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Sample records for nanowires nanoparticle films

  1. Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon microcolumn arrays

    International Nuclear Information System (INIS)

    Chen Yong; Luo Guanghong; Diao Jiajie; Chornoguz, Olesya; Reeves, Mark; Vertes, Akos

    2007-01-01

    Due to their optical properties and morphology, thin films formed of nanoparticles are potentially new platforms for soft laser desorption/ionization (SLDI) mass spectrometry. Thin films of gold nanoparticles (with 12±1 nm particle size) were prepared by evaporation-driven vertical colloidal deposition and used to analyze a series of directly deposited polypeptide samples. In this new SLDI method, the required laser fluence for ion detection was equal or less than what was needed for matrix-assisted laser desorption/ionization (MALDI) but the resulting spectra were free of matrix interferences. A silicon microcolumn array-based substrate (a.k.a. black silicon) was developed as a new matrix-free laser desorption ionization surface. When low-resistivity silicon wafers were processed with a 22 ps pulse length 3xω Nd:YAG laser in air, SF 6 or water environment, regularly arranged conical spikes emerged. The radii of the spike tips varied with the processing environment, ranging from approximately 500 nm in water, to ∼2 μm in SF 6 gas and to ∼5 μm in air. Peptide mass spectra directly induced by a nitrogen laser showed the formation of protonated ions of angiotensin I and II, substance P, bradykinin fragment 1-7, synthetic peptide, pro14-arg, and insulin from the processed silicon surfaces but not from the unprocessed areas. Threshold fluences for desorption/ionization were similar to those used in MALDI. Although compared to silicon nanowires the threshold laser pulse energy for ionization is significantly (∼10x) higher, the ease of production and robustness of microcolumn arrays offer complementary benefits

  2. Detection of chemical substances in water using an oxide nanowire transistor covered with a hydrophobic nanoparticle thin film as a liquid-vapour separation filter

    Directory of Open Access Journals (Sweden)

    Taekyung Lim

    2016-08-01

    Full Text Available We have developed a method to detect the presence of small amounts of chemical substances in water, using a Al2O3 nanoparticle thin film covered with phosphonic acid (HDF-PA self-assembled monolayer. The HDF-PA self-assembled Al2O3 nanoparticle thin film acts as a liquid-vapour separation filter, allowing the passage of chemical vapour while blocking liquids. Prevention of the liquid from contacting the SnO2 nanowire and source-drain electrodes is required in order to avoid abnormal operation. Using this characteristic, the concentration of chemical substances in water could be evaluated by measuring the current changes in the SnO2 nanowire transistor covered with the HDF-PA self-assembled Al2O3 nanoparticle thin film.

  3. Electrical and optical characteristics of heterojunction devices composed of silicon nanowires and mercury selenide nanoparticle films on flexible plastics.

    Science.gov (United States)

    Yeo, Minje; Yun, Junggwon; Kim, Sangsig

    2013-09-01

    A pn heterojunction device based on p-type silicon (Si) nanowires (NWs) prepared by top-down method and n-type mercury selenide (HgSe) nanoparticles (NPs) synthesized by the colloidal method have been fabricated on a flexible plastic substrate. The synthesized HgSe NPs were analyzed through the effective mass approximation. The characteristics of the heterojunction device were examined and studied with the energy band diagram. The device showed typical diode characteristics with a turn-on voltage of 1.5 V and exhibited a high rectification ratio of 10(3) under relatively low forward bias. Under illumination of 633-nm-wavelength light, the device presented photocurrent efficiency of 117.5 and 20.1 nA/W under forward bias and reverse bias conditions, respectively. Moreover, the photocurrent characteristics of the device have been determined by bending of the plastic substrate upward and downward with strain of 0.8%. Even though the photocurrent efficiency has fluctuations during the bending cycles, the values are roughly maintained for 10(4) bending cycles. This result indicates that the fabricated heterojunction device has the potential to be applied as fundamental elements of flexible nanoelectronics.

  4. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications

    International Nuclear Information System (INIS)

    Dong Wenjun; Huang Huandi; Zhu Yanjun; Li Xiaoyun; Wang Xuebin; Li Chaorong; Chen Benyong; Wang Ge; Shi Zhan

    2012-01-01

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide–amine intermediate and Ag + at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO 3 nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag–MoO 3 nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature. (paper)

  5. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications.

    Science.gov (United States)

    Dong, Wenjun; Huang, Huandi; Zhu, Yanjun; Li, Xiaoyun; Wang, Xuebin; Li, Chaorong; Chen, Benyong; Wang, Ge; Shi, Zhan

    2012-10-26

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide-amine intermediate and Ag(+) at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO(3) nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag-MoO(3) nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature.

  6. A universal approach to electrically connecting nanowire arrays using nanoparticles-application to a novel gas sensor architecture

    International Nuclear Information System (INIS)

    Parthangal, Prahalad M; Cavicchi, Richard E; Zachariah, Michael R

    2006-01-01

    We report on a novel, in situ approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles. The utility of the approach is demonstrated by development of a gas sensing device employing this nano-architecture. Well-aligned, single-crystalline zinc oxide nanowires were grown through a direct thermal evaporation process at 550 deg. C on gold catalyst layers. Electrical contact to the top of the nanowire array was established by creating a contiguous nanoparticle film through electrostatic attachment of conductive gold nanoparticles exclusively onto the tips of nanowires. A gas sensing device was constructed using such an arrangement and the nanowire assembly was found to be sensitive to both reducing (methanol) and oxidizing (nitrous oxides) gases. This assembly approach is amenable to any nanowire array for which a top contact electrode is needed

  7. Fabrication of isolated platinum nanowire gratings and nanoparticles on silica substrate by femtosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Yasutaka [School of Integrated Design Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223- 8522 (Japan); Nedyalkov, Nikolay [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko shouse 72, Sofia 1784 (Bulgaria); Department of Electronics and Electrical Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522 (Japan); Takami, Akihiro [School of Integrated Design Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223- 8522 (Japan); Terakawa, Mitsuhiro, E-mail: terakawa@elec.keio.ac.jp [School of Integrated Design Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223- 8522 (Japan); Department of Electronics and Electrical Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522 (Japan)

    2017-02-01

    Highlights: • Formation of HSFL with periodicities shorter than 100 nm. • Structural evolution from platinum nanowire gratings to platinum nanoparticles only by increasing the number of pulses. • Melting and fragmentation of the nanowire gratings would play a key role in structural evolution. - Abstract: We demonstrate the fabrication of isolated platinum nanostructures on a silica substrate by using femtosecond laser. Nanowire gratings which have short periodicities of approximately 50 nm were formed by irradiating a platinum thin film deposited on a fused silica substrate with 800-nm wavelength femtosecond laser pulses. The structural evolution from the nanowire gratings to nanoparticles was observed only by increasing the number of pulses. The periodicities or diameters of the structures showed good uniformity. Scanning electron microscopy of the surfaces and theoretical calculation of temperature profile using a two-temperature model revealed that the structural evolution can be attributed to the fragmentation of the formed nanowires. The presented method provides a simple and high-throughput technique for fabricating both metal nanowire gratings and nanoparticles, which have the potential to be used for the fabrication of optical, electrical and biomedical devices.

  8. Electrochemical Deposition of Lanthanum Telluride Thin Films and Nanowires

    Science.gov (United States)

    Chi, Su (Ike); Farias, Stephen; Cammarata, Robert

    2013-03-01

    Tellurium alloys are characterized by their high performance thermoelectric properties and recent research has shown nanostructured tellurium alloys display even greater performance than bulk equivalents. Increased thermoelectric efficiency of nanostructured materials have led to significant interests in developing thin film and nanowire structures. Here, we report on the first successful electrodeposition of lanthanum telluride thin films and nanowires. The electrodeposition of lanthanum telluride thin films is performed in ionic liquids at room temperature. The synthesis of nanowires involves electrodepositing lanthanum telluride arrays into anodic aluminum oxide (AAO) nanoporous membranes. These novel procedures can serve as an alternative means of simple, inexpensive and laboratory-environment friendly methods to synthesize nanostructured thermoelectric materials. The thermoelectric properties of thin films and nanowires will be presented to compare to current state-of-the-art thermoelectric materials. The morphologies and chemical compositions of the deposited films and nanowires are characterized using SEM and EDAX analysis.

  9. Dynamical formation of spatially localized arrays of aligned nanowires in plastic films with magnetic anisotropy.

    Science.gov (United States)

    Fragouli, Despina; Buonsanti, Raffaella; Bertoni, Giovanni; Sangregorio, Claudio; Innocenti, Claudia; Falqui, Andrea; Gatteschi, Dante; Cozzoli, Pantaleo Davide; Athanassiou, Athanassia; Cingolani, Roberto

    2010-04-27

    We present a simple technique for magnetic-field-induced formation, assembling, and positioning of magnetic nanowires in a polymer film. Starting from a polymer/iron oxide nanoparticle casted solution that is allowed to dry along with the application of a weak magnetic field, nanocomposite films incorporating aligned nanocrystal-built nanowire arrays are obtained. The control of the dimensions of the nanowires and of their localization across the polymer matrix is achieved by varying the duration of the applied magnetic field, in combination with the evaporation dynamics. These multifunctional anisotropic free-standing nanocomposite films, which demonstrate high magnetic anisotropy, can be used in a wide field of technological applications, ranging from sensors to microfluidics and magnetic devices.

  10. Manganese oxide nanowires, films, and membranes and methods of making

    Science.gov (United States)

    Suib, Steven Lawrence [Storrs, CT; Yuan, Jikang [Storrs, CT

    2008-10-21

    Nanowires, films, and membranes comprising ordered porous manganese oxide-based octahedral molecular sieves, and methods of making, are disclosed. A single crystal ultra-long nanowire includes an ordered porous manganese oxide-based octahedral molecular sieve, and has an average length greater than about 10 micrometers and an average diameter of about 5 nanometers to about 100 nanometers. A film comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is stacked on a surface of a substrate, wherein the nanowires of each layer are substantially axially aligned. A free standing membrane comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is aggregately stacked, and wherein the nanowires of each layer are substantially axially aligned.

