temperatures. We demonstrated that a large number of densely spaced holes form at the initial stages of dewetting of the gold layer with nanoparticles. A similar homogeneous gold film deposited on a bare sapphire substrate remained stable under identical annealing conditions, exhibiting the onset of dewetting at higher temperatures, and with a lower number of holes. We attributed the decreased thermal stability of the gold film deposited on the substrate with the silver-gold nanoparticles to accelerated grooving at the grain boundaries and triple junctions in the film. The grooving process is accelerated by the diffusion fluxes of Au atoms driven from the film towards the nanoparticles by the gradient of chemical potential. We developed a quantitative model of this chemically-induced dewetting process, and discussed its applicability for the design of better catalytic systems. Our work demonstrates that the chemical driving forces have to be reckoned with in the analysis of thermal stability of multicomponent thin films.

  2. Measurement of the isotope effect of the diffusion of silver and gold in gold and of silver in silver-gold alloys

    International Nuclear Information System (INIS)

    Wolter, D.

    1974-01-01

    The silver isotopes Ag 105 and Agsup(110m) and the gold isotopes Au 195 and Au 199 were used for isotope effect measurements. The isotope effect of the gold self-diffusion was measured on four monocrystals samples at about 850 0 C, that of silver in gold monocrystals at five different temperatures between 731 0 C and 1050 0 C. Furthermore, the isotope effect for silver at 904 0 C was measured on seven silver-gold alloys of varying silver concentration. The correlation factor was determined from the measurements. (HPOE/LH) [de

  3. AgSbSe{sub 2} and AgSb(S,Se){sub 2} thin films for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garza, J.G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Rodriguez, A.C.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2011-10-01

    Silver antimony selenide (AgSbSe{sub 2}) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb{sub 2}S{sub 3}), silver selenide (Ag{sub 2}Se), selenium (Se) and silver (Ag). Sb{sub 2}S{sub 3} thin film was prepared from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}, Ag{sub 2}Se from a solution containing AgNO{sub 3} and Na{sub 2}SeSO{sub 3} and Se thin films from an acidified solution of Na{sub 2}SeSO{sub 3}, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10{sup -3} Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe{sub 2} or AgSb(S,Se){sub 2} depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe{sub 2}/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V{sub oc} = 435 mV and J{sub sc} = 0.08 mA/cm{sup 2} under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe{sub 2} as an absorber material by a non-toxic selenization process is achieved.

  4. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma; Compuestos hidrofobicos e hidrofilicos de politiofeno, plata y yodo sintetizados por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, J.C.; Chavez, J.A. [IIM, UNAM, Circuito exterior, Ciudad Universitaria, 04510 Coyoacan, D.F. (Mexico); Olayo, M.G.; Cruz, G.J. [ININ, Apdo. Postal 18-1027, 11801 Mexico D.F. (Mexico)

    2007-07-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  5. Optical and electrical characterization of AgInS2 thin films deposited by spray pyrolysis

    International Nuclear Information System (INIS)

    Calixto-Rodriguez, M.; Martinez, H.; Calixto, M.E.; Pena, Y.; Martinez-Escobar, Dalia; Tiburcio-Silver, A.; Sanchez-Juarez, A.

    2010-01-01

    Silver indium sulfide (AgInS 2 ) thin films have been prepared by spray pyrolysis (SP) technique using silver acetate, indium acetate, and N, N-dimethylthiourea as precursor compounds. Films were deposited onto glass substrates at different substrate temperatures (T s ) and Ag:In:S ratios in the starting solutions. Optical transmission and reflection as well as electrical measurements were performed in order to study the effect of deposition parameters on the optical and electrical properties of AgInS 2 thin films. X-ray diffraction measurements were used to identify the deposited compounds. It was found that different compounds such as AgInS 2 , Ag 2 S, In 2 O 3 , and In 2 S 3 can be grown only by changing the Ag:In:S ratio in the starting solution and T s . So that, by carefully selecting the deposition parameters, single phase AgInS 2 thin films can be easily grown. Thin films obtained using a molar ratio of Ag:In:S = 1:1:2 and T s = 400 o C, have an optical band gap of 1.9 eV and n-type electrical conductivity with a value of 0.3 Ω -1 cm -1 in the dark.

  6. The growth of nanoscale ZnO films by pulsed-spray evaporation chemical vapor deposition and their structural, electric and optical properties

    International Nuclear Information System (INIS)

    Jiang Yinzhu; Bahlawane, Naoufal

    2010-01-01

    Great interest in nanoscale thin films (sub-100 nm) has been stimulated by the developing demands of functional devices. In this paper, nanoscale zinc oxide (ZnO) thin films were deposited on glass substrates at 300 o C by pulsed-spray evaporation chemical vapor deposition. Scanning electron micrographs indicate uniform surface morphologies composed of nanometer-sized spherical particles. The growth kinetics and growth mode are studied and the relationship between the film thickness and the electric properties with respect to the growth mode is interpreted. X-ray diffraction shows that all ZnO films grown by this process were crystallized in a hexagonal structure and highly oriented with their c-axes perpendicular to the plane of the substrate. Optical measurements show transparencies above 85% in the visible spectral range for all films. The absorbance in the UV spectral range respects well the Beer-Lambert law, enabling an accurate optical thickness measurement, and the absorption coefficient was measured for a selected wavelength. The measured band gap energies exhibit an almost constant value of 3.41 eV for all films with different thicknesses, which attributed to the thickness-independent crystallite size.

  7. Strategies towards controlling strain-induced mesoscopic phase separation in manganite thin films

    Science.gov (United States)

    Habermeier, H.-U.

    2008-10-01

    Complex oxides represent a class of materials with a plethora of fascinating intrinsic physical functionalities. The intriguing interplay of charge, spin and orbital ordering in these systems superimposed by lattice effects opens a scientifically rewarding playground for both fundamental as well as application oriented research. The existence of nanoscale electronic phase separation in correlated complex oxides is one of the areas in this field whose impact on the current understanding of their physics and potential applications is not yet clear. In this paper this issue is treated from the point of view of complex oxide thin film technology. Commenting on aspects of complex oxide thin film growth gives an insight into the complexity of a reliable thin film technology for these materials. Exploring fundamentals of interfacial strain generation and strain accommodation paves the way to intentionally manipulate thin film properties. Furthermore, examples are given for an extrinsic continuous tuning of intrinsic electronic inhomogeneities in perovskite-type complex oxide thin films.

  8. Strategies towards controlling strain-induced mesoscopic phase separation in manganite thin films

    International Nuclear Information System (INIS)

    Habermeier, H-U

    2008-01-01

    Complex oxides represent a class of materials with a plethora of fascinating intrinsic physical functionalities. The intriguing interplay of charge, spin and orbital ordering in these systems superimposed by lattice effects opens a scientifically rewarding playground for both fundamental as well as application oriented research. The existence of nanoscale electronic phase separation in correlated complex oxides is one of the areas in this field whose impact on the current understanding of their physics and potential applications is not yet clear. In this paper this issue is treated from the point of view of complex oxide thin film technology. Commenting on aspects of complex oxide thin film growth gives an insight into the complexity of a reliable thin film technology for these materials. Exploring fundamentals of interfacial strain generation and strain accommodation paves the way to intentionally manipulate thin film properties. Furthermore, examples are given for an extrinsic continuous tuning of intrinsic electronic inhomogeneities in perovskite-type complex oxide thin films.

  9. Bioplasmonic Alloyed Nanoislands Using Dewetting of Bilayer Thin Films.

    Science.gov (United States)

    Kang, Minhee; Ahn, Myeong-Su; Lee, Youngseop; Jeong, Ki-Hun

    2017-10-25

    Unlike monometallic materials, bimetallic plasmonic materials offer extensive benefits such as broadband tuning capability or high environmental stability. Here we report a broad range tuning of plasmon resonance of alloyed nanoislands by using solid-state dewetting of gold and silver bilayer thin films. Thermal dewetting after successive thermal evaporation of thin metal double-layer films readily forms AuAg-alloyed nanoislands with a precise composition ratio. The complete miscibility of alloyed nanoislands results in programmable tuning of plasmon resonance wavelength in a broadband visible range. Such extraordinary tuning capability opens up a new direction for plasmonic enhancement in biophotonic applications such as surface-enhanced Raman scattering or plasmon-enhanced fluorescence.

  10. Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

    Energy Technology Data Exchange (ETDEWEB)

    Uznanski, Pawel, E-mail: puznansk@cbmm.lodz.pl; Zakrzewska, Joanna [Centre of Molecular and Macromolecular Studies, PAS (Poland); Favier, Frederic, E-mail: fredf@univ-montp2.fr [Université Montpellier II, ICGM - UMR5253- Equipe AIME (France); Kazmierski, Slawomir; Bryszewska, Ewa [Centre of Molecular and Macromolecular Studies, PAS (Poland)

    2017-03-15

    A comparative study of amine and silver carboxylate adducts [R{sub 1}COOAg-2(R{sub 2}NH{sub 2})] (R{sub 1} = 1, 7, 11; R{sub 2} = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, {sup 13}C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies ({sup 1}H and {sup 13}C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism.

  11. Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

    Science.gov (United States)

    Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

    2012-01-01

    The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

  12. Optical Materials with a Genome: Nanophotonics with DNA-Stabilized Silver Clusters

    Science.gov (United States)

    Copp, Stacy M.

    Fluorescent silver clusters with unique rod-like geometries are stabilized by DNA. The sizes and colors of these clusters, or AgN-DNA, are selected by DNA base sequence, which can tune peak emission from blue-green into the near-infrared. Combined with DNA nanostructures, AgN-DNA promise exciting applications in nanophotonics and sensing. Until recently, however, a lack of understanding of the mechanisms controlling AgN-DNA fluorescence has challenged such applications. This dissertation discusses progress toward understanding the role of DNA as a "genome" for silver clusters and toward using DNA to achieve atomic-scale precision of silver cluster size and nanometer-scale precision of silver cluster position on a DNA breadboard. We also investigate sensitivity of AgN-DNA to local solvent environment, with an eye toward applications in chemical and biochemical sensing. Using robotic techniques to generate large data sets, we show that fluorescent silver clusters are templated by certain DNA base motifs that select "magic-sized" cluster cores of enhanced stabilities. The linear arrangement of bases on the phosphate backbone imposes a unique rod-like geometry on the clusters. Harnessing machine learning and bioinformatics techniques, we also demonstrate that sequences of DNA templates can be selected to stabilize silver clusters with desired optical properties, including high fluorescence intensity and specific fluorescence wavelengths, with much higher rates of success as compared to current strategies. The discovered base motifs can be also used to design modular DNA host strands that enable individual silver clusters with atomically precise sizes to bind at specific programmed locations on a DNA nanostructure. We show that DNA-mediated nanoscale arrangement enables near-field coupling of distinct clusters, demonstrated by dual-color cluster assemblies exhibiting resonant energy transfer. These results demonstrate a new degree of control over the optical properties

  13. Nanoscale phase change memory materials.

    Science.gov (United States)

    Caldwell, Marissa A; Jeyasingh, Rakesh Gnana David; Wong, H-S Philip; Milliron, Delia J

    2012-08-07

    Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.

  14. Gravimetric and volumetric determination of the purity of electrolytically refined silver and the produced silver nitrate

    Directory of Open Access Journals (Sweden)

    Ačanski Marijana M.

    2007-01-01

    Full Text Available Silver is, along with gold and the platinum-group metals, one of the so called precious metals. Because of its comparative scarcity, brilliant white color, malleability and resistance to atmospheric oxidation, silver has been used in the manufacture of coins and jewelry for a long time. Silver has the highest known electrical and thermal conductivity of all metals and is used in fabricating printed electrical circuits, and also as a coating for electronic conductors. It is also alloyed with other elements such as nickel or palladium for use in electrical contacts. The most useful silver salt is silver nitrate, a caustic chemical reagent, significant as an antiseptic and as a reagent in analytical chemistry. Pure silver nitrate is an intermediate in the industrial preparation of other silver salts, including the colloidal silver compounds used in medicine and the silver halides incorporated into photographic emulsions. Silver halides become increasingly insoluble in the series: AgCl, AgBr, AgI. All silver salts are sensitive to light and are used in photographic coatings on film and paper. The ZORKA-PHARMA company (Sabac, Serbia specializes in the production of pharmaceutical remedies and lab chemicals. One of its products is chemical silver nitrate (argentum-nitricum (l. Silver nitrate is generally produced by dissolving pure electrolytically refined silver in hot 48% nitric acid. Since the purity of silver nitrate, produced in 2002, was not in compliance with the p.a. level of purity, there was doubt that the electrolytically refined silver was pure. The aim of this research was the gravimetric and volumetric determination of the purity of electrolytically refined silver and silver nitrate, produced industrially and in a laboratory. The purity determination was carried out gravimetrically, by the sedimentation of silver(I ions in the form of insoluble silver salts: AgCl, AgBr and Agi, and volumetrically, according to Mohr and Volhardt. The

  15. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Science.gov (United States)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-10-01

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  16. Nano-scale pattern formation on the surface of HgCdTe produced by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.B.; Gudymenko, A.I.; Kladko, V.P.; Korchevyi, A.A.; Savkina, R.K.; Sizov, F.F.; Udovitska, R.S. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kiev (Ukraine)

    2015-08-15

    Presented in this work are the results concerning formation of nano-scale patterns on the surface of a ternary compound Hg{sub 1-x}Cd{sub x}Te (x ∝ 0.223). Modification of this ternary chalcogenide semiconductor compound was performed using the method of oblique-incidence ion bombardment with silver ions, which was followed by low-temperature treatment. The energy and dose of implanted ions were 140 keV and 4.8 x 10{sup 13} cm{sup -2}, respectively. Atomic force microscopy methods were used for the surface topography characterization. The structural properties of MCT-based structure was analyzed using double and triple crystal X-ray diffraction to monitor the disorder and strain of the implanted region as a function of processing conditions. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Nanoscale mechanical switching of ferroelectric polarization via flexoelectricity

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Yijia; Hong, Zijian; Britson, Jason; Chen, Long-Qing [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2015-01-12

    Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for device applications. Using the phase-field method, we study the mechanical switching of electric polarization in ferroelectric thin films by a strain gradient created via an atomic force microscope tip. Our simulation results show good agreement with existing experimental observations. We examine the competition between the piezoelectric and flexoelectric effects and provide an understanding of the role of flexoelectricity in the polarization switching. Also, by changing the pressure and film thickness, we reveal that the flexoelectric field at the film bottom can be used as a criterion to determine whether domain switching may happen under a mechanical force.