  11. Tungsten oxide nanowires grown on amorphous-like tungsten films

    International Nuclear Information System (INIS)

    Dellasega, D; Pezzoli, A; Russo, V; Passoni, M; Pietralunga, S M; Nasi, L; Conti, C; Vahid, M J; Tagliaferri, A

    2015-01-01

    Tungsten oxide nanowires have been synthesized by vacuum annealing in the range 500–710 °C from amorphous-like tungsten films, deposited on a Si(100) substrate by pulsed laser deposition (PLD) in the presence of a He background pressure. The oxygen required for the nanowires formation is already adsorbed in the W matrix before annealing, its amount depending on deposition parameters. Nanowire crystalline phase and stoichiometry depend on annealing temperature, ranging from W_1_8O_4_9-Magneli phase to monoclinic WO_3. Sufficiently long annealing induces the formation of micrometer-long nanowires, up to 3.6 μm with an aspect ratio up to 90. Oxide nanowire growth appears to be triggered by the crystallization of the underlying amorphous W film, promoting their synthesis at low temperatures. (paper)

  12. Optical haze of randomly arranged silver nanowire transparent conductive films with wide range of nanowire diameters

    Directory of Open Access Journals (Sweden)

    M. Marus

    2018-03-01

    Full Text Available The effect of the diameter of randomly arranged silver nanowires on the optical haze of silver nanowire transparent conductive films was studied. Proposed simulation model behaved similarly with the experimental results, and was used to theoretically study the optical haze of silver nanowires with diameters in the broad range from 30 nm and above. Our results show that a thickening of silver nanowires from 30 to 100 nm results in the increase of the optical haze up to 8 times, while from 100 to 500 nm the optical haze increases only up to 1.38. Moreover, silver nanowires with diameter of 500 nm possess up to 5% lower optical haze and 5% higher transmittance than 100 nm thick silver nanowires for the same 10-100 Ohm/sq sheet resistance range. Further thickening of AgNWs can match the low haze of 30 nm thick AgNWs, but at higher transmittance. The results obtained from this work allow deeper analysis of the silver nanowire transparent conductive films from the perspective of the diameter of nanowires for various optoelectronic devices.

  13. Time-dependent optical response of three-dimensional Au nanoparticle arrays formed on silica nanowires

    Science.gov (United States)

    Di Mario, Lorenzo; Otomalo, Tadele Orbula; Catone, Daniele; O'Keeffe, Patrick; Tian, Lin; Turchini, Stefano; Palpant, Bruno; Martelli, Faustino

    2018-03-01

    We present stationary and transient absorption measurements on 3D Au nanoparticle (NP)-decorated Si O2 nanowire arrays. The 3D NP array has been produced by the dewetting of a thin Au film deposited on silica nanowires produced by oxidation of silicon nanowires. The experimental behaviors of the spectral and temporal dynamics observed in the experiment are accurately described by a two-step, three-temperature model. Using an arbitrary set of Au NPs with different aspect ratios, we demonstrate that the width of the experimental spectra, the energy shift of their position with time, and the asymmetry between the two positive wings in the dynamical variation of absorption can all be attributed to the nonuniform shape distribution of the Au NPs in the sample.

  14. 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

  15. Hole-dominated transport in InSb nanowires grown on high-quality InSb films

    Energy Technology Data Exchange (ETDEWEB)

    Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U., E-mail: usha.philipose@unt.edu [University of North Texas, Department of Physics (United States)

    2016-12-15

    We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between Sb{sub 2}S{sub 3} and In and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40–60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 10{sup 17} cm{sup −3} and 1000 cm{sup 2} V{sup −1} s{sup −1}, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

  16. Hole-dominated transport in InSb nanowires grown on high-quality InSb films

    Science.gov (United States)

    Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U.

    2016-12-01

    We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between S b 2 S 3 and I n and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40-60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 1017 cm-3 and 1000 cm2 V-1 s-1, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

  17. Controlled formation of metallic nanowires via Au nanoparticle ac trapping

    International Nuclear Information System (INIS)

    Bernard, L; Calame, M; Molen, S J van der; Liao, J; Schoenenberger, C

    2007-01-01

    Applying ac voltages, we trapped gold nanoparticles between micro-fabricated electrodes under well-defined conditions. We demonstrate that the nanoparticles can be controllably fused together to form homogeneous gold nanowires with pre-defined diameters and conductance values. Whereas electromigration is known to form a gap when a dc voltage is applied, this ac technique achieves the opposite, thereby completing the toolkit for the fabrication of nanoscale junctions

  18. Controlled formation of metallic nanowires via Au nanoparticle ac trapping

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, L; Calame, M; Molen, S J van der; Liao, J; Schoenenberger, C [Institute of Physics, University of Basel, CH-4056 Basel (Switzerland)

    2007-06-13

    Applying ac voltages, we trapped gold nanoparticles between micro-fabricated electrodes under well-defined conditions. We demonstrate that the nanoparticles can be controllably fused together to form homogeneous gold nanowires with pre-defined diameters and conductance values. Whereas electromigration is known to form a gap when a dc voltage is applied, this ac technique achieves the opposite, thereby completing the toolkit for the fabrication of nanoscale junctions.

  19. 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

  20. Nanocatalytic growth of Si nanowires from Ni silicate coated SiC nanoparticles on Si solar cell.

    Science.gov (United States)

    Parida, Bhaskar; Choi, Jaeho; Ji, Hyung Yong; Park, Seungil; Lim, Gyoungho; Kim, Keunjoo

    2013-09-01

    We investigated the nanocatalytic growth of Si nanowires on the microtextured surface of crystalline Si solar cell. 3C-SiC nanoparticles have been used as the base for formation of Ni silicate layer in a catalytic reaction with the Si melt under H2 atmosphere at an annealing temperature of 1100 degrees C. The 10-nm thick Ni film was deposited after the SiC nanoparticles were coated on the microtextured surface of the Si solar cell by electron-beam evaporation. SiC nanoparticles form a eutectic alloy surface of Ni silicate and provide the base for Si supersaturation as well as the Ni-Si alloy layer on Si substrate surface. This bottom reaction mode for the solid-liquid-solid growth mechanism using a SiC nanoparticle base provides more stable growth of nanowires than the top reaction mode growth mechanism in the absence of SiC nanoparticles. Thermally excited Ni nanoparticle forms the eutectic alloy and provides collectively excited electrons at the alloy surface, which reduces the activation energy of the nanocatalytic reaction for formation of nanowires.

  1. Magnetic properties of nickel nanowires decorated with cobalt nanoparticles fabricated by two step electrochemical deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Maaz, K., E-mail: maaz@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, 45650, Islamabad (Pakistan); Duan, J.L. [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Karim, S. [Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, 45650, Islamabad (Pakistan); Chen, Y.H.; Yao, H.J.; Mo, D.; Sun, Y.M. [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Liu, J., E-mail: j.liu@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2016-10-01

    We demonstrate fabrication and magnetic characterization of novel nanostructures composed of Ni nanowires decorated with Co nanoparticles by two step etching and electrochemical deposition in polycarbonate template. Structural analysis confirmed the formation of nickel nanowires with diameter of 62 nm which are surrounded by cobalt nanoparticles of about 15 nm in diameter. By electron microscopy analyses it is evident that the nanoparticles are distributed on the surface of the nanowires. Analysis of magnetization data indicates that ferromagnetic Ni nanowires exhibit an easy axis of magnetization parallel to the wire long-axis while the angular dependence of coercivity indicates that magnetization reversal occurs through the curling process in these nanowires. An exchange bias accompanied by vertical shift in magnetization was observed below ∼20 K, measured under a cooling field of 1 kOe, which is attributed to the spin interactions between the spin-glass like surface layer and ferromagnetic core of the nanowires and nanoparticles. - Highlights: • Co-decorated Ni nanowires were fabricated by two-step electrodeposition technique. • The nanoparticles are distributed on the surface of nanowires. • Magnetization reversal occurs through the curling process in the nanowires. • Temperature dependent coercivity follows thermal activation model.

  2. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    International Nuclear Information System (INIS)

    Ye Zuxin; Lyuksyutov, Igor F; Wu Wenhao; Naugle, Donald G

    2011-01-01

    The superconducting properties of Pb 82 Bi 18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb 82 Bi 18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb 82 Bi 18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  3. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    Science.gov (United States)

    Ye, Zuxin; Lyuksyutov, Igor F.; Wu, Wenhao; Naugle, Donald G.

    2011-02-01

    The superconducting properties of Pb82Bi18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb82Bi18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb82Bi18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  4. Superconducting Properties of Lead-Bismuth Films Controlled by Ferromagnetic Nanowire Arrays

    Science.gov (United States)

    Ye, Zuxin; Lyuksyutov, Igor F.; Wu, Wenhao; Naugle, Donald G.

    2011-03-01

    Superconducting properties of lead-bismuth (82% Pb and 18% Bi) alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb 82 Bi 18 films are then quench-condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb 82 Bi 18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and the material variety was observed.

  5. Si nanoparticle-decorated Si nanowire networks for Li-ion battery anodes

    KAUST Repository

    Hu, Liangbing

    2011-01-01

    We designed and fabricated binder-free, 3D porous silicon nanostructures for Li-ion battery anodes, where Si nanoparticles electrically contact current collectors via vertically grown silicon nanowires. When compared with a Si nanowire anode, the areal capacity was increased by a factor of 4 without having to use long, high temperature steps under vacuum that vapour-liquid-solid Si nanowire growth entails. © 2011 The Royal Society of Chemistry.