  18. Surface characterization and biological evaluation of silver-incorporated DLC coatings fabricated by hybrid RF PACVD/MS method.

    Science.gov (United States)

    Bociąga, Dorota; Jakubowski, Witold; Komorowski, Piotr; Sobczyk-Guzenda, Anna; Jędrzejczak, Anna; Batory, Damian; Olejnik, Anna

    2016-06-01

    Since the biological response of the body towards an implanted material is mainly governed by its surface properties, biomaterials are improved by various kinds of coatings. Their role is to provide good mechanical and biological characteristics, and exclude some disadvantages like post-implantation infections. This phenomenon may be reduced by introduction of silver as an antibacterial agent. This study evaluates the Ag-DLC films synthesized by the hybrid RF PACVD/MS method according to the patent number PL401955-A1 worked out inter alia by the authors. Such tests as XPS, SEM, EDS, AFM, FTIR, Raman and ICP-TOF-MS were used to determine surface properties of the coatings. The obtained results were correlated with the biological response estimated on the basis of cells viability assay (osteoblast cells line Saos-2) and bacterial colonization test (Escherichia coli strain DH5α). Results showed that the hybrid RF PACVD/MS method allows one to get tight coating preventing the diffusion of harmful elements from the metallic substrate. Ag concentration increases with the growing power density, it occurs in metallic state, does not create chemical bonds and is evenly dispersed within the DLC matrix in the form of nanoscale silver clusters. Increasing silver content above 2at.% improves bactericidal properties, but decreases cell viability. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. In vitro percutaneous penetration and characterization of silver from silver-containing textiles

    Directory of Open Access Journals (Sweden)

    Bianco C

    2015-03-01

    Full Text Available Carlotta Bianco,1 Sanja Kezic,2 Matteo Crosera,1 Vesna Svetličić,3 Suzana Šegota,3 Giovanni Maina,4 Canzio Romano,5 Francesca Larese,6,7 Gianpiero Adami11Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy; 2Academic Medical Center, Coronel Institute, University of Amsterdam, Amsterdam, the Netherlands; 3Laboratory for Bioelectrochemistry and Surface Imaging, Division for Marine and Environmental Research, Ruder Boškovic Institute, Zagreb, Croatia; 4Department of Clinical and Biological Sciences, University of Turin, Turin, Italy; 5Department of Public and Pediatric Health Sciences, University of Turin, Turin, Italy; 6Unit of Occupational Medicine, University of Trieste, Trieste, Italy; 7Department of Medical Sciences, University of Trieste, Trieste, ItalyAbstract: The objective of this study was to determine the in vitro percutaneous penetration of silver and characterize the silver species released from textiles in different layers of full thickness human skin. For this purpose, two different wound dressings and a garment soaked in artificial sweat were placed in the donor compartments of Franz cells for 24 hours. The concentration of silver in the donor phase and in the skin was determined by an electrothermal atomic absorption spectrometer (ET-AAS and by inductively coupled plasma mass spectrometer (ICP-MS. The characterization of silver species in the textiles and in the skin layers was made by scanning electron microscopy with integrated energy dispersive X-ray spectroscopy (SEM-EDX. Additionally, the size distribution of silver nanoparticles in the textiles was performed by atomic force microscopy (AFM. On the surface of all investigated materials, silver nanoparticles of different size and morphology were found. Released silver concentrations in the soaking solutions (ie, exposure concentration ranged from 0.7 to 4.7 µg/mL (0.6–4.0 µg/cm2, fitting the bactericidal range. Silver and silver

  20. Plasmonic characterization of photo-induced silver nanoparticles extracted from silver halide based TEM film

    Energy Technology Data Exchange (ETDEWEB)

    Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.; Srivastava, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Varshney, G. K. [Laser Bio-medical Applications & Instrumentation Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India)

    2016-05-23

    The plasmonic responses of silver nanoparticles extracted from silver halide based electron microscope film are investigated. Photo-reduction process is carried out to convert the silver halide grains into the metallic silver. The centrifuge technique is used for separating the silver nanoparticles from the residual solution. Morphological study performed by field emission scanning electron microscope (FESEM) shows that all the nanoparticles have an average diameter of ~120 nm with a high degree of mono dispersion in size. The localized surface plasmon resonance (LSPR) absorption peak at ~537 nm confirms the presence of large size silver nanoparticles.

  1. Role of SiC substrate surface on local tarnishing of deposited silver mirror stacks

    Science.gov (United States)

    Limam, Emna; Maurice, Vincent; Seyeux, Antoine; Zanna, Sandrine; Klein, Lorena H.; Chauveau, Grégory; Grèzes-Besset, Catherine; Savin De Larclause, Isabelle; Marcus, Philippe

    2018-04-01

    The role of the SiC substrate surface on the resistance to the local initiation of tarnishing of thin-layered silver stacks for demanding space mirror applications was studied by combined surface and interface analysis on model stack samples deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous H2S. It is shown that suppressing the surface pores resulting from the bulk SiC material production process by surface pretreatment eliminates the high aspect ratio surface sites that are imperfectly protected by the SiO2 overcoat after the deposition of silver. The formation of channels connecting the silver layer to its environment through the failing protection layer at the surface pores and locally enabling H2S entry and Ag2S growth as columns until emergence at the stack surface is suppressed, which markedly delays tarnishing initiation and thereby preserves the optical performance. The results revealed that residual tarnishing initiation proceeds by a mechanism essentially identical in nature but involving different pathways short circuiting the protection layer and enabling H2S ingress until the silver layer. These permeation pathways are suggested to be of microstructural origin and could correspond to the incompletely coalesced intergranular boundaries of the SiO2 layer.

  2. Nanoscale reduction of graphene oxide thin films and its characterization.

    Science.gov (United States)

    Lorenzoni, M; Giugni, A; Di Fabrizio, E; Pérez-Murano, Francesc; Mescola, A; Torre, B

    2015-07-17

    In this paper, we report on a method to reduce thin films of graphene oxide (GO) to a spatial resolution better than 100 nm over several tens of micrometers by means of an electrochemical scanning probe based lithography. In situ tip-current measurements show that an edged drop in electrical resistance characterizes the reduced areas, and that the reduction process is, to a good approximation, proportional to the applied bias between the onset voltage and the saturation thresholds. An atomic force microscope (AFM) quantifies the drop of the surface height for the reduced profile due to the loss of oxygen. Complementarily, lateral force microscopy reveals a homogeneous friction coefficient of the reduced regions that is remarkably lower than that of native graphene oxide, confirming a chemical change in the patterned region. Micro Raman spectroscopy, which provides access to insights into the chemical process, allows one to quantify the restoration and de-oxidation of the graphitic network driven by the electrochemical reduction and to determine characteristic length scales. It also confirms the homogeneity of the process over wide areas. The results shown were obtained from accurate analysis of the shift, intensity and width of Raman peaks for the main vibrational bands of GO and reduced graphene oxide (rGO) mapped over large areas. Concerning multilayered GO thin films obtained by drop-casting we have demonstrated an unprecedented lateral resolution in ambient conditions as well as an improved control, characterization and understanding of the reduction process occurring in GO randomly folded multilayers, useful for large-scale processing of graphene-based material.

  3. Synthesis and characterization of silver nanoparticles by sol-gel route from silver nitrate

    International Nuclear Information System (INIS)

    Morales, Jorge; Moran, Jose; Quintana, Maria; Estrada, Walter

    2009-01-01

    Silver nanoparticles colloids have been synthesized by sol-gel method. This synthesis consists in silver nitrate reduction by ethylene glycol in a process called polyol. The growth of the nanoparticles have been controlled by the steric stabilization of the colloid with polyvinylpyrrolidone (PVP, M w = 40 000). The silver nanoparticle size and structure was depending on the control of parameters such as: molar concentrations ratio of silver nitrate and PVP, temperature of reaction and the reflux time. Colloids have been characterized by UV-vis spectroscopy in the range from 300 to 1000 nm. The results show that the typical peak of surface plasmon resonance is formed at 400-450 nm indicating the formation of silver nanoparticles. The presences of silver nanoparticles of spherical shape with size among 20-40 nm were observed by transmission electronic microscopy (TEM). Electron diffraction patterns confirmed that synthesized colloids contain metallic silver with a crystal structure face centered cubic FCC. (author)

  4. Nanoscale devices based on plasmonic coaxial waveguide resonators

    Science.gov (United States)

    Mahigir, A.; Dastmalchi, P.; Shin, W.; Fan, S.; Veronis, G.

    2015-02-01

    Waveguide-resonator systems are particularly useful for the development of several integrated photonic devices, such as tunable filters, optical switches, channel drop filters, reflectors, and impedance matching elements. In this paper, we introduce nanoscale devices based on plasmonic coaxial waveguide resonators. In particular, we investigate threedimensional nanostructures consisting of plasmonic coaxial stub resonators side-coupled to a plasmonic coaxial waveguide. We use coaxial waveguides with square cross sections, which can be fabricated using lithography-based techniques. The waveguides are placed on top of a silicon substrate, and the space between inner and outer coaxial metals is filled with silica. We use silver as the metal. We investigate structures consisting of a single plasmonic coaxial resonator, which is terminated either in a short or an open circuit, side-coupled to a coaxial waveguide. We show that the incident waveguide mode is almost completely reflected on resonance, while far from the resonance the waveguide mode is almost completely transmitted. We also show that the properties of the waveguide systems can be accurately described using a single-mode scattering matrix theory. The transmission and reflection coefficients at waveguide junctions are either calculated using the concept of the characteristic impedance or are directly numerically extracted using full-wave three-dimensional finite-difference frequency-domain simulations.

  5. The influence of nanoscale morphology on the resistivity of cluster-assembled nanostructured metallic thin films

    International Nuclear Information System (INIS)

    Barborini, E; Bertolini, G; Repetto, P; Leccardi, M; Vinati, S; Corbelli, G; Milani, P

    2010-01-01

    We have studied in situ the evolution of the electrical resistivity of Fe, Pd, Nb, W and Mo cluster-assembled films during their growth by supersonic cluster beam deposition. We observed resistivity of cluster-assembled films several orders of magnitude larger than the bulk, as well as an increase in resistivity by increasing the film thickness in contrast to what was observed for atom-assembled metallic films. This suggests that the nanoscale morphological features typical of ballistic films growth, such as the minimal cluster-cluster interconnection and the evolution of surface roughness with thickness, are responsible for the observed behaviour.

  6. Nanoscale measurement of Nernst effect in two-dimensional charge density wave material 1T-TaS2

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Stephen M. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA; Luican-Mayer, Adina [Nanoscience and Technology Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada; Bhattacharya, Anand [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Nanoscience and Technology Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

    2017-11-27

    Advances in nanoscale material characterization on two-dimensional van der Waals layered materials primarily involve their optical and electronic properties. The thermal properties of these materials are harder to access due to the difficulty of thermal measurements at the nanoscale. In this work, we create a nanoscale magnetothermal device platform to access the basic out-of-plane magnetothermal transport properties of ultrathin van der Waals materials. Specifically, the Nernst effect in the charge density wave transition metal dichalcogenide 1T-TaS2 is examined on nano-thin flakes in a patterned device structure. It is revealed that near the commensurate charge density wave (CCDW) to nearly commensurate charge density wave (NCCDW) phase transition, the polarity of the Nernst effect changes. Since the Nernst effect is especially sensitive to changes in the Fermi surface, this suggests that large changes are occurring in the out-of-plane electronic structure of 1T-TaS2, which are otherwise unresolved in just in-plane electronic transport measurements. This may signal a coherent evolution of out-of-plane stacking in the CCDW! NCCDW transition.