  6. Nanowire growth from the viewpoint of the thin film polylayer growth theory

    Science.gov (United States)

    Kashchiev, Dimo

    2018-03-01

    The theory of polylayer growth of thin solid films is employed for description of the growth kinetics of single-crystal nanowires. Expressions are derived for the dependences of the height h and radius r of a given nanowire on time t, as well as for the h(r) dependence. These dependences are applicable immediately after the nanowire nucleation on the substrate and thus include the period during which the nucleated nanowire changes its shape from that of cap to that of column. The analysis shows that the nanowire cap-to-column shape transition is continuous and makes it possible to kinetically define the nanowire shape-transition radius by means of the nanowire radial and axial growth rates. The obtained h(t), r(t) and h(r) dependences are found to provide a good description of available experimental data for growth of self-nucleated GaN nanowires by the vapor-solid mechanism.

  7. Nanoparticle Stability in Axial InAs-InP Nanowire Heterostructures with Atomically Sharp Interfaces.

    Science.gov (United States)

    Zannier, Valentina; Rossi, Francesca; Dubrovskii, Vladimir G; Ercolani, Daniele; Battiato, Sergio; Sorba, Lucia

    2018-01-10

    The possibility to expand the range of material combinations in defect-free heterostructures is one of the main motivations for the great interest in semiconductor nanowires. However, most axial nanowire heterostructures suffer from interface compositional gradients and kink formation, as a consequence of nanoparticle-nanowire interactions during the metal-assisted growth. Understanding such interactions and how they affect the growth mode is fundamental to achieve a full control over the morphology and the properties of nanowire heterostructures for device applications. Here we demonstrate that the sole parameter affecting the growth mode (straight or kinked) of InP segments on InAs nanowire stems by the Au-assisted method is the nanoparticle composition. Indeed, straight InAs-InP nanowire heterostructures are obtained only when the In/Au ratio in the nanoparticles is low, typically smaller than 1.5. For higher In content, the InP segments tend to kink. Tailoring the In/Au ratio by the precursor fluxes at a fixed growth temperature enables us to obtain straight and radius-uniform InAs-InP nanowire heterostructures (single and double) with atomically sharp interfaces. We present a model that is capable of describing all the experimentally observed phenomena: straight growth versus kinking, the stationary nanoparticle compositions in pure InAs and InAs-InP nanowires, the crystal phase trends, and the interfacial abruptness. By taking into account different nanowire/nanoparticle interfacial configurations (forming wetting or nonwetting monolayers in vertical or tapered geometry), our generalized model provides the conditions of nanoparticle stability and abrupt heterointerfaces for a rich variety of growth scenarios. Therefore, our results provide a powerful tool for obtaining high quality InAs-InP nanowire heterostructures with well-controlled properties and can be extended to other material combinations based on the group V interchange.

  8. Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

    KAUST Repository

    Fatieiev, Yevhen; Croissant, Jonas G.; Alamoudi, Kholod; Khashab, Niveen M.

    2017-01-01

    This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role

  9. Atomistic simulations of the structures of Pd-Pt bimetallic nanoparticles and nanowires

    OpenAIRE

    Yun, Kayoung; Cha, Pil-Ryung; Lee, Jaegab; Kim, Jiyoung; Nam, Ho-Seok

    2015-01-01

    Bimetallic nanoalloys such as nanoparticles and nanowires are attracting significant attention due to their vast potential applications such as in catalysis and nanoelectronics. Notably, Pd-Pt nanoparticles/nanowires are being widely recognized as catalysts and hydrogen sensors. Compared to unary systems, alloys present more structural complexity with various compositional configurations. Therefore, it is important to understand energetically preferred atomic structures of bimetallic nanoallo...

  10. Au nanoparticles decorated SiO{sub 2} nanowires by dewetting on curved surfaces: facile synthesis and nanoparticles-nanowires sizes correlation

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Grimaldi, M. G. [Universita di Catania, Dipartimento di Fisica e Astronomia (Italy)

    2013-09-15

    We report a solid-state synthesis for SiO{sub 2} nanowires (NWs) (up to 20 microns in length and from about 40 to about 150 nm in diameter) coated by Au nanoparticles (NPs) (from about 20 to about 80 nm in diameter). This protocol is based on three steps: (1) large area production of very long SiO{sub 2} NWs on a Si surface exploiting a simple Au/Si solid-state reaction at high temperature; (2) coating of the SiO{sub 2} NWs by a Au film of desired thickness using sputtering depositions; and (3) a thermal process to induce a dewetting process of the Au-film coating the SiO{sub 2} NWs to obtain Au NPs on the curved surface of the NWs. The morphology evolution of the SiO{sub 2} NWs was followed, in each step, by scanning electron microscopy analyses. They allowed to correlate the evolution of the NPs size with the NWs sizes for different thicknesses of the starting Au-film coating the NWs and different annealing temperatures of the dewetting process. Some theoretical concepts, related to the dewetting process of a film on a curved surface were used to describe the experimental data. The main advantages of the proposed protocols include: (i) simplicity and low-cost (it is based only on sputtering depositions and thermal processes), and (ii) versatility based on the possibility of tuning Au-film thickness and annealing temperature to tune the NPs-NWs sizes ratio. These advantages can make this technique suitable for the mass production of Au NPs-coated SiO{sub 2} NWs toward applications in electronic devices, biosensors, and nanoscale optical devices.

  11. Surface vertical deposition for gold nanoparticle film

    International Nuclear Information System (INIS)

    Diao, J J; Qiu, F S; Chen, G D; Reeves, M E

    2003-01-01

    In this rapid communication, we present the surface vertical deposition (SVD) method to synthesize the gold nanoparticle films. Under conditions where the surface of the gold nanoparticle suspension descends slowly by evaporation, the gold nanoparticles in the solid-liquid-gas junction of the suspension aggregate together on the substrate by the force of solid and liquid interface. When the surface properties of the substrate and colloidal nanoparticle suspension define for the SVD, the density of gold nanoparticles in the thin film made by SVD only depends on the descending velocity of the suspension surface and on the concentration of the gold nanoparticle suspension. (rapid communication)

  12. Polyaniline nanowires-gold nanoparticles hybrid network based chemiresistive hydrogen sulfide sensor

    Science.gov (United States)

    Shirsat, Mahendra D.; Bangar, Mangesh A.; Deshusses, Marc A.; Myung, Nosang V.; Mulchandani, Ashok

    2009-02-01

    We report a sensitive, selective, and fast responding room temperature chemiresistive sensor for hydrogen sulfide detection and quantification using polyaniline nanowires-gold nanoparticles hybrid network. The sensor was fabricated by facile electrochemical technique. Initially, polyaniline nanowires with a diameter of 250-320 nm bridging the gap between a pair of microfabricated gold electrodes were synthesized using templateless electrochemical polymerization using a two step galvanostatic technique. Polyaniline nanowires were then electrochemically functionalized with gold nanoparticles using cyclic voltammetry technique. These chemiresistive sensors show an excellent limit of detection (0.1 ppb), wide dynamic range (0.1-100 ppb), and very good selectivity and reproducibility.

  13. Silicon nanowires in polymer nanocomposites for photovoltaic hybrid thin films

    International Nuclear Information System (INIS)

    Ben Dkhil, S.; Bourguiga, R.; Davenas, J.; Cornu, D.

    2012-01-01

    Highlights: ► Hybrid solar cells based on blends of poly(N-vinylcarbazole) and silicon nanowires have been fabricated. ► We have investigated the charge transfer between PVK and SiNWs by the way of the quenching of the PVK photoluminescence. ► The relation between the morphology of the composite thin films and the charge transfer between SiNWs and PVK has been examined. ► We have investigated the effects of SiNWs concentration on the photovoltaic characteristics leading to the optimization of a critical SiNWs concentration. - Abstract: Hybrid thin films combining the high optical absorption of a semiconducting polymer film and the electronic properties of silicon fillers have been investigated in the perspective of the development of low cost solar cells. Bulk heterojunction photovoltaic materials based on blends of a semiconductor polymer poly(N-vinylcarbazole) (PVK) as electron donor and silicon nanowires (SiNWs) as electron acceptor have been studied. Composite PVK/SiNWs films were cast from a common solvent mixture. UV–visible spectrometry and photoluminescence of the composites have been studied as a function of the SiNWs concentration. Photoluminescence spectroscopy (PL) shows the existence of a critical SiNWs concentration of about 10 wt % for PL quenching corresponding to the most efficient charge pair separation. The photovoltaic (PV) effect has been studied under illumination. The optimum open-circuit voltage V oc and short-circuit current density J sc are obtained for 10 wt % SiNWs whereas a degradation of these parameters is observed at higher SiNWs concentrations. These results are correlated to the formation of aggregates in the composite leading to recombination of the photogenerated charge pairs competing with the dissociation mechanism.

  14. Superconductivity of a Sn film controlled by an array of Co nanowires

    Science.gov (United States)

    Wei, Z.; Ye, Z.; Rathnayaka, K. D. D.; Lyuksyutov, I. F.; Wu, W.; Naugle, D. G.

    2012-09-01

    Superconducting properties of a hybrid structure composed of ferromagnetic Co nanowire arrays and a superconducting Sn film have been investigated. Ordered Co nanowires arrays with 60 nm, 150 nm and 200 nm diameter were electroplated into the pores of self organized Anodic Aluminum Oxide (AAO) membranes. Hysteretic dependence of the Sn film superconducting properties on applied magnetic field and critical current enhancement at moderate fields has been observed. This behavior strongly depends on the ratio of the Sn film thickness to the Co nanowire diameter.

  15. Superconductivity of a Sn film controlled by an array of Co nanowires

    International Nuclear Information System (INIS)

    Wei, Z.; Ye, Z.; Rathnayaka, K.D.D.; Lyuksyutov, I.F.; Wu, W.; Naugle, D.G.