  7. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-10-15

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  8. Physical IC debug ─ backside approach and nanoscale challenge

    Directory of Open Access Journals (Sweden)

    U. Kerst

    2008-05-01

    Full Text Available Physical analysis for IC functionality in submicron technologies requires access through chip backside. Based upon typical global backside preparation with 50–100 µm moderate silicon thickness remaining, a state of the art of the analysis techniques available for this purpose is presented and evaluated for functional analysis and layout pattern resolution potential. A circuit edit technique valid for nano technology ICs, is also presented that is based upon the formation of local trenches using the bottom of Shallow Trench Isolation (STI as endpoint for Focused Ion Beam (FIB milling. As a derivative from this process, a locally ultra thin silicon device can be processed, creating a back surface as work bench for breakthrough applications of nanoscale analysis techniques to a fully functional circuit through chip backside. Several applications demonstrate the power and potential of this new approach.

  9. Frictional properties of self-adaptive chromium doped tungsten–sulfur–carbon coatings at nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Zekonyte, J., E-mail: j.zekonyte@soton.ac.uk [National Centre for Advanced Tribology, Faculty of Engineering and Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Cavaleiro, A. [SEG-CEMUC – Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, P-3030 788 Coimbra (Portugal); Polcar, T. [National Centre for Advanced Tribology, Faculty of Engineering and Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic)

    2014-06-01

    Transition metal dichalcogenides (TMD) are excellent dry lubricants forming thin (∼10 nm) tribolayer that simultaneously protects the coating from environmental attack and provides low friction. In this paper, we focus on nanoscale frictional properties of chromium doped tungsten–sulfur–carbon (WSC–Cr) coatings with various Cr content. Friction force microscopy was used to investigate friction force as a function of load. A non-linear contact area dependence on the normal force was observed. The calculated interfacial shear strength was relatively low in the region of 70–99 MPa. Friction coefficient decreased with increased applied load independently of chromium content in the coatings.

  10. Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

    Science.gov (United States)

    Liu, Suwen; Wehmschulte, Rudolf J.; Lian, Guoda; Burba, Christopher M.

    2006-03-01

    Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD).

  11. Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

    International Nuclear Information System (INIS)

    Liu Suwen; Wehmschulte, Rudolf J.; Lian Guoda; Burba, Christopher M.

    2006-01-01

    Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD)

  12. Electrical four-point probing of spherical metallic thin films coated onto micron sized polymer particles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Sigurd R., E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no; Stokkeland, August Emil; Zhang, Zhiliang; He, Jianying, E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Kristiansen, Helge [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway); Njagi, John; Goia, Dan V. [Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5814 (United States); Redford, Keith [Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway)

    2016-07-25

    Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver-coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 μm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

  13. Fractionation of silver isotopes in native silver explained by redox reactions

    Science.gov (United States)

    Mathur, Ryan; Arribas, Antonio; Megaw, Peter; Wilson, Marc; Stroup, Steven; Meyer-Arrivillaga, Danilo; Arribas, Isabel

    2018-03-01

    Scant data exist on the silver isotope composition of native silver specimens because of the relative newness of the technique. This study increases the published dataset by an order of magnitude and presents 80 silver new isotope analyses from native silver originating from a diverse set of worldwide deposits (8 deposit types, 33 mining districts in five continents). The measured isotopic range (defined as δ109Ag/107Ag in per mil units compared to NIST 978 Ag isotope standard) is +2.1 to -0.86‰ (2σ errors less than 0.015); with no apparent systematic correlations to date with deposit type or even within districts. Importantly, the data centering on 0‰ all come from high temperature hypogene/primary deposits whereas flanking and overlapping data represent secondary supergene deposits. To investigate the causes for the more fractionated values, several laboratory experiments involving oxidation of silver from natural specimens of Ag-rich sulfides and precipitation and adsorption of silver onto reagent grade MnO2 and FeOOH were conducted. Simple leach experiments demonstrate little Ag isotope fractionation occurred through oxidation of Ag from native Ag (Δsolution-native109Ag = 0.12‰). In contrast, significant fractionation occurred through precipitation of native Ag onto MnO2 (up to Δsolution-MnO2109Ag = 0.68‰, or 0.3amu). Adsorption of silver onto the MnO2 and FeOOH did not produce as large fractionation as precipitation (mean value of Δsolution-MnO2109Ag = 0.10‰). The most likely cause for the isotopic variations seen relates to redox effects such as the reduction of silver from Ag (I) to Ag° that occurs during precipitation onto the mineral surface. Since many Ag deposits have halos dominated by MnO2 and FeOOH phases, potential may exist for the silver isotope composition of ores and surrounding geochemical haloes to be used to better understand ore genesis and potential exploration applications. Aside from the Mn oxides, surface fluid silver

  14. Entrapment of dye molecules within submicron silver particles

    Energy Technology Data Exchange (ETDEWEB)

    Yosef, Itzik; Avnir, David, E-mail: david@chem.ch.huji.ac.il [Hebrew University of Jerusalem, Institute of Chemistry (Israel)

    2011-09-15

    We describe a method for the preparation of metal-organic composites submicron particles. Specifically, the preparation of silver particle-clusters 150-200 nm in size, doped with an organic dye Congo-red, is reported. The use of sodium citrate coupled with sodium hypophosphite facilitated the formation of these particle-clusters, which were fully characterized by TEM analysis, Zeta potential and size measurements, scanning electron microscopy, UV-Vis measurements, and thermogravimetric analysis. The latter reveals a catalytic action of the metal on the thermal oxidative decomposition of the entrapped dye. The use of these particles to obtain dense thin metallic films was demonstrated by the coating of ITO glass.

  15. Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

    International Nuclear Information System (INIS)

    Petala, M.; Tsiridis, V.; Mintsouli, I.; Pliatsikas, N.; Spanos, Th.; Rebeyre, P.; Darakas, E.; Patsalas, P.; Vourlias, G.; Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th.

    2017-01-01

    Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

  16. Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Petala, M., E-mail: petala@civil.auth.gr [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Tsiridis, V. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Mintsouli, I. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Pliatsikas, N. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Spanos, Th. [Department of Petroleum and Mechanical Engineering Sciences, Eastern Macedonia and Thrace Institute of Technology, Kavala, 65404 (Greece); Rebeyre, P. [ESA/ESTEC, P.O.Box 299, 2200 AG, Noordwijk (Netherlands); Darakas, E. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Patsalas, P.; Vourlias, G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece)

    2017-02-28

    Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

  17. Multilayer Thin Films Sequential Assembly of Nanocomposite Materials

    CERN Document Server

    Decher, Gero

    2012-01-01

    This second, comprehensive edition of the pioneering book in this field has been completely revised and extended, now stretching to two volumes. The result is a comprehensive summary of layer-by-layer assembled, truly hybrid nanomaterials and thin films, covering organic, inorganic, colloidal, macromolecular and biological components, plus the assembly of nanoscale films derived from them on surfaces. Praise for the first edition: "... highly recommended to anyone interested in the field... and to scientists and researchers active in materials development..." –Polymer News With contri

  18. Thin Film Energy Storage Device with Spray‐Coated Sliver Paste Current Collector

    Directory of Open Access Journals (Sweden)

    Seong Man Yoon

    2017-12-01

    Full Text Available This paper challenges the fabrication of a thin film energy storage device on a flexible polymer substrate specifically by replacing most commonly used metal foil current collectors with coated current collectors. Mass‐manufacturable spray‐coating technology enables the fabrication of two different half‐cell electric double layer capacitors (EDLC with a spray‐coated silver paste current collector and a Ni foil current collector. The larger specific capacitances of the half‐cell EDLC with the spray‐coated silver current collector are obtained as 103.86 F/g and 76.8 F/g for scan rates of 10 mV/s and 500 mV/s, respectively. Further, even though the half‐cell EDLC with the spray‐coated current collector is heavier than that with the Ni foil current collector, smaller Warburg impedance and contact resistance are characterized from Nyquist plots. For the applied voltages ranging from −0.5 V to 0.5 V, the spray‐coated thin film energy storage device exhibits a better performance.

  19. Nanoscale reduction of graphene oxide thin films and its characterization

    KAUST Repository

    Lorenzoni, M.

    2015-06-29

    In this paper, we report on a method to reduce thin films of graphene oxide (GO) to a spatial resolution better than 100 nm over several tens of micrometers by means of an electrochemical scanning probe based lithography. In situ tip-current measurements show that an edged drop in electrical resistance characterizes the reduced areas, and that the reduction process is, to a good approximation, proportional to the applied bias between the onset voltage and the saturation thresholds. An atomic force microscope (AFM) quantifies the drop of the surface height for the reduced profile due to the loss of oxygen. Complementarily, lateral force microscopy reveals a homogeneous friction coefficient of the reduced regions that is remarkably lower than that of native graphene oxide, confirming a chemical change in the patterned region. Micro Raman spectroscopy, which provides access to insights into the chemical process, allows one to quantify the restoration and de-oxidation of the graphitic network driven by the electrochemical reduction and to determine characteristic length scales. It also confirms the homogeneity of the process over wide areas. The results shown were obtained from accurate analysis of the shift, intensity and width of Raman peaks for the main vibrational bands of GO and reduced graphene oxide (rGO) mapped over large areas. Concerning multilayered GO thin films obtained by drop-casting we have demonstrated an unprecedented lateral resolution in ambient conditions as well as an improved control, characterization and understanding of the reduction process occurring in GO randomly folded multilayers, useful for large-scale processing of graphene-based material. © 2015 IOP Publishing Ltd.

  20. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

    2015-08-31

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

  1. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    International Nuclear Information System (INIS)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung

    2015-01-01

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □ −1 and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □ −1 after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐ −1 ) and high transmittance (87.6%)

  2. Production of silver ions from colloidal silver by nanoparticle iontophoresis system.

    Science.gov (United States)

    Tseng, Kuo-Hsiung; Liao, Chih-Yu

    2011-03-01

    Metal ions, especially the silver ion, were used to treat infection before the initiation of antibiotic therapy. Unfortunately, there is a lack of research on the metallic nanoparticle suspension as a reservoir for metal ion release application. For medical purposes, conversion of colloidal silver into an ionic form is necessary, but not using silver salts (e.g., AgNO3, Ag2SO4), due to the fact that the counter-ion of silver salts may cause problems to the body as the silver ion (Ag+) is consumed. The goal of this research is to develop a silver nanoparticle iontophoresis system (NIS) which can provide a relatively safe bactericidal silver ion solution with a controllable electric field. In this study, ion-selective electrodes were used to identify and observe details of the system's activity. Both qualitative and quantitative data analyses were performed. The experimental results show that the ion releasing peak time (R(PT)) has an inversely proportional relationship with the applied current and voltage. The ion releasing maximum level (R(ML)) and dosage (R(D)) are proportional to the current density and inversely proportional to the voltage, respectively. These results reveal that the nanoparticle iontophoresis system (NIS) is an alternative method for the controlled release of a metal ion and the ion's concentration profile, by controlling the magnitude of current density (1 microA/cm2 equal to 1 ppm/hour) and applied voltage.

  3. Effect of the size of silver nanoparticles on SERS signal enhancement

    Science.gov (United States)

    He, Rui Xiu; Liang, Robert; Peng, Peng; Norman Zhou, Y.

    2017-08-01

    The localized surface plasmon resonance arising from plasmonic materials is beneficial in solution-based and thin-film sensing applications, which increase the sensitivity of the analyte being tested. Silver nanoparticles from 35 to 65 nm in diameter were synthesized using a low-temperature method and deposited in a monolayer on a (3-aminopropyl)triethoxysilane (APTES)-functionalized glass slide. The effect of particle size on monolayer structure, optical behavior, and surface-enhanced Raman scattering (SERS) is studied. While increasing particle size decreases particle coverage, it also changes the localized surface plasmon resonance and thus the SERS activity of individual nanoparticles. Using a laser excitation wavelength of 633 nm, the stronger localized surface plasmon resonance coupling to this excitation wavelength at larger particle sizes trumps the loss in surface coverage, and greater SERS signals are observed. The SERS signal enhancement accounts for the higher SERS signal, which was verified using a finite element model of a silver nanoparticle dimer with various nanoparticle sizes and separation distances.

  4. Tailoring the optical constants in single-crystal silicon with embedded silver nanostructures for advanced silicon photonics applications

    International Nuclear Information System (INIS)

    Akhter, Perveen; Huang, Mengbing; Spratt, William; Kadakia, Nirag; Amir, Faisal

    2015-01-01

    Plasmonic effects associated with metal nanostructures are expected to hold the key to tailoring light emission/propagation and harvesting solar energy in materials including single crystal silicon which remains the backbone in the microelectronics and photovoltaics industries but unfortunately, lacks many functionalities needed for construction of advanced photonic and optoelectronics devices. Currently, silicon plasmonic structures are practically possible only in the configuration with metal nanoparticles or thin film arrays on a silicon surface. This does not enable one to exploit the full potential of plasmonics for optical engineering in silicon, because the plasmonic effects are dominant over a length of ∼50 nm, and the active device region typically lies below the surface much beyond this range. Here, we report on a novel method for the formation of silver nanoparticles embedded within a silicon crystal through metal gettering from a silver thin film deposited at the surface to nanocavities within the Si created by hydrogen ion implantation. The refractive index of the Ag-nanostructured layer is found to be 3–10% lower or higher than that of silicon for wavelengths below or beyond ∼815–900 nm, respectively. Around this wavelength range, the optical extinction values increase by a factor of 10–100 as opposed to the pure silicon case. Increasing the amount of gettered silver leads to an increased extinction as well as a redshift in wavelength position for the resonance. This resonance is attributed to the surface plasmon excitation of the resultant silver nanoparticles in silicon. Additionally, we show that the profiles for optical constants in silicon can be tailored by varying the position and number of nanocavity layers. Such silicon crystals with embedded metal nanostructures would offer novel functional base structures for applications in silicon photonics, optoelectronics, photovoltaics, and plasmonics

  5. Mechanical, electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

    Science.gov (United States)

    Pal, Hemant; Sharma, Vimal

    2014-11-01

    The mechanical, electrical, and thermal expansion properties of carbon nanotube (CNT)-based silver and silver-palladium (10:1, w/w) alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver-palladium nanocomposite with CNT resulted in increases in the hardness and Young's modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion (CTE). The hardness and Young's modulus of the nanocomposites were increased by 30%-40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver-palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.

  6. Nanoscale Control of Exchange Bias with BiFeO3 Thin Films

    NARCIS (Netherlands)

    Martin, Lane W.; Chu, Ying-Hao; Holcomb, Mikel B.; Huijben, Mark; Yu, Pu; Han, Shu-Jen; Lee, Donkoun; Wang, Shan X.; Ramesh, R.

    2008-01-01

    We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias of Co0.9Fe0.1/BiFeO3 heterostructures. Two distinct types of interactions − an enhancement of the coercive field (exchange enhancement) and an enhancement of the coercive field

  7. Silver Nanoparticles and Graphitic Carbon Through Thermal Decomposition of a Silver/Acetylenedicarboxylic Salt

    Directory of Open Access Journals (Sweden)

    Komninou Philomela

    2009-01-01

    Full Text Available Abstract Spherically shaped silver nanoparticles embedded in a carbon matrix were synthesized by thermal decomposition of a Ag(I/acetylenedicarboxylic acid salt. The silver nanoparticles, which are formed either by pyrolysis at 300 °C in an autoclave or thermolysis in xylene suspension at reflux temperature, are acting catalytically for the formation of graphite layers. Both reactions proceed through in situ reduction of the silver cations and polymerization of the central acetylene triple bonds and the exact temperature of the reaction can be monitored through DTA analysis. Interestingly, the thermal decomposition of this silver salt in xylene partly leads to a minor fraction of quasicrystalline silver, as established by HR-TEM analysis. The graphitic layers covering the silver nanoparticles are clearly seen in HR-TEM images and, furthermore, established by the presence of sp2carbon at the Raman spectrum of both samples.

  8. Friction between silicon and diamond at the nanoscale

    International Nuclear Information System (INIS)

    Bai, Lichun; Srikanth, Narasimalu; Sha, Zhen-Dong; Pei, Qing-Xiang; Wang, Xu; Srolovitz, David J; Zhou, Kun

    2015-01-01

    This work investigates the nanoscale friction between diamond-structure silicon (Si) and diamond via molecular dynamics simulation. The interaction between the interfaces is considered as strong covalent bonds. The effects of load, sliding velocity, temperature and lattice orientation are investigated. Results show that the friction can be divided into two stages: the static friction and the kinetic friction. During the static friction stage, the load, lattice orientation and temperature dramatically affects the friction by changing the elastic limit of Si. Large elastic deformation is induced in the Si block, which eventually leads to the formation of a thin layer of amorphous Si near the Si-diamond interface and thus the beginning of the kinetic friction stage. During the kinetic friction stage, only temperature and velocity have an effect on the friction. The investigation of the microstructural evolution of Si demonstrated that the kinetic friction can be categorized into two modes (stick-slip and smooth sliding) depending on the temperature of the fracture region. (paper)

  9. Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent

    Energy Technology Data Exchange (ETDEWEB)

    Holtz, R D; Souza Filho, A G; Alves, O L [Laboratorio de Quimica do Estado Solido (LQES), Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13081-970, Campinas-SP (Brazil); Brocchi, M; Martins, D [Departamento de Genetica, Evolucao and Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Duran, N, E-mail: rholtz@iqm.unicamp.br, E-mail: agsf@fisica.ufc.br, E-mail: oalves@iqm.unicamp.br [Laboratorio de Quimica Biologica, Instituto de Quimica, Universidade Estadual de Campinas, Campinas-SP (Brazil)

    2010-05-07

    In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

  10. Ablation and formation by plasma of silver metallic films on poly aniline

    International Nuclear Information System (INIS)

    Palacios, J.C.; Olayo, G.; Morales, J.; Cruz, G.J.

    1999-01-01

    This work shows a study about the ablation by plasma conditions in which is possible to form silver layers over polymeric surfaces with the purpose to increase the electric conductivity of the surface. The adhesion between layers formed by polymerization and ablation by plasma respectively is high, with this it is possible to find adequate conditions for getting the polymerization and ablation simultaneously forming with this a thin polymer matrix which would have metallic elements dispersed in its structure. (Author)

  11. Nanoscale Electrochemical Sensing and Processing in Microreactors

    NARCIS (Netherlands)

    Odijk, Mathieu; van den Berg, Albert

    2018-01-01

    In this review, we summarize recent advances in nanoscale electrochemistry, including the use of nanoparticles, carbon nanomaterials, and nanowires. Exciting developments are reported for nanoscale redox cycling devices, which can chemically amplify signal readout. We also discuss promising

  12. The Synthesis of Silver Nanoparticles Produced by Chemical Reduction of Silver Salt Solution

    International Nuclear Information System (INIS)

    Sri Budi Harmani; Dewi Sondari; Agus Haryono

    2008-01-01

    Described in this research are the synthesis of silver nanoparticle produced by chemical reduction of silver salt (silver nitrate AgNO 3 ) solution. As a reducer, sodium citrate (C 6 H 5 O 7 Na 3 ) was used. Preparation of silver colloid is done by using chemical reduction method. In typical experiment 150 ml of 1.10 -3 M AgNO 3 solution was heated with temperature variation such as 90, 100, 110 degree of Celsius. To this solution 15 ml of 1 % trisodium citrate was added into solution drop by drop during heating. During the process, solution was mixed vigorously. Solution was heated until colour's change is evident (pale yellow solution is formed). Then it was removed from the heating element and stirred until cooled to room temperature. Experimental result showed that diameter of silver nanoparticles in colloid solution is about 28.3 nm (Ag colloid, 90 o C); 19.9 nm (Ag colloid, 100 o C)and 26.4 nm (Ag colloid, 110 o C). Characterization of the silver nanoparticle colloid conducted by using UV-Vis Spectroscopy, Particles Size Analyzer (PSA) and Scanning Electron Microscope (SEM) indicate the produced structures of silver nanoparticles. (author)

  13. Synthesis of gold and silver nanoparticles by electron irradiation at 5-15 keV energy

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, S K; Bogle, K A; Dhole, S D; Bhoraskar, V N [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

    2007-04-04

    Thin coatings ({approx}10 {mu}m) made from a mixture of polyvinyl alcohol (PVA) and HAuCl{sub 4} or PVA and AgNO{sub 3} on quartz plates were irradiated with 5-15 keV electrons, at room temperature. The electron energy was varied from coating to coating in the range of 5-15 keV, but electron fluence was kept constant at {approx}10{sup 15} e cm{sup -2}. Samples were characterized by the UV-vis, XRD, SEM and TEM techniques. The plasmon absorption peaks at {approx}511 and {approx}442 nm confirmed the formation of gold and silver nanoparticles in the respective electron-irradiated coatings. The XRD, SEM and TEM measurements reveal that the average size of the particles could be tailored in the range of 130-50 nm for gold and from 150-40 nm for silver by varying the electron energy in the range of 5-15 keV. These particles of gold and silver embedded in the polymer could also be separated by dissolving the coatings in distilled water.

  14. The double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds

    Science.gov (United States)

    Baranov, A. N.; Butsen, A. V.; Ionin, A. A.; Ivanova, A. K.; Kuchmizhak, A. A.; Kudryashov, S. I.; Kudryavtseva, A. D.; Levchenko, A. O.; Rudenko, A. A.; Saraeva, I. N.; Strokov, M. A.; Tcherniega, N. V.; Zayarny, D. A.

    2017-09-01

    Hybrid plasmonic-dielectric nano- and (sub)microparticles exhibit magnetic and electrical dipolar Mie-resonances, which makes them useful as efficient basic elements in surface-enhanced spectroscopy, non-linear light conversion and nanoscale light control. We report the stimulated low-frequency Raman scattering (SLFRS) of a nanosecond ruby laser radiation (central wavelength λ = 694.3 nm (full-width at half-maximum ≈ 0.015 cm-1), gaussian 1/e-intensity pulsewidth τ ≈ 20 ns, TEM00-mode pulse energy Emax ≈ 0.3 J) in nanodiamond (R ≈ 120 nm) hydrosols, induced via optomechanical coherent excitation of fundamental breathing eigen-modes, and the two-fold enhancement of SLFRS in Ag-decorated nanodiamonds, characterized by hybrid dipolar resonances of electrical (silver) and magnetic (diamond) nature. Hybrid metal-dielectric particles were prepared by means of nanosecond IR-laser ablation of solid silver target in diamond hydrosols with consecutive Ag-capping of diamonds, and were characterized by scanning electron microscopy, UV-vis, photoluminescence and energy-dispersive X-ray spectroscopy. Intensities of the SLFR-scattered components and their size-dependent spectral shifts were measured in the highly sensitive stimulated scattering regime, indicating the high (≈ 30%) SLFRS conversion efficiency and the resonant character of the scattering species.

  15. In situ identification of high-performance thin-layer chromatography spots by fourier transform surface-enhanced Raman scattering

    Science.gov (United States)

    Koglin, Eckhardt; Kramer, Hella; Sawatski, Juergen; Lehner, Carolin; Hellman, Janice L.

    1994-01-01

    FT-SERS has been used to identify samples supported on high-performance thin-layer chromatography plates. The TLC plates were sprayed with colloidal silver solutions which resulted in enhancement of the FT-Raman scattering of these biologically and environmentally important compounds.

  16. 21 CFR 310.548 - Drug products containing colloidal silver ingredients or silver salts offered over-the-counter...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Drug products containing colloidal silver... Drug products containing colloidal silver ingredients or silver salts offered over-the-counter (OTC) for the treatment and/or prevention of disease. (a) Colloidal silver ingredients and silver salts have...

  17. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti–Ag and Nb–Ag thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wojcieszak, D., E-mail: damian.wojcieszak@pwr.edu.pl [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, M.; Kaczmarek, D. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, P. [Institute of Experimental Physics, University of Wrocław, Max Born 9, 50-204 Wrocław (Poland); Szponar, B. [Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53–114 Wrocław (Poland); Domaradzki, J. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Kepinski, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland)

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti–Ag and Nb–Ag thin films have been carried out. Ti–Ag and Nb–Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti–Ag and Nb–Ag thin films were nanocrystalline. In the case of Ag–Ti film presence of AgTi{sub 3} and Ag phases was identified, while in the structure of Nb–Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb–Ag thin films was covered with Ag-agglomerates, while Ti–Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h. - Highlights: • Surface and biological properties of Ti–Ag and Nb–Ag thin films were examined. • Ag content was related to sputtering yields and nucleation of Ti and Nb. • For Nb–Ag film the agglomeration of silver at the surface was observed. • Composition and surface topography had an impact on antimicrobial properties. • Fine-grained surface was important in Ag ions release process.

  18. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti–Ag and Nb–Ag thin films

    International Nuclear Information System (INIS)

    Wojcieszak, D.; Mazur, M.; Kaczmarek, D.; Mazur, P.; Szponar, B.; Domaradzki, J.; Kepinski, L.

    2016-01-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti–Ag and Nb–Ag thin films have been carried out. Ti–Ag and Nb–Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti–Ag and Nb–Ag thin films were nanocrystalline. In the case of Ag–Ti film presence of AgTi_3 and Ag phases was identified, while in the structure of Nb–Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb–Ag thin films was covered with Ag-agglomerates, while Ti–Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h. - Highlights: • Surface and biological properties of Ti–Ag and Nb–Ag thin films were examined. • Ag content was related to sputtering yields and nucleation of Ti and Nb. • For Nb–Ag film the agglomeration of silver at the surface was observed. • Composition and surface topography had an impact on antimicrobial properties. • Fine-grained surface was important in Ag ions release process.

  19. Coherent, atomically thin transition-metal dichalcogenide superlattices with engineered strain

    Science.gov (United States)

    Xie, Saien; Tu, Lijie; Han, Yimo; Huang, Lujie; Kang, Kibum; Lao, Ka Un; Poddar, Preeti; Park, Chibeom; Muller, David A.; DiStasio, Robert A.; Park, Jiwoong

    2018-03-01

    Epitaxy forms the basis of modern electronics and optoelectronics. We report coherent atomically thin superlattices in which different transition metal dichalcogenide monolayers—despite large lattice mismatches—are repeated and laterally integrated without dislocations within the monolayer plane. Grown by an omnidirectional epitaxy, these superlattices display fully matched lattice constants across heterointerfaces while maintaining an isotropic lattice structure and triangular symmetry. This strong epitaxial strain is precisely engineered via the nanoscale supercell dimensions, thereby enabling broad tuning of the optical properties and producing photoluminescence peak shifts as large as 250 millielectron volts. We present theoretical models to explain this coherent growth and the energetic interplay governing the ripple formation in these strained monolayers. Such coherent superlattices provide building blocks with targeted functionalities at the atomically thin limit.