    2012-01-01

    Superconducting properties of a hybrid structure composed of ferromagnetic Co nanowire arrays and a superconducting Sn film have been investigated. Ordered Co nanowires arrays with 60 nm, 150 nm and 200 nm diameter were electroplated into the pores of self organized Anodic Aluminum Oxide (AAO) membranes. Hysteretic dependence of the Sn film superconducting properties on applied magnetic field and critical current enhancement at moderate fields has been observed. This behavior strongly depends on the ratio of the Sn film thickness to the Co nanowire diameter.

  16. Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique.

    Science.gov (United States)

    Lopez-Diaz, D; Merino, C; Velázquez, M M

    2015-11-11

    Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP) and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

  17. Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique

    Directory of Open Access Journals (Sweden)

    D. Lopez-Diaz

    2015-11-01

    Full Text Available Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

  18. Mass production of polymer nano-wires filled with metal nano-particles.

    Science.gov (United States)

    Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

    2017-08-17

    Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

  19. Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

    KAUST Repository

    Phadke, Sujay; Lee, Jung-Yong; West, Jack; Peumans, Peter; Salleo, Alberto

    2011-01-01

    of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires. Solution processed Gallium doped ZnO nanowires are aligned on substrates using

  20. Dislocation-induced nanoparticle decoration on a GaN nanowire.

    Science.gov (United States)

    Yang, Bing; Yuan, Fang; Liu, Qingyun; Huang, Nan; Qiu, Jianhang; Staedler, Thorsten; Liu, Baodan; Jiang, Xin

    2015-02-04

    GaN nanowires with homoepitaxial decorated GaN nanoparticles on their surface along the radial direction have been synthesized by means of a chemical vapor deposition method. The growth of GaN nanowires is catalyzed by Au particles via the vapor-liquid-solid (VLS) mechanism. Screw dislocations are generated along the radial direction of the nanowires under slight Zn doping. In contrast to the metal-catalyst-assisted VLS growth, GaN nanoparticles are found to prefer to nucleate and grow at these dislocation sites. High-resolution transmission electron microscopy (HRTEM) analysis demonstrates that the GaN nanoparticles possess two types of epitaxial orientation with respect to the corresponding GaN nanowire: (I) [1̅21̅0]np//[1̅21̅0]nw, (0001)np//(0001)nw; (II) [1̅21̅3]np//[12̅10]nw, (101̅0)np//(101̅0)nw. An increased Ga signal in the energy-dispersive spectroscopy (EDS) profile lines of the nanowires suggests GaN nanoparticle growth at the edge surface of the wires. All the crystallographic results confirm the importance of the dislocations with respect to the homoepitaxial growth of the GaN nanoparticles. Here, screw dislocations situated on the (0001) plane provide the self-step source to enable nucleation of the GaN nanoparticles.

  1. Nanoparticle-mediated nonclassical crystal growth of sodium fluorosilicate nanowires and nanoplates

    Directory of Open Access Journals (Sweden)

    Hongxia Li

    2011-12-01

    Full Text Available We observed nonclassical crystal growth of the sodium fluorosilicate nanowires, nanoplates, and hierarchical structures through self-assembly and aggregation of primary intermediate nanoparticles. Unlike traditional ion-by-ion crystallization, the primary nanoparticles formed first and their subsequent self-assembly, fusion, and crystallization generated various final crystals. These findings offer direct evidences for the aggregation-based crystallization mechanism.

  2. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    International Nuclear Information System (INIS)

    Zhou Weiping; Li Meng; Koenigsmann, Christopher; Ma Chao; Wong, Stanislaus S.; Adzic, Radoslav R.

    2011-01-01

    Highlights: → We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. → Pt nanowires and nanoparticles were used as catalysts. → Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. → The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO 2 -to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  3. Different growth regimes in InP nanowire growth mediated by Ag nanoparticles.

    Science.gov (United States)

    Oliveira, D S; Zavarize, M; Tizei, L H G; Walls, M; Ospina, C A; Iikawa, F; Ugarte, D; Cotta, M A

    2017-12-15

    We report on the existence of two different regimes in one-step Ag-seeded InP nanowire growth. The vapor-liquid-solid-mechanism is present at larger In precursor flows and temperatures, ∼500 °C, yielding high aspect ratio and pure wurtzite InP nanowires with a semi-spherical metal particle at the thin apex. Periodic diameter oscillations can be achieved under extreme In supersaturations at this temperature range, showing the presence of a liquid catalyst. However, under lower temperatures and In precursor flows, large diameter InP nanowires with mixed wurtzite/zincblende segments are obtained, similarly to In-assisted growth. Chemical composition analysis suggest that In-rich droplet formation is catalyzed at the substrate surface via Ag nanoparticles; this process might be facilitated by the sulfur contamination detected in these nanoparticles. Furthermore, part of the original Ag nanoparticle remains solid and is embedded inside the actual catalyst, providing an in situ method to switch growth mechanisms upon changing In precursor flow. Nevertheless, our Ag-seeded InP nanowires exhibit overall optical emission spectra consistent with the observed structural properties and similar to Au-catalyzed InP nanowires. We thus show that Ag nanoparticles may be a suitable replacement for Au in InP nanowire growth.

  4. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Weiping, E-mail: wpzhou@bnl.gov [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Li Meng [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Koenigsmann, Christopher [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Ma Chao [Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Wong, Stanislaus S. [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Adzic, Radoslav R. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-11-30

    Highlights: > We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. > Pt nanowires and nanoparticles were used as catalysts. > Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. > The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO{sub 2}-to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  5. 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.

  6. Silver Nanowire Transparent Conductive Films with High Uniformity Fabricated via a Dynamic Heating Method.

    Science.gov (United States)

    Jia, Yonggao; Chen, Chao; Jia, Dan; Li, Shuxin; Ji, Shulin; Ye, Changhui

    2016-04-20

    The uniformity of the sheet resistance of transparent conductive films is one of the most important quality factors for touch panel applications. However, the uniformity of silver nanowire transparent conductive films is far inferior to that of indium-doped tin oxide (ITO). Herein, we report a dynamic heating method using infrared light to achieve silver nanowire transparent conductive films with high uniformity. This method can overcome the coffee ring effect during the drying process and suppress the aggregation of silver nanowires in the film. A nonuniformity factor of the sheet resistance of the as-prepared silver nanowire transparent conductive films could be as low as 6.7% at an average sheet resistance of 35 Ω/sq and a light transmittance of 95% (at 550 nm), comparable to that of high-quality ITO film in the market. In addition, a mechanical study shows that the sheet resistance of the films has little change after 5000 bending cycles, and the film could be used in touch panels for human-machine interactive input. The highly uniform and mechanically stable silver nanowire transparent conductive films meet the requirement for many significant applications and could play a key role in the display market in a near future.

  7. Applications of Silver Nanowires on Transparent Conducting Film and Electrode of Electrochemical Capacitor

    Directory of Open Access Journals (Sweden)

    Yuan-Jun Song

    2014-01-01

    Full Text Available Silver nanowire has potential applications on transparent conducting film and electrode of electrochemical capacitor due to its excellent conductivity. Transparent conducting film (G-film was prepared by coating silver nanowires on glass substrate using Meyer rod method, which exhibited better performance than carbon nanotube and graphene. The conductivity of G-film can be improved by increasing sintering temperature. Electrode of electrochemical capacitor (I-film was fabricated through the same method with G-film on indium tin oxide (ITO. CV curves of I-film under different scanning rates had obvious redox peaks, which indicated that I-film exhibited excellent electrochemical pseudocapacitance performance and good reversibility during charge/discharge process. In addition, the specific capacitance of I-film was measured by galvanostatic charge/discharge experiments, indicating that I-film exhibits high special capacitance and excellent electrochemical stability.

  8. Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

    International Nuclear Information System (INIS)

    Subramania, A; Kumar, G Vijaya; Priya, A R Sathiya; Vasudevan, T

    2007-01-01

    The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively

  9. Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Subramania, A; Kumar, G Vijaya; Priya, A R Sathiya; Vasudevan, T [Advanced Materials Research Lab, Department of Industrial Chemistry, Alagappa University, Karaikudi-630 003 (India)

    2007-06-06

    The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively.

  10. Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

    Science.gov (United States)

    Subramania, A.; Vijaya Kumar, G.; Sathiya Priya, A. R.; Vasudevan, T.

    2007-06-01

    The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively.

  11. Redox exchange induced MnO2 nanoparticle enrichment in poly(3,4-ethylenedioxythiophene) nanowires for electrochemical energy storage.

    Science.gov (United States)

    Liu, Ran; Duay, Jonathon; Lee, Sang Bok

    2010-07-27

    MnO2 nanoparticle enriched poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires are fabricated by simply soaking the PEDOT nanowires in potassium permanganate (KMnO4) solution. The structures of these MnO2 nanoparticle enriched PEDOT nanowires are characterized by SEM and TEM, which show that the MnO2 nanoparticles have uniform sizes and are finely dispersed in the PEDOT matrix. The chemical constituents and bonding of these composite nanowires are characterized by energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, which indicate that the formation and dispersion of these MnO2 nanoparticles into the nanoscale pores of the PEDOT nanowires are most likely triggered by the reduction of KMnO4 via the redox exchange of permanganate ions with the functional group on PEDOT. Varying the concentrations of KMnO4 and the reaction time controls the loading amount and size of the MnO2 nanoparticles. Cyclic voltammetry and galvanostatic charge-discharge are used to characterize the electrochemical properties of these MnO2 nanoparticle loaded PEDOT nanowires. Due to their extremely high exposed surface area with nanosizes, the pristine MnO2 nanoparticles in these MnO2 nanoparticle enriched PEDOT nanowires show very high specific capacitance (410 F/g) as the supercapacitor electrode materials as well as high Li+ storage capacity (300 mAh/g) as cathode materials of Li ion battery, which boost the energy storage capacity of PEDOT nanowires to 4 times without causing excessive volume expansion in the polymer. The highly conductive and porous PEDOT matrix facilitates fast charge/discharge of the MnO2 nanoparticles and prevents them from agglomerating. These synergic properties enable the MnO2 nanoparticle enriched PEDOT nanowires to be promising electrode materials for supercapacitors and lithium ion batteries.