  20. Characterization of Electrochemically Generated Silver

    Science.gov (United States)

    Adam, Niklas; Martinez, James; Carrier, Chris

    2014-01-01

    Silver biocide offers a potential advantage over iodine, the current state of the art in US spacecraft disinfection technology, in that silver can be safely consumed by the crew. Low concentrations of silver (Silver does not require hardware to remove it from a water system, and therefore can provide a simpler means for disinfecting water. The Russian segment of the International Space Station has utilized an electrochemically generated silver solution, which is colloidal in nature. To be able to reliably provide a silver biocide to drinking water by electrochemical means would reduce mass required for removing another biocide such as iodine from the water. This would also aid in crew time required to replace iodine removal cartridges. Future long term missions would benefit from electrochemically produced silver as the biocide could be produced on demand and requires only a small concentration to be effective. Since it can also be consumed safely, there is less mass in removal hardware and little consumables required for production. The goal of this project initially is to understand the nature of the electrochemically produced silver, the particle sizes produced by the electrochemical cell and the effect that voltage adjustment has on the particle size. In literature, it has been documented that dissolved oxygen and pH have an effect on the ionization of the electrochemical silver so those parameters would be measured and possibly adjusted to understand their effect on the silver.

  1. Silver carbonate and stability in colloidal silver: A by-product of the electric spark discharge method

    International Nuclear Information System (INIS)

    Tseng, Kuo-Hsiung; Liao, Chih-Yu; Tien, Der-Chi

    2010-01-01

    Many methods of producing colloidal silver (CS) include the introduction of surfactants to improve the suspensivity of the silver particles. The electric spark discharge method (ESDM) which involves pulses of direct current being passed through a silver electrode submerged in deionized water has been shown to successfully produce colloidal silver in a stable suspension without the use of chemical additives. A by-product of the electric spark discharge method, a silver ion compound (AgX), is shown to be the cause of the high suspensivity of the silver nanoparticles (AgNPs). The silver ion compound has been identified as Ag 2 CO 3 using X-ray diffraction, and it has been determined that the Ag 2 CO 3 is formed during the electric spark discharge process through a reaction with atmospheric CO 2 . It has been shown that an Ag 2 CO 3 concentration of 10 ppm or more is sufficient to generate a stable suspension of silver particles. Because of the occurrence of Ag 2 CO 3 , the electric spark discharge method can produce stable colloidal silver.

  2. Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

    Science.gov (United States)

    Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

    2018-04-01

    In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

  3. Relaxation of the silver/silver iodide electrode in aqueous solution

    NARCIS (Netherlands)

    Peverelli, K.J.

    1979-01-01

    The aim of this study is to detect and characterize relaxation processes on silver/silver iodide electrodes in aqueous electrolyte solution. The information obtained is to be used for an estimation of the consequences of similar processes on colloidal AgI

  4. Controlled fabrication of nano-scale double barrier magnetic tunnel junctions using focused ion beam milling method

    International Nuclear Information System (INIS)

    Wei, H.X.; Wang, T.X.; Zeng, Z.M.; Zhang, X.Q.; Zhao, J.; Han, X.F.

    2006-01-01

    The controlled fabrication method for nano-scale double barrier magnetic tunnel junctions (DBMTJs) with the layer structure of Ta(5)/Cu(10)/Ni 79 Fe 21 (5)/Ir 22 Mn 78 (12)/Co 6 Fe 2 B 2 (4)/Al(1) -oxide/Co 6 Fe 2 B 2 (6)/Al (1)-oxide/Co 6 Fe 2 B 2 (4)/Ir 22 Mn 78 (12)/Ni 79 Fe 21 (5)/Ta(5) (thickness unit: nm) was used. This method involved depositing thin multi-layer stacks by sputtering system, and depositing a Pt nano-pillar using a focused ion beam which acted both as a top contact and as an etching mask. The advantages of this process over the traditional process using e-beam and optical lithography in that it involve only few processing steps, e.g. it does not involve any lift-off steps. In order to evaluate the nanofabrication techniques, the DBMTJs with the dimensions of 200 nmx400 nm, 200 nmx200 nm nano-scale were prepared and their R-H, I-V characteristics were measured.

  5. Direct optical imaging of nanoscale internal organization of polymer films

    Science.gov (United States)

    Suran, Swathi; Varma, Manoj

    2018-02-01

    Owing to its sensitivity and precise control at the nanoscale, polyelectrolytes have been immensely used to modify surfaces. Polyelectrolyte multilayers are generally water made and are easy to fabricate on any surface by the layer-by-layer (LbL) self-assembly process due to electrostatic interactions. Polyelectrolyte multilayers or PEMs can be assembled to form ultrathin membranes which can have potential applications in water filtration and desalination [1-3]. Hydration in PEMs is a consequence of both the bulk and surface phenomenon [4-7]. Bulk behavior of polymer membranes are well understood. Several techniques including reflectivity and contact angle measurements were used to measure the hydration in the bulk of polymer membranes [4, 8]. On the other hand their internal organization at the molecular level which can have a profound contribution in the transport mechanism, are not understood well. Previously, we engineered a technique, which we refer to as Bright-field Nanoscopy, which allows nanoscale optical imaging using local heterogeneities in a water-soluble germanium (Ge) thin film ( 25 nm thick) deposited on gold [8]. We use this technique to study the water transport in PEMs. It is understood that the surface charge and outer layers of the PEMs play a significant role in water transport through polymers [9-11]. This well-known `odd-even' effect arising on having different surface termination of the PEMs was optically observed with a spatial resolution unlike any other reported previously [12]. In this communication, we report that on increasing the etchant's concentration, one can control the lateral etching of the Ge film. This allowed the visualization of the nanoscale internal organization in the PEMs. Knowledge of the internal structure would allow one to engineer polymer membranes specific to applications such as drug delivering capsules, ion transport membranes and barriers etc. We also demonstrate a mathematical model involving a surface

  6. Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

    International Nuclear Information System (INIS)

    Afanasiev, Pavel

    2016-01-01

    Silver nitrate hexamethylenetetramine [Ag(NO 3 )·N 4 (CH 2 ) 6 ] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H 2 O 2 electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO 3 )·N 4 (CH 2 ) 6 ] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

  7. Nanoscale technology in biological systems

    CERN Document Server

    Greco, Ralph S; Smith, R Lane

    2004-01-01

    Reviewing recent accomplishments in the field of nanobiology Nanoscale Technology in Biological Systems introduces the application of nanoscale matrices to human biology. It focuses on the applications of nanotechnology fabrication to biomedical devices and discusses new physical methods for cell isolation and manipulation and intracellular communication at the molecular level. It also explores the application of nanobiology to cardiovascular diseases, oncology, transplantation, and a range of related disciplines. This book build a strong background in nanotechnology and nanobiology ideal for

  8. Alternative Silver Production by Environmental Sound Processing of a Sulfo Salt Silver Mineral Found in Bolivia

    Directory of Open Access Journals (Sweden)

    Alexander Birich

    2018-02-01

    Full Text Available Very often, the production of silver causes devastating environmental issues, because of the use of toxic reagents like cyanide and mercury. Due to severe environmental damage caused by humans in the last decades, the social awareness regarding the sustainable production processes is on the rise. Terms like “sustainable” and “green” in product descriptions are becoming more and more popular and producers are forced to satisfy the rising environmental awareness of their customers. Within this work, an alternative environmental sound silver recovery process was developed for a vein type silver ore from Mina Porka, Bolivia. A foregoing characterization of the input material reveals its mineral composition. In the following mineral processing, around 92.9% silver was concentrated by separating 59.5 wt. % of non-silver minerals. Nitric acid leaching of the generated concentrate enabled a silver recovery of up to 98%. The dissolved silver was then separated via copper cementation to generate a metallic silver product of >99% purity. Summarizing all process steps, a silver yield of 87% was achieved in lab scale. A final upscaling trial was conducted to prove the process’ robustness. Within this trial, almost 4 kg of metallic silver with a purity of higher than 99.5 wt. % was produced.

  9. Optical and electrical characterization of AgInS{sub 2} thin films deposited by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Calixto-Rodriguez, M., E-mail: manuela@fis.unam.mx [Instituto de Ciencias Fisicas-Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Martinez, H. [Instituto de Ciencias Fisicas-Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Calixto, M.E. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apartado Postal J-48, 72570, Puebla, Puebla (Mexico); Pena, Y. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba s/n, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Martinez-Escobar, Dalia [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico); Tiburcio-Silver, A. [Instituto Tecnologico de Toluca-SEP, Apartado Postal 20, 52176, Metepec 3, Estado de Mexico (Mexico); Sanchez-Juarez, A. [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico)

    2010-10-25

    Silver indium sulfide (AgInS{sub 2}) thin films have been prepared by spray pyrolysis (SP) technique using silver acetate, indium acetate, and N, N-dimethylthiourea as precursor compounds. Films were deposited onto glass substrates at different substrate temperatures (T{sub s}) and Ag:In:S ratios in the starting solutions. Optical transmission and reflection as well as electrical measurements were performed in order to study the effect of deposition parameters on the optical and electrical properties of AgInS{sub 2} thin films. X-ray diffraction measurements were used to identify the deposited compounds. It was found that different compounds such as AgInS{sub 2}, Ag{sub 2}S, In{sub 2}O{sub 3}, and In{sub 2}S{sub 3} can be grown only by changing the Ag:In:S ratio in the starting solution and T{sub s}. So that, by carefully selecting the deposition parameters, single phase AgInS{sub 2} thin films can be easily grown. Thin films obtained using a molar ratio of Ag:In:S = 1:1:2 and T{sub s} = 400 {sup o}C, have an optical band gap of 1.9 eV and n-type electrical conductivity with a value of 0.3 {Omega}{sup -1} cm{sup -1} in the dark.

  10. Franklin D. Roosevelt, Silver, and China.

    OpenAIRE

    Friedman, Milton

    1992-01-01

    The silver purchase program, initiated by Franklin Roosevelt in late 1933 in response to the economically small but politically potent silver bloc, gave a large short-run subsidy to silver producers at the cost of destroying any long-run monetary role for silver. More important, it imposed severe deflation on China, the only major country still on a silver standard, and forced it off the silver standard and on to a fiat standard, which brought forward in time and increased in severity the sub...

  11. Pinning in high performance MgB{sub 2} thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Prikhna, Tatiana, E-mail: prikhna@mail.ru [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Shapovalov, Andrey [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Eisterer, Michael [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Shaternik, Vladimir [G.V. Kurdyumov Institute for Metal Physics of the National Academy of Sciences of Ukraine, 36 Academician Vernadsky blvd., Kiev, 03680 (Ukraine); Goldacker, Wilfried [Karlsruhe Institute of Technology (KIT), 76344 Eggenstein (Germany); Weber, Harald W. [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Moshchil, Viktor; Kozyrev, Artem; Sverdun, Vladimir [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Boutko, Viktor [Donetsk Institute for Physics and Engineering named after O.O. Galkin of the National Academy of Sciences of Ukraine, R. Luxemburg str.72, Donetsk-114, 83114 (Ukraine); Grechnev, Gennadiy [B. Verkin Institute for Low Temperature Physics of the National Academy of Sciences of Ukraine, 47, Prospekt Nauky, Kharkiv 61103 (Ukraine); Gusev, Alexandr [Donetsk Institute for Physics and Engineering named after O.O. Galkin of the National Academy of Sciences of Ukraine, R. Luxemburg str.72, Donetsk-114, 83114 (Ukraine); Kovylaev, Valeriy; Shaternik, Anton [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine)

    2017-02-15

    Highlights: • Pinning in MgB{sub 2} depends on the Mg-B-O nano-scaled inhomogeneities. • Finer oxygen-enriched inhomogeneities is the reason of the higher J{sub c} in MgB{sub 2} thin films as compared to bulk. • The results of DOS calculations for MgB{sub 2-x}O{sub x} compounds demonstrate that they have metal-like behavior. • Ordered oxygen distribution in MgB{sub 2} (in pairs or zigzags) reduces binding energy. - Abstract: The comparison of nano-crystalline MgB{sub 2} oxygen-containing thin film (140 nm) and highly dense bulk materials showed that the critical current density, J{sub c}, depends on the distribution of Mg-B-O nano-scale inhomogeneities. It has been shown that MgB{sub 2} bulks with high J{sub c} in low (∼10{sup 6} A/cm{sup 2} in 0-1 T at 10 K) and medium magnetic fields contain MgB{sub 0.6-0.8}O{sub 0.8-0.9} nano-inclusions, where δT{sub c} or a combined δT{sub c} (dominant) / δ{sub l} pinning mechanism prevails, while in bulk MgB{sub 2} with high J{sub c} in high magnetic fields (B{sub irr}(18.5 K) = 15 T, B{sub c2}(0 K) = 42.1 T) MgB{sub 1.2-2.7}O{sub 1.8-2.5} nano-layers are present and δ{sub l} pinning prevails. The structure of oxygen-containing films with high J{sub c} in low and high magnetic fields (J{sub c} (0 T) = 1.8 × 10{sup 7} A/cm{sup 2} and J{sub c} (5 T) = 2 × 10{sup 6} A/cm{sup 2} at 10 K) contains very fine oxygen-enriched Mg-B-O inhomogeneities and δ{sub l} pinning is realized. The results of DOS calculations in MgB{sub 2-x}O{sub x} cells for x = 0, 0.125, 0.25, 0.5, 1 demonstrate that all compounds are conductors with metal-like behaviour. In the case of ordered oxygen substitution for boron the binding energy, E{sub b}, does not increase sufficiently as compared with that for MgB{sub 2}, while when oxygen atoms form zigzag chains the calculated E{sub b} is even lower (E{sub b} = −1.15712 Ry).

  12. Controlling the nanoscale morphology of organic films deposited by polyatomic ions

    CERN Document Server

    Hanley, L; Fuoco, E R; Ahu-Akin, F; Wijesundara, M B J; Li, Maozhen; Tikhonov, A; Schlossman, M

    2003-01-01

    Hyperthermal polyatomic ion beams can be used to fabricate thin film nanostructures with controlled morphology. Several experiments are described in which mass-selected and non-mass-selected polyatomic ion beams are used to create nanometer thick films with controlled surface and buried interface morphologies. Fluorocarbon and thiophenic films are grown on silicon wafers and/or polystyrene from 5 to 200 eV C sub 3 F sub 5 sup + or C sub 4 H sub 4 S sup + ions, respectively. X-ray photoelectron spectroscopy, atomic force microscopy, X-ray reflectivity, and scanning electron microscopy are utilized to analyze the morphology and chemistry of these films. Polyatomic ions are found to control film morphology on the nanoscale through variation of the incident ion energy, ion structure and/or substrate.

  13. Creating nanoscale emulsions using condensation.

    Science.gov (United States)

    Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

    2017-11-08

    Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.

  14. Performance enhancement of metal nanowire-based transparent electrodes by electrically driven nanoscale nucleation of metal oxides

    Science.gov (United States)

    Shiau, Yu-Jeng; Chiang, Kai-Ming; Lin, Hao-Wu

    2015-07-01

    Solution-processed silver nanowire (AgNW) electrodes have been considered to be promising materials for next-generation flexible transparent conductive electrodes. Despite the fact that a single AgNW has extremely high conductivities, the high junction resistance between nanowires limits the performance of the AgNW matrix. Therefore, post-treatments are usually required to approach better NW-NW contact. Herein, we report a novel linking method that uses joule heating to accumulate sol-gel ZnO near nanowire junctions. The nanoscale ZnO nucleation successfully restrained the thermal instability of the AgNW under current injection and acted as an efficient tightening medium to realize good NW-NW contacts. A low process temperature (PET and PEN, feasible. The optimized AgNW transparent conductive electrodes (TCE) fabricated using this promising linking method exhibited a low sheet resistance (13 Ω sq-1), a high transmission (92% at 550 nm), a high figure of merit (FOM; up to σDC/σOp = 340) and can be applied to wide range of next-generation flexible optoelectronic devices.Solution-processed silver nanowire (AgNW) electrodes have been considered to be promising materials for next-generation flexible transparent conductive electrodes. Despite the fact that a single AgNW has extremely high conductivities, the high junction resistance between nanowires limits the performance of the AgNW matrix. Therefore, post-treatments are usually required to approach better NW-NW contact. Herein, we report a novel linking method that uses joule heating to accumulate sol-gel ZnO near nanowire junctions. The nanoscale ZnO nucleation successfully restrained the thermal instability of the AgNW under current injection and acted as an efficient tightening medium to realize good NW-NW contacts. A low process temperature (PET and PEN, feasible. The optimized AgNW transparent conductive electrodes (TCE) fabricated using this promising linking method exhibited a low sheet resistance (13 Ω sq

  15. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Guowen, E-mail: gding@intermolecular.com; Clavero, César; Schweigert, Daniel; Le, Minh [Intermolecular, Inc., 3011 North First Street, San Jose, CA 95134 (United States)

    2015-11-15

    The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  16. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

    Science.gov (United States)

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-04-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

  17. Micron-scale channel formation by the release and bond-back of pre-stressed thin films : A finite element analysis

    NARCIS (Netherlands)

    Annabattula, R. K.; Huck, W. T. S.; Onck, P. R.

    Buckling of thin films on a rigid substrate during use or fabrication is a well-known but unwanted phenomenon. However, this phenomenon can also be exploited to generate well-controlled patterns at the micro and nano-scale. These patterned surfaces find various technological applications such as

  18. The influence of silver-ion doping using ion implantation on the luminescence properties of Er–Yb silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stanek, S., E-mail: stanislav.stanek@vscht.cz [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Nekvindova, P.; Svecova, B.; Vytykacova, S.; Mika, M. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Oswald, J. [Institute of Physics, Academy of Science of the Czech Republic, Cukrovarnicka 10/112, 162 00 Prague (Czech Republic); Mackova, A.; Malinsky, P. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske mladeze 8, 40096 Usti nad Labem (Czech Republic); Spirkova, J. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic)

    2016-03-15

    A set of zinc-silicate glasses with different ratios of erbium and ytterbium was fabricated. To achieve Ag-rich thin films in a sub-surface layer, ion-implantation technique at an energy of 1.2 MeV and 1.7 MeV with a fluence of 1 × 10{sup 16} cm{sup −2} was used. Post-implantation annealing was also applied. Changes in the spectroscopic and lasing properties of erbium ions as a function of implantation fluence of silver were studied with the aim to assess the positive effect of silver as a sensitiser of erbium luminescence. Therefore, absorption spectra in the visible range as well as luminescence spectra in the near-infrared range were measured and partially also the {sup 4}I{sub 11/2}–{sup 4}I{sub 15/2} transition of the erbium ion was studied. The results showed that silver positively influenced luminescence intensity at 1530 nm by increasing it almost three times. The biggest increase was achieved in glass with the highest concentration of erbium. Luminescence lifetime was not significantly influenced by the presence of silver and still remained around 10 ms.

  19. Thermal decomposition process of silver behenate

    International Nuclear Information System (INIS)

    Liu Xianhao; Lu Shuxia; Zhang Jingchang; Cao Weiliang

    2006-01-01

    The thermal decomposition processes of silver behenate have been studied by infrared spectroscopy (IR), X-ray diffraction (XRD), combined thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS), transmission electron microscopy (TEM) and UV-vis spectroscopy. The TG-DTA and the higher temperature IR and XRD measurements indicated that complicated structural changes took place while heating silver behenate, but there were two distinct thermal transitions. During the first transition at 138 deg. C, the alkyl chains of silver behenate were transformed from an ordered into a disordered state. During the second transition at about 231 deg. C, a structural change took place for silver behenate, which was the decomposition of silver behenate. The major products of the thermal decomposition of silver behenate were metallic silver and behenic acid. Upon heating up to 500 deg. C, the final product of the thermal decomposition was metallic silver. The combined TG-MS analysis showed that the gas products of the thermal decomposition of silver behenate were carbon dioxide, water, hydrogen, acetylene and some small molecule alkenes. TEM and UV-vis spectroscopy were used to investigate the process of the formation and growth of metallic silver nanoparticles

  20. Nanoscale thermal transport: Theoretical method and application

    Science.gov (United States)

    Zeng, Yu-Jia; Liu, Yue-Yang; Zhou, Wu-Xing; Chen, Ke-Qiu

    2018-03-01

    With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very important issue. In addition, the heat generated by the electronic devices mostly diffuses to the air in the form of waste heat, which makes the thermoelectric energy conversion also an important issue for nowadays. In recent years, the thermal transport properties in nanoscale systems have attracted increasing attention in both experiments and theoretical calculations. In this review, we will discuss various theoretical simulation methods for investigating thermal transport properties and take a glance at several interesting thermal transport phenomena in nanoscale systems. Our emphasizes will lie on the advantage and limitation of calculational method, and the application of nanoscale thermal transport and thermoelectric property. Project supported by the Nation Key Research and Development Program of China (Grant No. 2017YFB0701602) and the National Natural Science Foundation of China (Grant No. 11674092).

  1. Large-scale roll-to-roll photonic sintering of flexo printed silver nanoparticle electrodes

    DEFF Research Database (Denmark)

    Hösel, Markus; Krebs, Frederik C

    2012-01-01

    In this report we employ static and roll-to-roll (R2R) photonic sintering processes on flexo printed silver nanoparticle-based electrode structures with a heat-sensitive 60 mm thin barrier foil as a substrate. We use large area electrode structures to visualize the increased optical footprint...... as the nanoparticles are already sintered. The advantage of single exposure is the ability to produce higher R2R processing speeds without overlapping, which is shown in the form of theoretical calculations....

  2. Inkjet-printed transparent nanowire thin film features for UV photodetectors

    KAUST Repository

    Chen, Shih Pin

    2015-01-01

    In this study, a simple and effective direct printing method was developed to print patterned nanowire thin films for UV detection. Inks containing silver or titanium dioxide (TiO2) nanowires were first formulated adequately to form stable suspension for inkjet printing applications. Sedimentation tests were also carried out to characterize the terminal velocity and dispersion stability of nanowires to avoid potential nozzle clogging problems. The well-dispersed silver nanowire ink was then inkjet printed on PET films to form patterned electrodes. Above the electrodes, another layer of TiO2 nanowires was also printed to create a highly transparent photodetector with >80% visible transmittance. The printed photodetector showed a fairly low dark current of 10-12-10-14 A with a high on/off ratio of 2000 to UV radiation. Under a bias voltage of 2 V, the detector showed fast responses to UV illumination with a rise time of 0.4 s and a recovery time of 0.1 s. More photo currents can also be collected with a larger printed electrode area. In summary, this study shows the feasibility of applying inkjet printing technology to create nanowire thin films with specific patterns, and can be further employed for photoelectric applications. © The Royal Society of Chemistry 2015.

  3. Effect of preconditioning on silver leaching and bromide removal properties of silver-impregnated activated carbon (SIAC).

    Science.gov (United States)

    Rajaeian, Babak; Allard, Sébastien; Joll, Cynthia; Heitz, Anna

    2018-07-01

    Silver impregnated activated carbon (SIAC) has been found to be effective in mitigating the formation of brominated-disinfection by products during drinking water treatment. However, there are still uncertainties regarding its silver leaching properties, and strategies for the prevention of silver leaching have remained elusive. This study focused on the evaluation of one type of commercially available SIAC for its ability to remove bromide while minimising silver leaching from the material. Both synthetic and real water matrices were tested. Depending on solution pH, it was found that changing the surface charge properties of SIAC, as measured by the point of zero charge pH, can result in additional bromide removal while minimising the extent of silver leaching. To better understand the mechanism of silver leaching from the SIAC, eight preconditioning environments, i.e. variable pH and ionic strength were tested for a fixed amount of SIAC and two preconditioning environments were selected for a more detailed investigation. Experiments carried out in synthetic water showed that preconditioning at pH 10.4 did not deteriorate the capacity of SIAC to remove bromide, but significantly decreased the release of silver in the form of ionic silver (Ag + ), silver bromide (AgBr) and silver chloride (AgCl) from 40% for the pristine to 3% for the treated SIAC. This was confirmed using a groundwater sample. These results suggest that preconditioned SIAC has the potential to be an effective method for bromide removal with minimised silver leaching in a long-term field application for drinking water production. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Influence of silver nanoparticles on relaxation processes and efficiency of dipole – dipole energy transfer between dye molecules in polymethylmethacrylate films

    Energy Technology Data Exchange (ETDEWEB)

    Bryukhanov, V V; Borkunov, R Yu; Tsarkov, M V [Immanuel Kant Baltic Federal University, Kaliningrad (Russian Federation); Konstantinova, E I; Slezhkin, V A [Kaliningrad State Technical University, Kaliningrad (Russian Federation)

    2015-10-31

    The fluorescence and phosphorescence of dyes in thin polymethylmethacrylate (PMMA) films in the presence of ablated silver nanoparticles has been investigated in a wide temperature range by methods of femtosecond and picosecond laser photoexcitation. The fluorescence and phosphorescence times, as well as spectral and kinetic characteristics of rhodamine 6G (R6G) molecules in PMMA films are measured in a temperature range of 80 – 330 K. The temperature quenching activation energy of the fluorescence of R6G molecules in the presence of ablated silver nanoparticles is found. The vibrational relaxation rate of R6G in PMMA films is estimated, the efficiency of the dipole – dipole electron energy transfer between R6G and brilliant green molecules (enhanced by plasmonic interaction with ablated silver nanoparticles) is analysed, and the constants of this energy transfer are determined. (nanophotonics)

  5. Influence of silver nanoparticles on relaxation processes and efficiency of dipole – dipole energy transfer between dye molecules in polymethylmethacrylate films

    International Nuclear Information System (INIS)

    Bryukhanov, V V; Borkunov, R Yu; Tsarkov, M V; Konstantinova, E I; Slezhkin, V A

    2015-01-01

    The fluorescence and phosphorescence of dyes in thin polymethylmethacrylate (PMMA) films in the presence of ablated silver nanoparticles has been investigated in a wide temperature range by methods of femtosecond and picosecond laser photoexcitation. The fluorescence and phosphorescence times, as well as spectral and kinetic characteristics of rhodamine 6G (R6G) molecules in PMMA films are measured in a temperature range of 80 – 330 K. The temperature quenching activation energy of the fluorescence of R6G molecules in the presence of ablated silver nanoparticles is found. The vibrational relaxation rate of R6G in PMMA films is estimated, the efficiency of the dipole – dipole electron energy transfer between R6G and brilliant green molecules (enhanced by plasmonic interaction with ablated silver nanoparticles) is analysed, and the constants of this energy transfer are determined. (nanophotonics)