  12. V-groove SnO2 nanowire sensors: fabrication and Pt-nanoparticle decoration

    International Nuclear Information System (INIS)

    Sun, Gun-Joo; Choi, Sun-Woo; Jung, Sung-Hyun; Katoch, Akash; Kim, Sang Sub

    2013-01-01

    Networked SnO 2 nanowire sensors were achieved using the selective growth of SnO 2 nanowires and their tangling ability, particularly on on-chip V-groove structures, in an effort to overcome the disadvantages imposed on the conventional trench-structured SnO 2 nanowire sensors. The sensing performance of the V-groove-structured SnO 2 nanowire sensors was highly dependent on the geometrical dimension of the groove, being superior to those of their conventional trench-structured counterparts. Pt nanoparticles were decorated on the surface of the networked SnO 2 nanowires via γ-ray radiolysis to enhance the sensing performances of the V-groove sensors whose V-groove widths had been optimized. The V-groove-structured Pt-nanoparticle-decorated SnO 2 nanowire sensors exhibited outstanding and reliable sensing capabilities towards toluene and nitrogen dioxide gases, indicating their potential for use as a platform for chemical gas sensors. (paper)

  13. Charged Nanowire-Directed Growth of Amorphous Calcium Carbonate Nanosheets in a Mixed Solvent for Biomimetic Composite Films.

    Science.gov (United States)

    Liu, Yangyi; Liu, Lei; Chen, Si-Ming; Chang, Fu-Jia; Mao, Li-Bo; Gao, Huai-Ling; Ma, Tao; Yu, Shu-Hong

    2018-04-19

    Bio-inspired mineralization is an effective way for fabricating complicated inorganic materials, which inspires us to develop new methods to synthesize materials with fascinating properties. In this article, we report that the charged tellurium nanowires (TeNWs) can be used as bio-macromolecule analogues to direct the formation of amorphous calcium carbonate (ACC) nanosheets (ACCNs) in a mixed solvent. The effects of surface charges and the concentration of the TeNWs on the formation of ACCNs have been investigated. Particularly, the produced ACCNs can be functionalized by Fe3O4 nanoparticles to produce magnetic ACC/Fe3O4 hybrid nanosheets, which can be used to construct ACC/Fe3O4 composite films through a self-evaporation process. Moreover, sodium alginate-ACC nanocomposite films with remarkable toughness and good transmittance can also be fabricated by using such ACCNs as nanoscale building blocks. This mineralization approach in a mixed solvent using charged tellurium nanowires as bio-macromolecule analogues provides a new way for the synthesis of ACCNs, which can be used as nanoscale building blocks for fabrication of biomimetic composite films.

  14. A novel application of the CuI thin film for preparing thin copper nanowires

    International Nuclear Information System (INIS)

    Shi Shuo; Sun Jialin; Zhang Jianhong; Cao Yang

    2005-01-01

    We present a novel application of the CuI thin film for preparing thin copper nanowires under a direct current electric field (DCEF). The CuI thin film was used as a medium for transmitting cuprous ions during the growing process of copper nanowires. As electrodes are the source of cuprous ions, high-purity copper films were deposited on both ends of the CuI thin film. At 353 K, under whole solid condition, without any templates, and having applied a DCEF of 1.5x10 4 V/m, cuprous ions were generated at the anode and migrated towards the cathode through the CuI film. At the edge of the cathode, cuprous ions obtained electrons and congregated to form a disordered thin copper nanowires bundle. The SEM images showed that these copper nanowires were from 10 to 20 nm in diameter and several hundred nanometers in length. The effect of the electric field intensity and the growth temperature on the diameter of the nanowires was also studied

  15. 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.

  16. Nanostructured Zn and ZnO nanowire thin films for mechanical and self-cleaning applications

    Energy Technology Data Exchange (ETDEWEB)

    Shaik, Ummar Pasha [Advanced Centre of Research in High Energy Materials, University of Hyderabad, Prof. C R Rao Road, Gachibowli, Hyderabad 500046 (India); Purkayastha, Debarun Dhar, E-mail: ddebarun@yahoo.com [Department of Physics, National Institute of Technology Nagaland, Chumukedima, Dimapur 797103 (India); Krishna, M. Ghanashyam [Advanced Centre of Research in High Energy Materials, University of Hyderabad, Prof. C R Rao Road, Gachibowli, Hyderabad 500046 (India); School of Physics, University of Hyderabad, Prof. C R Rao Road, Gachibowli, Hyderabad 500046 (India); Madhurima, V. [Department of Physics, Central University of Tamil Nadu, Thiruvarur 610004 (India)

    2015-03-01

    Highlights: • Zn metal films were deposited by thermal evaporation, on various substrates. • Upon annealing Zn there is transformation of the Zn nanosheets into ZnO nanowires. • ZnO nanowires are superhydrophobic and exhibit wetting transition on UV exposure. • ZnO will be useful in self-cleaning, mechanical and oxidation resistance surfaces. - Abstract: Nanostructured Zn metal films were deposited by thermal evaporation, on borosilicate glass, Quartz, sapphire, lanthanum aluminate and yttria stabilized zirconia substrates. The as-deposited films are nanocrystalline and show a morphology that consists of triangular nanosheets. The films are hydrophobic with contact angles between 102° and 120° with hardness and Young's modulus between 0.15–0.8 GPa and 18–300 GPa, respectively. Thermal annealing of the films at 500 °C results only in partial oxidation of Zn to ZnO, which indicates good oxidation resistance. Annealing also causes transformation of the Zn nanosheets into ZnO nanowires that are polycrystalline in nature. The ZnO nanowires are superhydrophobic with contact angles between 159° and 162°, contact angle hysteresis between 5° and 10° and exhibit a reversible superhydrophobic–hydrophilic transition under UV irradiation. The nanowires are much softer than the as-deposited Zn metal films, with hardness between 0.02 and 0.4 GPa and Young's modulus between 3 and 35 GPa. The current study thus demonstrates a simple process for fabrication of nanostructured Zn metal films followed by a one-step transformation to nanowires with properties that will be very attractive for mechanical and self-cleaning applications.

  17. Semimetal-semiconductor transitions in bismuth-antimony films and nanowires induced by size quantization

    International Nuclear Information System (INIS)

    Nikolaeva, A.A.; Konopko, L.A.; Grabov, V.M.; Komarov, V.A.; Kablukova, N.; Popov, I.A.

    2013-01-01

    Full text:Single-crystal bismuth films and nanowires undergo a transformation from semimetal to semiconductor (SMSC) thanks to the manifestation of quantum size effects, which modify phonon transport, which may be of practical interest. This effect must be most pronounced in single Bi 1-x Sb x nanostructures in the semimetal phase(x < 0.04) with a minimal overlapping of L and T bands. In this paper we present the experimental results an investigation of the low- temperature electrical transport, thermoelectrical properties, SdH oscillations of BiSb films, grown by vacuum thermal evaporation and nanowires prepared by a modified Ulitovsky - Teilor technique. We confirmed with X-ray diffraction that the trigonal axis were perpendicular to the film plane. The single Bi-2at% Sb nanowires with diameter 100-1000nm were represented single crystals in glass capillary with (1011) orientation along the wire axis. The investigations the Shubnikov de Haas oscillations shows, that overlapping L and-T- bands was in two time smaller, than in pure Bi. The quantum dimensional effect induced SMSC transition is observed in Bi-Sb films and nanowires at the wires diameters up to five times greater, than in pure Bi. That experimental fact on the one site will be allow to go at higher temperatures with the same diameters nanowires, and on the other hand allows to separate effects connected with surface state and QSE. We also discuss the thermoelectric properties for optimizing their performance for certain, such as thermoelectrics.

  18. Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

    KAUST Repository

    Phadke, Sujay

    2011-09-30

    Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ∼5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2-D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter-wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter-wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires. Solution processed Gallium doped ZnO nanowires are aligned on substrates using an innovative shear coating technique. Nanowire alignment has shown improvement in ZnO nanowire transparent electrode conductivity. 2D network simulations in conjunction with electrical measurements have revealed different regimes of operation of nanowire thin films and provided a guideline for improving electrical performance of nanowire electrodes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Excellent field emission properties of vertically oriented CuO nanowire films

    Directory of Open Access Journals (Sweden)

    Long Feng

    2018-04-01

    Full Text Available Oriented CuO nanowire films were synthesized on a large scale using simple method of direct heating copper grids in air. The field emission properties of the sample can be enhanced by improving the aspect ratio of the nanowires just through a facile method of controlling the synthesis conditions. Although the density of the nanowires is large enough, the screen effect is not an important factor in this field emission process because few nanowires sticking out above the rest. Benefiting from the unique geometrical and structural features, the CuO nanowire samples show excellent field emission (FE properties. The FE measurements of CuO nanowire films illustrate that the sample synthesized at 500 °C for 8 h has a comparatively low turn-on field of 0.68 V/μm, a low threshold field of 1.1 V/μm, and a large field enhancement factor β of 16782 (a record high value for CuO nanostructures, to the best of our knowledge, indicating that the samples are promising candidates for field emission applications.

  20. Au nanoparticles decorated SiO2 nanowires by dewetting on curved surfaces: facile synthesis and nanoparticles–nanowires sizes correlation

    International Nuclear Information System (INIS)

    Ruffino, F.; Grimaldi, M. G.