  6. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  7. One-Pot Silver Nanoring Synthesis

    Science.gov (United States)

    Drogat, Nicolas; Granet, Robert; Sol, Vincent; Krausz, Pierre

    2010-03-01

    Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV-vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

  8. Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO 3

    KAUST Repository

    Li, Yangyang

    2016-06-27

    Metal/oxide interfaces are ubiquitous in a wide range of applications such as electronics, photovoltaics, memories, catalysis, and sensors. However, there have been few investigations dedicated to the nanoscale structural and chemical characteristics of these buried interfaces. In this work, the metal/oxide interface between Ti and SrTiO3 (STO) is examined as a prototypical system using high-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. An atomic-thin Ti2O3-like layer at the Ti/STO interface prepared at room temperature is discovered, and first-principles calculations predict a metallic band structure of this 2D electron system. As a universal feature of such interfaces prepared at different temperatures, near the interface nanoscale oxygen-deficient domains and continuous modulation of Ti oxidation states are found. Overall, these results directly reveal complex chemical and valence evolutions at the metal/oxide interfaces, providing microscopic insights on such heterostructures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  9. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Directory of Open Access Journals (Sweden)

    Guowen Ding

    2015-11-01

    Full Text Available The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C, with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  10. Propagation of bulk longitudinal waves in thin films using laser ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yun Young [Dept. of Mechanical Engineering, Dong-eui University, Busan (Korea, Republic of)

    2016-08-15

    This paper presents the investigation of the propagation behavior of bulk longitudinal waves generated by an ultrafast laser system in thin films. A train of femtosecond laser pulses was focused onto the surface of a 150-nm thick metallic (chromium or aluminum) film on a silicon substrate to excite elastic waves, and the change in thermoreflectance at the spot was monitored to detect the arrival of echoes from the film/substrate interface. The experimental results show that the film material characteristics such as the wave velocity and Young's modulus can be evaluated through curve-fitting in numerical solutions. The material properties of nanoscale thin films are difficult to measure using conventional techniques. Therefore, this research provides an effective method for the nondestructive characterization of nanomaterials.

  11. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Science.gov (United States)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. PMID:21451238

  12. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali; Jabbari, Esmaiel

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  13. Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranes.

    Science.gov (United States)

    Wang, Luda; Boutilier, Michael S H; Kidambi, Piran R; Jang, Doojoon; Hadjiconstantinou, Nicolas G; Karnik, Rohit

    2017-06-06

    Graphene and other two-dimensional materials offer a new approach to controlling mass transport at the nanoscale. These materials can sustain nanoscale pores in their rigid lattices and due to their minimum possible material thickness, high mechanical strength and chemical robustness, they could be used to address persistent challenges in membrane separations. Here we discuss theoretical and experimental developments in the emerging field of nanoporous atomically thin membranes, focusing on the fundamental mechanisms of gas- and liquid-phase transport, membrane fabrication techniques and advances towards practical application. We highlight potential functional characteristics of the membranes and discuss applications where they are expected to offer advantages. Finally, we outline the major scientific questions and technological challenges that need to be addressed to bridge the gap from theoretical simulations and proof-of-concept experiments to real-world applications.

  14. Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranes

    Science.gov (United States)

    Wang, Luda; Boutilier, Michael S. H.; Kidambi, Piran R.; Jang, Doojoon; Hadjiconstantinou, Nicolas G.; Karnik, Rohit

    2017-06-01

    Graphene and other two-dimensional materials offer a new approach to controlling mass transport at the nanoscale. These materials can sustain nanoscale pores in their rigid lattices and due to their minimum possible material thickness, high mechanical strength and chemical robustness, they could be used to address persistent challenges in membrane separations. Here we discuss theoretical and experimental developments in the emerging field of nanoporous atomically thin membranes, focusing on the fundamental mechanisms of gas- and liquid-phase transport, membrane fabrication techniques and advances towards practical application. We highlight potential functional characteristics of the membranes and discuss applications where they are expected to offer advantages. Finally, we outline the major scientific questions and technological challenges that need to be addressed to bridge the gap from theoretical simulations and proof-of-concept experiments to real-world applications.

  15. One-Pot Silver Nanoring Synthesis

    Directory of Open Access Journals (Sweden)

    Drogat Nicolas

    2009-01-01

    Full Text Available Abstract Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

  16. Silver diamine fluoride: a caries "silver-fluoride bullet".

    Science.gov (United States)

    Rosenblatt, A; Stamford, T C M; Niederman, R

    2009-02-01

    The antimicrobial use of silver compounds pivots on the 100-year-old application of silver nitrate, silver foil, and silver sutures for the prevention and treatment of ocular, surgical, and dental infections. Ag(+) kills pathogenic organisms at concentrations of linings, water purification systems, hospital gowns, and caries prevention. To distill the current best evidence relative to caries, this systematic review asked: Will silver diamine fluoride (SDF) more effectively prevent caries than fluoride varnish? A five-database search, reference review, and hand search identified 99 human clinical trials in three languages published between 1966 and 2006. Dual review for controlled clinical trials with the patient as the unit of observation, and excluding cross-sectional, animal, in vitro studies, and opinions, identified 2 studies meeting the inclusion criteria. The trials indicated that SDF's lowest prevented fractions for caries arrest and caries prevention were 96.1% and 70.3%, respectively. In contrast, fluoride varnish's highest prevented fractions for caries arrest and caries prevention were 21.3% and 55.7%, respectively. Similarly, SDF's highest numbers needed to treat for caries arrest and caries prevention were 0.8 (95% CI=0.5-1.0) and 0.9 (95% CI=0.4-1.1), respectively. For fluoride varnish, the lowest numbers needed to treat for caries arrest and prevention were 3.7 (95% CI=3.4-3.9) and 1.1 (95% CI=0.7-1.4), respectively. Adverse events were monitored, with no significant differences between control and experimental groups. These promising results suggest that SDF is more effective than fluoride varnish, and may be a valuable caries-preventive intervention. As well, the availability of a safe, effective, efficient, and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine's criteria for 21st century medical care.

  17. The application of LA-ICP-MS in the examination of the thin plating layers found in late Roman coins

    Energy Technology Data Exchange (ETDEWEB)

    Vlachou-Mogire, C. [Numismatic Museum, 12 El. Venizelou Avenue, 106 71 Athens (Greece)], E-mail: vlachou_mogire@yahoo.co.uk; Stern, B.; McDonnell, J.G. [Department of Archaeological Sciences, University of Bradford, Bradford BD7 1RD (United Kingdom)

    2007-12-15

    During the late Roman period the production of complex copper alloy (Cu-Sn-Pb-Ag) coins with a silvered surface, became common practice. Previous analyses of these coins did not solve key technological issues and in particular, the silvering process. Two methods have been suggested for the production of the thin plating layers in late Roman coins the dipping in molten silver chloride and the use of silvering pastes. However, there are questions about their use. More recent research showed that hot-dipping methods, such as the dipping in molten silver chloride, were not really suitable for mass production. Also, the earliest references to the use of silvering pastes dated to 17th century AD. A review of ancient sources and historic literature indicated silver amalgam plating as the possible method for the production of the plating in late Roman coins. Results derived from non-destructive LA-ICP-MS analysis have demonstrated, for the first time, the presence of Hg in the surface layers of these coins. The optimization of the method and the factors influenced the analyses results, are discussed. The examination of the coins by means of EPMA confirmed the ICP-MS results. The introduction of a new technique for the examination of plating layers, helped in the identification of amalgam silvering as the method used in the production of the coins.

  18. Investigation of interaction between silver oxide electrode and separator hydrated cellulose film in silver-cadmium accumulators

    International Nuclear Information System (INIS)

    Molotkova, E.N.; Yarochkina, E.N.

    1975-01-01

    Oxidation-reduction interaction of the oxysilver electrode with hydrocellulose film during storing charged silver-cadmium accumulators. It was demonstrated that accumulator electric characteristics durinq storing are linearly depending on the capacity of this hydrocellulose film to interact with silver oxide: the more silver is absorbed by film the quicker is the decreasing of the electromotive force and capacity of the accumulators. Preservation of the silver electrode capacity in the silver-cadmium accumulators is determined first of all by hydrocellulose separation film properties and especially by film layer adjacent to positive electrode. The more inert film layer is, regarding to silver oxide in the electrolite, the slower is dissolution of the electrode and also decompousing speed of AgO, the longer is the accumulator preservation time

  19. Neuromorphic computing with nanoscale spintronic oscillators.

    Science.gov (United States)

    Torrejon, Jacob; Riou, Mathieu; Araujo, Flavio Abreu; Tsunegi, Sumito; Khalsa, Guru; Querlioz, Damien; Bortolotti, Paolo; Cros, Vincent; Yakushiji, Kay; Fukushima, Akio; Kubota, Hitoshi; Yuasa, Shinji; Stiles, Mark D; Grollier, Julie

    2017-07-26

    Neurons in the brain behave as nonlinear oscillators, which develop rhythmic activity and interact to process information. Taking inspiration from this behaviour to realize high-density, low-power neuromorphic computing will require very large numbers of nanoscale nonlinear oscillators. A simple estimation indicates that to fit 10 8 oscillators organized in a two-dimensional array inside a chip the size of a thumb, the lateral dimension of each oscillator must be smaller than one micrometre. However, nanoscale devices tend to be noisy and to lack the stability that is required to process data in a reliable way. For this reason, despite multiple theoretical proposals and several candidates, including memristive and superconducting oscillators, a proof of concept of neuromorphic computing using nanoscale oscillators has yet to be demonstrated. Here we show experimentally that a nanoscale spintronic oscillator (a magnetic tunnel junction) can be used to achieve spoken-digit recognition with an accuracy similar to that of state-of-the-art neural networks. We also determine the regime of magnetization dynamics that leads to the greatest performance. These results, combined with the ability of the spintronic oscillators to interact with each other, and their long lifetime and low energy consumption, open up a path to fast, parallel, on-chip computation based on networks of oscillators.

  20. Traceable nanoscale measurement at NML-SIRIM

    International Nuclear Information System (INIS)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-01-01

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  1. Traceable nanoscale measurement at NML-SIRIM

    Science.gov (United States)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-06-01

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  2. Traceable nanoscale measurement at NML-SIRIM

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Ahmad M.; Abdul Hapip, A. I. [National Metrology Laboratory SIRIM Berhad (NML-SIRIM), Lot PT 4803, Bandar Baru Salak Tinggi, 43900 Sepang (Malaysia)

    2012-06-29

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  3. Low-silver radiographic detectors

    International Nuclear Information System (INIS)

    Troitskii, V.A.; Novikov, I.A.; Nikitin, V.F.; Krasnyi-Admoni, L.V.; Valevich, M.I.; Belyi, N.G.; Grom, V.S.

    1988-01-01

    X-ray films and screens with low silver content for use in weld radiography are reviewed and tested. Properties examined include image graininess, brightness, and sensitivity to x radiation. Results are given for radiography of steel 08Kh18N10T, St20, AMG-6, copper, and titanium welds. Processing techniques for low-silver films are discussed. It is established that films and screens containing little silver can replace many x-ray films containing much more silver. Monitoring methods were developed for the new materials to cover items in classes 3-7 on GOST 23075-78 when used with equipment of RUP-150/300-10 type or classes 4-7 with pulsed x-ray equipment

  4. The influence of tertiary butyl hydrazine as a co-reactant on the atomic layer deposition of silver

    Energy Technology Data Exchange (ETDEWEB)

    Golrokhi, Zahra; Marshall, Paul A.; Romani, Simon [Centre for Materials and Structures, School of Engineering,The University of Liverpool, Liverpool L69 3GH (United Kingdom); Rushworth, Simon [EpiValence, The Wilton Centre, Redcar, Cleveland, TS10 4RF (United Kingdom); Chalker, Paul R. [Centre for Materials and Structures, School of Engineering,The University of Liverpool, Liverpool L69 3GH (United Kingdom); Potter, Richard J., E-mail: rjpott@liverpool.ac.uk [Centre for Materials and Structures, School of Engineering,The University of Liverpool, Liverpool L69 3GH (United Kingdom)

    2017-03-31

    Highlights: • We demonstrate metallic silver growth by direct liquid injection thermal ALD. • A substituted hydrazine is used as a powerful reducing agent for the first time. • The hydrazine extends the ALD temperature window compared with alcohol. • Hydrazine promotes a more planar growth mode compared to alcohol. • Film adhesion is improved using hydrazine compared with alcohol. - Abstract: Ultra-thin conformal silver films are the focus of development for applications such as anti-microbial surfaces, optical components and electronic devices. In this study, metallic silver films have been deposited using direct liquid injection thermal atomic layer deposition (ALD) using (hfac)Ag(1,5-COD) ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) as the metal source and tertiary butyl hydrazine (TBH) as a co-reactant. The process provides a 23 °C wide ‘self-limiting’ ALD temperature window between 105 and 128 °C, which is significantly wider than is achievable using alcohol as a co-reactant. A mass deposition rate of ∼20 ng/cm{sup 2}/cycle (∼0.18 Å/cycle) is observed under self-limiting growth conditions. The resulting films are crystalline metallic silver with a near planar film-like morphology which are electrically conductive. By extending the temperature range of the ALD window by the use of TBH as a co-reactant, it is envisaged that the process will be exploitable in a range of new low temperature applications.

  5. One-pot silver nanoring synthesis.

    OpenAIRE

    Drogat , Nicolas; Granet , Robert; Sol , Vincent; Krausz , Pierre

    2009-01-01

    Abstract Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH...

  6. Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, Pavel, E-mail: pavel.afanasiev@ircelyon.univ-lyon.fr

    2016-07-15

    Silver nitrate hexamethylenetetramine [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H{sub 2}O{sub 2} electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

  7. Simultaneous reflectometry and interferometry for measuring thin-film thickness and curvature

    Science.gov (United States)

    Arends, A. A.; Germain, T. M.; Owens, J. F.; Putnam, S. A.

    2018-05-01

    A coupled reflectometer-interferometer apparatus is described for thin-film thickness and curvature characterization in the three-phase contact line region of evaporating fluids. Validation reflectometry studies are provided for Au, Ge, and Si substrates and thin-film coatings of SiO2 and hydrogel/Ti/SiO2. For interferometry, liquid/air and solid/air interferences are studied, where the solid/air samples consisted of glass/air/glass wedges, cylindrical lenses, and molded polydimethylsiloxane lenses. The liquid/air studies are based on steady-state evaporation experiments of water and isooctane on Si and SiO2/Ti/SiO2 wafers. The liquid thin-films facilitate characterization of both (i) the nano-scale thickness of the absorbed fluid layer and (ii) the macro-scale liquid meniscus thickness, curvature, and curvature gradient profiles. For our validation studies with commercial lenses, the apparatus is shown to measure thickness profiles within 4.1%-10.8% error.

  8. Selective recovery of silver from waste low-temperature co-fired ceramic and valorization through silver nanoparticle synthesis.

    Science.gov (United States)

    Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho

    2017-11-01

    Considering the value of silver metal and silver nanoparticles, the waste generated during manufacturing of low temperature co-fired ceramic (LTCC) were recycled through the simple yet cost effective process by chemical-metallurgy. Followed by leaching optimization, silver was selectively recovered through precipitation. The precipitated silver chloride was valorized though silver nanoparticle synthesis by a simple one-pot greener synthesis route. Through leaching-precipitation optimization, quantitative selective recovery of silver chloride was achieved, followed by homogeneous pure silver nanoparticle about 100nm size were synthesized. The reported recycling process is a simple process, versatile, easy to implement, requires minimum facilities and no specialty chemicals, through which semiconductor manufacturing industry can treat the waste generated during manufacturing of LTCC and reutilize the valorized silver nanoparticles in manufacturing in a close loop process. Our reported process can address issues like; (i) waste disposal, as well as value-added silver recovery, (ii) brings back the material to production stream and address the circular economy, and (iii) can be part of lower the futuristic carbon economy and cradle-to-cradle technology management, simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Silver-Palladium Surfaces Inhibit Biofilm Formation

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Schroll, Casper; Hilbert, Lisbeth Rischel

    2009-01-01

    Undesired biofilm formation is a major concern in many areas. In the present study, we investigated biofilm-inhibiting properties of a silver-palladium surface that kills bacteria by generating microelectric fields and electrochemical redox processes. For evaluation of the biofilm inhibition...... efficacy and study of the biofilm inhibition mechanism, the silver-sensitive Escherichia coli J53 and the silver-resistant E. coli J53[pMG101] strains were used as model organisms, and batch and flow chamber setups were used as model systems. In the case of the silver-sensitive strain, the silver......-palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silver-palladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under...

  10. Positron Annihilation Spectroscopy as a Novel Interfacial Probe for Thin Polymeric Films and Nano-Composites

    Science.gov (United States)

    Awad, Somia; Chen, Hongmin; Maina, Grace; Lee, L. James; Gu, Xiaohong; Jean, Y. C.

    2010-03-01

    Positron annihilation spectroscopy (PAS) has been developed as a novel probe to characterize the sub-nanometer defect, free volume, profile from the surface, interfaces, and to the bulk in polymeric materials when a variable mono-energy slow positron beam is used. Free-volume hole sizes, fractions, and distributions are measurable as a function of depth at the high precision. PAS has been successfully used to study the interfacial properties of polymeric nanocomposites at different chemical bonding. In nano-scale thin polymeric films, such as in PS/SiO2, and PU/ZnO, significant variations of Tg as a function of depth and of wt% oxide are observed. Variations of Tg are dependent on strong or weak interactions between polymers and nano-scale oxides surfaces.

  11. Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures

    Directory of Open Access Journals (Sweden)

    Mao-Kuo Wei

    2010-04-01

    Full Text Available In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode.

  12. High-performance electrically conductive silver paste prepared by silver-containing precursor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jianguo; Cao, Yu; Li, Xiangyou; Wang, Xiaoye; Zeng, Xiaoyan [Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Wuhan (China)

    2010-09-15

    A high-performance electrically conductive silver paste with no solid particles before drying and/or sintering is developed, in which silver-containing precursor is employed as conductive functional phase. Thermogravimetry analysis, volume electrical resistivity tests and sintering experiments show that the paste with about 14 wt.% silver pristine content is able to achieve the volume electrical resistivity of (2-3) x 10{sup -5} {omega} cm after it is sintered at 220 C. A micro-pen direct-writing process indicates that it is very suitable for the fabrication of high-resolution (25 {mu}m) and high-integration devices and apparatus. (orig.)

  13. The Architectural Designs of a Nanoscale Computing Model

    Directory of Open Access Journals (Sweden)

    Mary M. Eshaghian-Wilner

    2004-08-01

    Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.

  14. The silver lining: towards the responsible and limited usage of silver.

    Science.gov (United States)

    Naik, K; Kowshik, M

    2017-11-01

    Silver has attracted a lot of attention as a powerful, broad spectrum and natural antimicrobial agent since the ancient times because of its nontoxic nature to the human body at low concentrations. It has been used in treatment of various infections and ulcers, storage of water and prevention of bacterial growth on the surfaces and within materials. However, there are numerous medical and health benefits of colloidal or nanosilver apart from its microbicidal ability which as yet has not been fully embraced by the medical community. These include antiplatelet activity, antioxidant effect, anticancer activity, wound healing and bone regeneration, enhancement of immunity, and increase in antibiotic efficiency. Additionally silver also provides protection against alcohol toxicity, upper respiratory tract infections and stomach ailments. Although nanosilver has been proposed for various topical applications, its usage by ingestion and inhalation remains controversial due to the lack of detailed and precise toxicity information. These beneficial properties of silver can be utilized by using silver at very low concentrations which are not harmful to the human body and environment. The following review discusses the diverse medical applications of silver and further recommends human clinical studies for its in vivo usage. #x00A9; 2017 The Society for Applied Microbiology.

  15. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-Kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-Chen; Lin, Shih-Guei; Suganuma, Katsuaki

    2016-10-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings.

  16. Atomic force imaging microscopy investigation of the interaction of ultraviolet radiation with collagen thin films

    Science.gov (United States)

    Stylianou, A.; Yova, D.; Alexandratou, E.; Petri, A.

    2013-02-01

    Collagen is the major fibrous protein in the extracellular matrix and consists a significant component of skin, bone, cartilage and tendon. Due to its unique properties, it has been widely used as scaffold or culture substrate for tissue regeneration or/and cell-substrate interaction studies. The ultraviolet light-collagen interaction investigations are crucial for the improvement of many applications such as that of the UV irradiation in the field of biomaterials, as sterilizing and photo-cross-linking method. The aim of this paper was to investigate the mechanisms of UV-collagen interactions by developing a collagen-based, well characterized, surface with controlled topography of collagen thin films in the nanoscale range. The methodology was to quantify the collagen surface modification induced on ultraviolet radiation and correlate it with changes induced in cells. Surface nanoscale characterization was performed by Atomic Force Microscopy (AFM) which is a powerful tool and offers quantitative and qualitative information with a non-destructive manner. In order to investigate cells behavior, the irradiated films were used for in vitro cultivation of human skin fibroblasts and the cells morphology, migration and alignment were assessed with fluorescence microscopy imaging and image processing methods. The clarification of the effects of UV light on collagen thin films and the way of cells behavior to the different modifications that UV induced to the collagen-based surfaces will contribute to the better understanding of cell-matrix interactions in the nanoscale and will assist the appropriate use of UV light for developing biomaterials.

  17. Electron beam physical vapor deposition of thin ruby films for remote temperature sensing

    International Nuclear Information System (INIS)

    Li Wei; Coppens, Zachary J.; Greg Walker, D.; Valentine, Jason G.

    2013-01-01

    Thermographic phosphors (TGPs) possessing temperature-dependent photoluminescence properties have a wide range of uses in thermometry due to their remote access and large temperature sensitivity range. However, in most cases, phosphors are synthesized in powder form, which prevents their use in high resolution micro and nanoscale thermal microscopy. In the present study, we investigate the use of electron beam physical vapor deposition to fabricate thin films of chromium-doped aluminum oxide (Cr-Al 2 O 3 , ruby) thermographic phosphors. Although as-deposited films were amorphous and exhibited weak photoluminescence, the films regained the stoichiometry and α-Al 2 O 3 crystal structure of the combustion synthesized source powder after thermal annealing. As a consequence, the annealed films exhibit both strong photoluminescence and a temperature-dependent lifetime that decreases from 2.9 ms at 298 K to 2.1 ms at 370 K. Ruby films were also deposited on multiple substrates. To ensure a continuous film with smooth surface morphology and strong photoluminescence, we use a sapphire substrate, which is thermal expansion coefficient and lattice matched to the film. These thin ruby films can potentially be used as remote temperature sensors for probing the local temperatures of micro and nanoscale structures.

  18. Shell and membrane theories in mechanics and biology from macro- to nanoscale structures

    CERN Document Server

    Mikhasev, Gennadi

    2015-01-01

    This book presents the latest results related to shells  characterize and design shells, plates, membranes and other thin-walled structures, a multidisciplinary approach from macro- to nanoscale is required which involves the classical disciplines of mechanical/civil/materials engineering (design, analysis, and properties) and physics/biology/medicine among others. The book contains contributions of a meeting of specialists (mechanical engineers, mathematicians, physicists and others) in such areas as classical and non-classical shell theories. New trends with respect to applications in mechanical, civil and aero-space engineering, as well as in new branches like medicine and biology are presented which demand improvements of the theoretical foundations of these theories and a deeper understanding of the material behavior used in such structures.

  19. Direct observation of the formation of silver precipitations by means of electron diffraction

    International Nuclear Information System (INIS)

    Benz, V.; Ostwald, R.; Weil, K.G.

    1976-01-01

    Thin films (20-1,000 A) of copper (I)-, silver, and lead(II)-halides were prepared by evaporation onto silver (III), gold (III), and PbTe (III)-surfaces. These films were irradiated in vacuo with 40 kV-electrons, in some cases also with the light of a Xenon-lamp. At the same time the diffraction pattern, produced by the electron beam at glancing incidence, was observed and registered photographically. Silver precipitates could be detected by their diffraction pattern, when the crystallites had grown to a size of about 50 A. From all materials investigated silveriodide showed maximum sensitivity. The precipitates formed show no orientation with respect to the host crystal. From the temperature dependence of the sensitivity an activation energy of 0.12 eV can be deduced leading to interstitial ion migration as rate determining step. Pure silverchloride can not been radiolyzed by 40 kV-electrons. After doping it with 0.3 mol% CaCl 2 or MgCl 2 it becomes very sensitive. The precipitate showes orientation with respect to the host lattice. Also pure CuJ is resistant against the electron beam. Mixed crystals (Ag, Cu)J with xsub(AgJ) > 0.5 behave similar as pure AgJ. Pb(II)-halides show no sensitivity, but the compounds AgBr x 2 PbBr 2 and 5 AgJ x PbJ 2 are readily radiolyzed, forming polycrystalline silver precipitates. The mechanism of radiolysis, its dependency on temperature and film thickness is discussed. (orig.) [de

  20. Multifunctional-layered materials for creating membrane-restricted nanodomains and nanoscale imaging

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, P., E-mail: prasri@ece.ucsb.edu, E-mail: srinivasan@lifesci.ucsb.edu [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, USA and Neuroscience Research Institute, University of California, Santa Barbara, California 93106 (United States)

    2016-01-18

    Experimental platform that allows precise spatial positioning of biomolecules with an exquisite control at nanometer length scales is a valuable tool to study the molecular mechanisms of membrane bound signaling. Using micromachined thin film gold (Au) in layered architecture, it is possible to add both optical and biochemical functionalities in in vitro. Towards this goal, here, I show that docking of complementary DNA tethered giant phospholiposomes on Au surface can create membrane-restricted nanodomains. These nanodomains are critical features to dissect molecular choreography of membrane signaling complexes. The excited surface plasmon resonance modes of Au allow label-free imaging at diffraction-limited resolution of stably docked DNA tethered phospholiposomes, and lipid-detergent bicelle structures. Such multifunctional building block enables realizing rigorously controlled in vitro set-up to model membrane anchored biological signaling, besides serving as an optical tool for nanoscale imaging.