    2013-01-01

    We report a solid-state synthesis for SiO 2 nanowires (NWs) (up to 20 microns in length and from about 40 to about 150 nm in diameter) coated by Au nanoparticles (NPs) (from about 20 to about 80 nm in diameter). This protocol is based on three steps: (1) large area production of very long SiO 2 NWs on a Si surface exploiting a simple Au/Si solid-state reaction at high temperature; (2) coating of the SiO 2 NWs by a Au film of desired thickness using sputtering depositions; and (3) a thermal process to induce a dewetting process of the Au-film coating the SiO 2 NWs to obtain Au NPs on the curved surface of the NWs. The morphology evolution of the SiO 2 NWs was followed, in each step, by scanning electron microscopy analyses. They allowed to correlate the evolution of the NPs size with the NWs sizes for different thicknesses of the starting Au-film coating the NWs and different annealing temperatures of the dewetting process. Some theoretical concepts, related to the dewetting process of a film on a curved surface were used to describe the experimental data. The main advantages of the proposed protocols include: (i) simplicity and low-cost (it is based only on sputtering depositions and thermal processes), and (ii) versatility based on the possibility of tuning Au-film thickness and annealing temperature to tune the NPs–NWs sizes ratio. These advantages can make this technique suitable for the mass production of Au NPs-coated SiO 2 NWs toward applications in electronic devices, biosensors, and nanoscale optical devices

  1. Electrochemically synthesized amorphous and crystalline nanowires: dissimilar nanomechanical behavior in comparison with homologous flat films

    Science.gov (United States)

    Zeeshan, M. A.; Esqué-de Los Ojos, D.; Castro-Hartmann, P.; Guerrero, M.; Nogués, J.; Suriñach, S.; Baró, M. D.; Nelson, B. J.; Pané, S.; Pellicer, E.; Sort, J.

    2016-01-01

    The effects of constrained sample dimensions on the mechanical behavior of crystalline materials have been extensively investigated. However, there is no clear understanding of these effects in nano-sized amorphous samples. Herein, nanoindentation together with finite element simulations are used to compare the properties of crystalline and glassy CoNi(Re)P electrodeposited nanowires (φ ~ 100 nm) with films (3 μm thick) of analogous composition and structure. The results reveal that amorphous nanowires exhibit a larger hardness, lower Young's modulus and higher plasticity index than glassy films. Conversely, the very large hardness and higher Young's modulus of crystalline nanowires are accompanied by a decrease in plasticity with respect to the homologous crystalline films. Remarkably, proper interpretation of the mechanical properties of the nanowires requires taking the curved geometry of the indented surface and sink-in effects into account. These findings are of high relevance for optimizing the performance of new, mechanically-robust, nanoscale materials for increasingly complex miniaturized devices.The effects of constrained sample dimensions on the mechanical behavior of crystalline materials have been extensively investigated. However, there is no clear understanding of these effects in nano-sized amorphous samples. Herein, nanoindentation together with finite element simulations are used to compare the properties of crystalline and glassy CoNi(Re)P electrodeposited nanowires (φ ~ 100 nm) with films (3 μm thick) of analogous composition and structure. The results reveal that amorphous nanowires exhibit a larger hardness, lower Young's modulus and higher plasticity index than glassy films. Conversely, the very large hardness and higher Young's modulus of crystalline nanowires are accompanied by a decrease in plasticity with respect to the homologous crystalline films. Remarkably, proper interpretation of the mechanical properties of the nanowires

  2. Large scale, highly conductive and patterned transparent films of silver nanowires on arbitrary substrates and their application in touch screens

    International Nuclear Information System (INIS)

    Madaria, Anuj R; Kumar, Akshay; Zhou Chongwu

    2011-01-01

    The application of silver nanowire films as transparent conductive electrodes has shown promising results recently. In this paper, we demonstrate the application of a simple spray coating technique to obtain large scale, highly uniform and conductive silver nanowire films on arbitrary substrates. We also integrated a polydimethylsiloxane (PDMS)-assisted contact transfer technique with spray coating, which allowed us to obtain large scale high quality patterned films of silver nanowires. The transparency and conductivity of the films was controlled by the volume of the dispersion used in spraying and the substrate area. We note that the optoelectrical property, σ DC /σ Op , for various films fabricated was in the range 75-350, which is extremely high for transparent thin film compared to other candidate alternatives to doped metal oxide film. Using this method, we obtain silver nanowire films on a flexible polyethylene terephthalate (PET) substrate with a transparency of 85% and sheet resistance of 33 Ω/sq, which is comparable to that of tin-doped indium oxide (ITO) on flexible substrates. In-depth analysis of the film shows a high performance using another commonly used figure-of-merit, Φ TE . Also, Ag nanowire film/PET shows good mechanical flexibility and the application of such a conductive silver nanowire film as an electrode in a touch panel has been demonstrated.

  3. Large scale, highly conductive and patterned transparent films of silver nanowires on arbitrary substrates and their application in touch screens.

    Science.gov (United States)

    Madaria, Anuj R; Kumar, Akshay; Zhou, Chongwu

    2011-06-17

    The application of silver nanowire films as transparent conductive electrodes has shown promising results recently. In this paper, we demonstrate the application of a simple spray coating technique to obtain large scale, highly uniform and conductive silver nanowire films on arbitrary substrates. We also integrated a polydimethylsiloxane (PDMS)-assisted contact transfer technique with spray coating, which allowed us to obtain large scale high quality patterned films of silver nanowires. The transparency and conductivity of the films was controlled by the volume of the dispersion used in spraying and the substrate area. We note that the optoelectrical property, σ(DC)/σ(Op), for various films fabricated was in the range 75-350, which is extremely high for transparent thin film compared to other candidate alternatives to doped metal oxide film. Using this method, we obtain silver nanowire films on a flexible polyethylene terephthalate (PET) substrate with a transparency of 85% and sheet resistance of 33 Ω/sq, which is comparable to that of tin-doped indium oxide (ITO) on flexible substrates. In-depth analysis of the film shows a high performance using another commonly used figure-of-merit, Φ(TE). Also, Ag nanowire film/PET shows good mechanical flexibility and the application of such a conductive silver nanowire film as an electrode in a touch panel has been demonstrated.

  4. Light-induced antifungal activity of TiO{sub 2} nanoparticles/ZnO nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, N. [Nano-Physics Research Lab., Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Abdi, Y., E-mail: y.abdi@ut.ac.ir [Nano-Physics Research Lab., Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Haghighi, F. [Department of Medical Mycology, School of Medical sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2011-09-15

    Antifungal activity of TiO{sub 2}/ZnO nanostructures under visible light irradiation was investigated. A simple chemical method was used to synthesize ZnO nanowires. Zinc acetate dihydrate, Polyvinyl Pyrrolidone and deionized water were used as precursor, capping and solvent, respectively. TiO{sub 2} nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO{sub 2}/ZnO nano-composite has represented the diffraction peaks relating to the crystal planes of the TiO{sub 2} (anatase and rutile) and ZnO. TiO{sub 2}/ZnO nanostructure antifungal effect on Candida albicans biofilms was studied and compared with the activity of TiO{sub 2} nanoparticles and ZnO nanowires. The high efficiency photocatalytic activity of TiO{sub 2} nanoparticles leads to increased antifungal activity of ZnO nanowires. Scanning electron microscope was utilized to study the morphology of the as prepared nanostructures and the degradation of the yeast.

  5. Light-induced antifungal activity of TiO2 nanoparticles/ZnO nanowires

    International Nuclear Information System (INIS)

    Haghighi, N.; Abdi, Y.; Haghighi, F.

    2011-01-01

    Antifungal activity of TiO 2 /ZnO nanostructures under visible light irradiation was investigated. A simple chemical method was used to synthesize ZnO nanowires. Zinc acetate dihydrate, Polyvinyl Pyrrolidone and deionized water were used as precursor, capping and solvent, respectively. TiO 2 nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO 2 /ZnO nano-composite has represented the diffraction peaks relating to the crystal planes of the TiO 2 (anatase and rutile) and ZnO. TiO 2 /ZnO nanostructure antifungal effect on Candida albicans biofilms was studied and compared with the activity of TiO 2 nanoparticles and ZnO nanowires. The high efficiency photocatalytic activity of TiO 2 nanoparticles leads to increased antifungal activity of ZnO nanowires. Scanning electron microscope was utilized to study the morphology of the as prepared nanostructures and the degradation of the yeast.

  6. Fully transparent thin-film transistor devices based on SnO2 nanowires.

    Science.gov (United States)

    Dattoli, Eric N; Wan, Qing; Guo, Wei; Chen, Yanbin; Pan, Xiaoqing; Lu, Wei

    2007-08-01

    We report on studies of field-effect transistor (FET) and transparent thin-film transistor (TFT) devices based on lightly Ta-doped SnO2 nano-wires. The nanowire-based devices exhibit uniform characteristics with average field-effect mobilities exceeding 100 cm2/V x s. Prototype nano-wire-based TFT (NW-TFT) devices on glass substrates showed excellent optical transparency and transistor performance in terms of transconductance, bias voltage range, and on/off ratio. High on-currents and field-effect mobilities were obtained from the NW-TFT devices even at low nanowire coverage. The SnO2 nanowire-based TFT approach offers a number of desirable properties such as low growth cost, high electron mobility, and optical transparency and low operation voltage, and may lead to large-scale applications of transparent electronics on diverse substrates.

  7. Spatially controlled synthesis of silver nanoparticles and nanowires by photosensitized reduction

    Energy Technology Data Exchange (ETDEWEB)

    Jradi, S; Zeng, X H; Plain, J; Royer, P; Bachelot, R; Akil, S [Laboratoire de Nanotechnologie et d' Instrumentation Optique, ICD CNRS FRE 2848, Universite de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes (France); Balan, L; Lougnot, D J; Soppera, O; Vidal, L, E-mail: lavinia.balan@uha.fr [Institut de Science des Materiaux de Mulhouse CNRS LRC 7228, 15 rue Jean Starcky, 68057 Mulhouse (France)

    2010-03-05

    The present paper reports on the spatially controlled synthesis of silver nanoparticles (NPs) and silver nanowires by photosensitized reduction. In a first approach, direct photogeneration of silver NPs at the end of an optical fiber was carried out. Control of both size and density of silver NPs was possible by changing the photonic conditions. In a further development, a photochemically assisted procedure allowing silver to be deposited at the surface of a polymer microtip was implemented. Finally, polymer tips terminated by silver nanowires were fabricated by simultaneous photopolymerization and silver photoreduction. The silver NPs were characterized by UV-visible spectroscopy and scanning electron microscopy.

  8. Ultraviolet photosensors fabricated with Ag nanowires coated with ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Guan-Hung [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Hong, Franklin Chau-Nan, E-mail: hong@mail.ncku.edu.tw [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (China); NCKU Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-11-03

    We have developed a simple low temperature process to coat zinc oxide (ZnO) nanoparticles (NPs) on Ag nanowires (NWs) with well-controlled morphology. Triethanolamine (TEA) was employed to react with zinc acetate (Zn(CH{sub 3}COO){sub 2}) forming ZnO NPs. TEA was also found to enhance the nucleation and binding of ZnO NPs on the Ag nanowire surfaces facilitating a complete coverage of Ag nanowire surfaces with ZnO NPs. The effects of the process parameters including reaction time and reaction temperature were studied. The surfaces of 60 nm diameter Ag NWs could be completely covered with ZnO NPs with the final diameters of Ag-NWs@ZnO (core–shell NWs) turning into the range from 100 nm to 450 nm. The Ag-NWs@ZnO was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping analysis, X-ray diffraction, and photoluminescence spectra. Finally, ultraviolet (UV) photosensors were fabricated using Ag-NWs@ZnO. They were found to improve photosensitivity with greatly enhanced fast response by reducing the recovery time by 2 orders, in comparison with the UV-sensors using single-crystalline ZnO NWs. - Highlights: • Solution process to coat ZnO nanoparticles on Ag nanowires has been developed. • Ultraviolet photosensing of ZnO nanoparticles coated on the Ag nanowires was found. • High defect concentration of ZnO nanoparticles enhanced the photosensing properties.

  9. Preparation and Properties of Silver Nanowire-Based Transparent Conductive Composite Films

    Science.gov (United States)

    Tian, Ji-Li; Zhang, Hua-Yu; Wang, Hai-Jun

    2016-06-01

    Silver nanowire-based transparent conductive composite films with different structures were successfully prepared using various methods, including liquid polyol, magnetron sputtering and spin coating. The experimental results revealed that the optical transmittance of all different structural composite films decreased slightly (1-3%) compared to pure films. However, the electrical conductivity of all composite films had a great improvement. Under the condition that the optical transmittance was greater than 78% over the wavelength range of 400-800 nm, the AgNW/PVA/AgNW film became a conductor, while the AZO/AgNW/AZO film and the ITO/AgNW/ITO film showed 88.9% and 94% reductions, respectively, for the sheet resistance compared with pure films. In addition, applying a suitable mechanical pressure can improve the conductivity of AgNW-based composite films.

  10. Multicolor emission from large-area porous thin films constructed of nanowires of small organic molecules

    International Nuclear Information System (INIS)

    Wang Zhechen; Ding Xunlei; Ma Yanping; Xue Wei; He Shenggui; Xiao Wenchang

    2008-01-01

    We describe a facile low-temperature physical vapor deposition approach to fabricate porous network thin films constructed of nanowires of small organic molecules on a large area. Supermolecular assemblies of pyrene nanowires based on a combination of van der Waals forces and π-π stacking tend to hierarchically self-assemble to form uniform porous films using our techniques. The morphology of the films is studied and we also study several reasons influencing the process of assembly such as evaporation temperature, deposition temperature, and different kinds of substrate. The deposition temperature is determined to be the main reason for hierarchical aggregation. Typically prepared films exhibit unique optical properties, that is, multicolor red-green-blue emissions. This novel method can be applied to other organic molecular systems and may be potentially used to place nanoscaled building blocks directly on solid surfaces for fabricating large-area nanostructure-based flat screens.

  11. Multicolor emission from large-area porous thin films constructed of nanowires of small organic molecules

    Science.gov (United States)

    Wang, Zhe-Chen; Xiao, Wen-Chang; Ding, Xun-Lei; Ma, Yan-Ping; Xue, Wei; He, Sheng-Gui

    2008-12-01

    We describe a facile low-temperature physical vapor deposition approach to fabricate porous network thin films constructed of nanowires of small organic molecules on a large area. Supermolecular assemblies of pyrene nanowires based on a combination of van der Waals forces and π-π stacking tend to hierarchically self-assemble to form uniform porous films using our techniques. The morphology of the films is studied and we also study several reasons influencing the process of assembly such as evaporation temperature, deposition temperature, and different kinds of substrate. The deposition temperature is determined to be the main reason for hierarchical aggregation. Typically prepared films exhibit unique optical properties, that is, multicolor red-green-blue emissions. This novel method can be applied to other organic molecular systems and may be potentially used to place nanoscaled building blocks directly on solid surfaces for fabricating large-area nanostructure-based flat screens.

  12. Facile synthesis of palladium nanoparticle doped polyaniline nanowires in soft templates for catalytic applications

    Science.gov (United States)

    Kshirasagar, Krushna J.; Markad, Uddhav S.; Saha, Abhijit; Sharma, Kiran Kumar K.; Sharma, Geeta K.

    2017-02-01

    Palladium nanoparticles doped polyaniline (Pd-PANI) nanocomposite (NCs) is synthesized in surfactant based liquid crystalline mesophase by chemical oxidation followed by radiolysis. The confinement of the liquid crystalline mesophase facilitates polymerization of aniline monomers and their 1D growth into polyaniline (PANI) nanowires by using ammonium persulfate. The PANI nanowires have an average diameter of 30-40 nm. The in situ radiolytic reduction of palladium ions ensures uniform size distribution of the palladium (Pd) nanoparticles on the surface of the PANI nanowires. The synthesized Pd-PANI nanocomposites show wire like structures of PANI (diameter ~30-40 nm) on which Pd nanoparticles of the size 10 nm are decorated. The identical average diameter of the PANI nanowires before and post gamma irradiation suggest high stability of the PANI nanowires in liquid crystalline mesophase. Surface characterization of the NCs were carried out using BET and XPS. The catalytic activity of Pd-PANI NCs are investigated in the reduction of methylene blue (MB) and 4-nitro phenol (4-NP) by sodium borohydride (NaBH4). The kinetics of the Pd-PANI NCs catalysed reactions are analysed using the Langmuir-Hinshelwood model. The apparent rate constant (k app) for the MB and 4-NP reduction reactions is 29  ×  10-3 s-1 and 20  ×  10-3 s-1 respectively with an actual Pd catalyst loading of 2.665  ×  10-4 ppm. Further, the recyclability of the Pd-PANI NCs catalyst in both the reduction reactions shows the stability of the catalyst up to four reaction cycles tested in this investigation and the multifunctional nature of the catalyst. The study provides a new approach for the directional synthesis of conducting polymer-metal nanocomposites and their possible application as a nanocatalyst in environmental remediation.

  13. Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles

    Science.gov (United States)

    Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

    2018-06-01

    Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

  14. Two steps hydrothermal growth and characterisations of BaTiO3 films composed of nanowires

    Science.gov (United States)

    Zawawi, Che Zaheerah Najeehah Che Mohd; Salleh, Shahril; Oon Jew, Lee; Tufail Chaudhary, Kashif; Helmi, Mohamad; Safwan Aziz, Muhammad; Haider, Zuhaib; Ali, Jalil

    2018-05-01

    Barium titanate (BaTiO3) films composed of nanowires have gained considerable research interest due to their lead-free composition and strong energy conversion efficiency. BaTiO3 films can be developed with a simple two steps hydrothermal reactions, which are low cost effective. In this research, BaTiO3 films were fabricated on titanium foil through two steps hydrothermal method namely, the growth of TiO2 and followed by BaTiO3 films. The structural evolutions and the dielectric properties of the films were investigated as well. The structural evolutions of titanium dioxide (TiO2) and BaTiO3 nanowires were characterized using X-ray diffraction and scanning electron microscopy. First step of hydrothermal reaction, TiO2 nanowires were prepared in varied temperatures of 160 °C, 200 °C and 250 °C respectively. Second step of hydrothermal reaction was performed to produce a layer of BaTiO3 films.

  15. Spectroscopic ellipsometry study of FePt nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [School of Materials Science and Technology, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2006-12-15

    The optical properties of a FePt nanoparticle film were investigated using spectroscopic ellipsometry. The FePt nanoparticle film of thickness about 15 nm was prepared by deposition of FePt nanoparticles directly on a Si substrate. The nanoparticle film was annealed at 600 C in vacuum for two hours before the measurements. The optical properties of the FePt nanoparticle film showed distinctively different spectra from those obtained from the bulk and thin film FePt samples, in particular in the low photon energy range (below 3.5 eV) where the nanoparticle film exhibited a relatively flat refractive index and a substantially lower extinction coefficient than the bulk and epitaxial thin film samples. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. ZnTe Amorphous Semiconductor Nanowires Array Electrodeposited into Polycarbonate Membrane Thin Films

    International Nuclear Information System (INIS)

    Ohgai, T; Ikeda, T; Ohta, J

    2013-01-01

    ZnTe amorphous semiconductor nanowires array was electrodeposited into the nanochannels of ion-track etched polycarbonate membrane thin films from acidic aqueous solution at 313 K. ZnTe electrodeposits with Zn-rich composition was obtained over the wide range of cathode potential from −0.8 V to −1.1 V and the growth rate of ZnTe amorphous nanowires was around 3 nm.sec −1 at the cathode potential of −0.8 V. Cylindrical shape of the nanowires was precisely transferred from the nanochannels and the aspect ratio reached up to ca. 40. ZnTe amorphous phase electrodeposited at 313 K was crystallized by annealing at 683 K and the band gap energy of ZnTe crystalline phase reached up to ca. 2.13 eV.

  17. Efficiency enhancement of dye-sensitized solar cells by optimization of electrospun ZnO nanowire/nanoparticle hybrid photoanode and combined modification

    International Nuclear Information System (INIS)

    Song, Lixin; Du, Pingfan; Xiong, Jie; Ko, Frank; Cui, Can

    2015-01-01

    ZnO nanoparticles (ZNPs) and ZnO nanowires (ZNWs) were fabricated via electrospinning and calcination. The ZNPs and ZNWs were blended with different mass ratio by varying ZNWs from 0% to 100% and serviced as photoanodic film of dye-sensitized solar cells (DSSCs) via spin coating. The efficiency of these DSSCs reached a maximum of 2.6% at 20 wt% ZNWs. In order to improve the photovoltaic properties of ZNWs/ZNPs hybrid photoanodic film, the ZNWs/ZNPs hybrid film was modified by the incorporation of multi-walled carbon nanotubes (MWCNTs) into ZnO matrix including both ZNPs and ZNWs combined with TiCl 4 post-treatment. As a result, the efficiency of DSSCs increased from 2.6% to 3.8%, which is mainly attributed to the increased dye loading, faster electron transport, and less electron loss

  18. Hydrothermal growth of highly textured BaTiO3 films composed of nanowires

    International Nuclear Information System (INIS)

    Zhou Zhi; Tang Haixiong; Sodano, Henry A; Lin Yirong

    2013-01-01

    Textured barium titanate (BaTiO 3 ) films are attracting immense research interest due to their lead-free composition and excellent piezoelectric and dielectric properties. Most synthesis methods for these films require a high temperature, leading to the formation of a secondary phase and an overall decrease in the electrical properties of the ceramic. In order to alleviate these issues, a novel fabrication method is introduced by transferring oriented rutile TiO 2 nanowires to a textured BaTiO 3 film at temperatures below 160 °C. The microstructure and thickness of the fabricated BaTiO 3 films were characterized by scanning electron microscopy, and the crystal structure and degree of orientation were evaluated by x-ray diffraction patterns using the Lotgering method. It is shown that the thickness of the BaTiO 3 film can be controlled by the length of TiO 2 nanowire array template, and the degree of orientation of the textured BaTiO 3 films is highly dependent on the film thickness; the crystallographic orientation has been measured to reach up to 87%. The relative dielectric constant (ε r = 1300) and ferroelectric properties (P r = 2.7 μC cm −2 , E c = 4.0 kV mm −1 ) of the textured BaTiO 3 films were also characterized to demonstrate their potential application in sensors, random access memory, and micro-electromechanical systems. (paper)

  19. Au nanoparticles films used in biological sensing

    International Nuclear Information System (INIS)

    Rosales Perez, M; Delgado Macuil, R; Rojas Lopez, M; Gayou, V L; Sanchez Ramirez, J F

    2009-01-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm -1 due to surface enhancement infrared absorption.

  20. Au nanoparticles films used in biological sensing

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Perez, M; Delgado Macuil, R; Rojas Lopez, M; Gayou, V L [Centro de Investigacion en BiotecnologIa Aplicada del IPN, Tepetitla Tlaxcala Mexico C.P. 90700 (Mexico); Sanchez Ramirez, J F, E-mail: mrosalespe@ipn.m [CICATA Legaria Instituto Politecnico Nacional, Mexico Distrito Federal (Mexico)

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm{sup -1} due to surface enhancement infrared absorption.

  1. Blue electroluminescence nanodevice prototype based on vertical ZnO nanowire/polymer film on silicon substrate

    International Nuclear Information System (INIS)

    He Ying; Wang Junan; Chen Xiaoban; Zhang Wenfei; Zeng Xuyu; Gu Qiuwen

    2010-01-01

    We present a polymer-complexing soft template technique to construct the ZnO-nanowire/polymer light emitting device prototype that exhibits blue electrically driven emission with a relatively low-threshold voltage at room temperature in ambient atmosphere, and the ZnO-nanowire-based LED's emission wavelength is easily tuned by controlling the applied-excitation voltage. The nearly vertically aligned ZnO-nanowires with polymer film were used as emissive layers in the devices. The method uses polymer as binder in the LED device and dispersion medium in the luminescence layer, which stabilizes the quasi-arrays of ZnO nanowires embedding in a thin polymer film on silicon substrate and passivates the surface of ZnO nanocrystals, to prevent the quenching of luminescence. Additionally, the measurements of electrical properties showed that ZnO-nanowire/polymer film could significantly improve the conductivity of the film, which could be attributed to an increase in both Hall mobility and carrier concentration. The results indicated that the novel technique is a low-cost process for ZnO-based UV or blue light emission and reduces the requirement for achieving robust p-doping of ZnO film. It suggests that such ZnO-nanowire/polymer-based LEDs will be suitable for the electro-optical application.

  2. Preparation of smooth, flexible and stable silver nanowires- polyurethane composite transparent conductive films by transfer method

    Science.gov (United States)

    Bai, Shengchi; Wang, Haifeng; Yang, Hui; Zhang, He; Guo, Xingzhong

    2018-02-01

    Silver nanowires (AgNWs)-polyurethane (PU) composite transparent conductive films were fabricated via transfer method using AgNWs conductive inks and polyurethane as starting materials, and the effects of post-treatments including heat treatment, NaCl solution bath and HCl solution bath for AgNWs film on the sheet resistance and transmittance of the composite films were respectively investigated in detail. AgNWs networks are uniformly embedded in the PU layer to improve the adhesion and reduce the surface roughness of AgNWs-PU composite films. Heat treatment can melt and weld the nanowires, and NaCl and HCl solution baths promote the dissolution and re-deposition of silver and the dissolving of the polymer, both which form conduction pathways and improve contact of AgNWs for reducing the sheet resistance. Smooth and flexible AgNWs-PU composite film with a transmittance of 85% and a sheet resistance of 15 Ω · sq‑1 is obtained after treated in 0.5 wt% HCl solution bath for 60 s, and the optoelectronic properties of the resultant composite film can maintain after 1000 cycles of bending and 100 days.

  3. Directed deposition of silicon nanowires using neopentasilane as precursor and gold as catalyst

    Directory of Open Access Journals (Sweden)

    Britta Kämpken

    2012-07-01

    Full Text Available In this work the applicability of neopentasilane (Si(SiH34 as a precursor for the formation of silicon nanowires by using gold nanoparticles as a catalyst has been explored. The growth proceeds via the formation of liquid gold/silicon alloy droplets, which excrete the silicon nanowires upon continued decomposition of the precursor. This mechanism determines the diameter of the Si nanowires. Different sources for the gold nanoparticles have been tested: the spontaneous dewetting of gold films, thermally annealed gold films, deposition of preformed gold nanoparticles, and the use of “liquid bright gold”, a material historically used for the gilding of porcelain and glass. The latter does not only form gold nanoparticles when deposited as a thin film and thermally annealed, but can also be patterned by using UV irradiation, providing access to laterally structured layers of silicon nanowires.

  4. Tunable field emission characteristics of ZnO nanowires coated with varied thickness of lanthanum boride thin films

    International Nuclear Information System (INIS)

    Zhao, C.X.; Li, Y.F.; Chen, Jun; Deng, S.Z.; Xu, N.S.

    2013-01-01

    Lanthanum boride (LaB x ) thin films with various thicknesses were deposited on ZnO nanowire arrays by electron beam evaporation. Field emission characteristics of ZnO nanowires show close dependence on LaB x coating thickness. The turn-on field increases with increasing LaB x coating thickness from 10 nm to 50 nm. The observed phenomena were explained by a model that the tunneling at ZnO/LaB x interface dominates the emission process. - Highlights: ► Coating thickness dependence of field emission characteristics of ZnO nanowires was observed from LaB x coated ZnO nanowires. ► More stable field emission was observed from ZnO nanowires with LaB x coating. ► A model was proposed that the tunneling at ZnO/LaB x interface dominates the emission process

  5. Cellular Internalization and Biocompatibility of Periodic Mesoporous Organosilica Nanoparticles with Tunable Morphologies: From Nanospheres to Nanowires

    KAUST Repository

    Fatieiev, Yevhen

    2017-01-10

    This work describes the sol-gel syntheses of para-substituted phenylene-bridged periodic mesoporous organosilica (PMO) nanoparticles (NPs) with tunable morphologies ranging from nanowires to nanospheres. The findings show the key role of the addition of organic co-solvents in the aqueous templates on the final morphologies of PMO NPs. Other factors such as the temperature, the stirring speed, and the amount of organic solvents also influence the shape of PMO NPs. The tuning of the shape of the PMO nanomaterials made it possible to study the influence of the particle morphology on the cellular internalization and biocompatibility.

  6. 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].

  7. Seed-mediated shape evolution of gold nanomaterials: from spherical nanoparticles to polycrystalline nanochains and single-crystalline nanowires

    International Nuclear Information System (INIS)

    Qiu Penghe; Mao Chuanbin

    2009-01-01

    We studied the kinetics of the reduction of a gold precursor (HAuCl 4 ) and the effect of the molar ratio (R) of sodium citrate, which was introduced from a seed solution, and the gold precursor on the shape evolution of gold nanomaterials in the presence of preformed 13 nm gold nanoparticles as seeds. The reduction of the gold precursor by sodium citrate was accelerated due to the presence of gold seeds. Nearly single-crystalline gold nanowires were formed at a very low R value (R = 0.16) in the presence of the seeds as a result of the oriented attachment of the growing gold nanoparticles. At a higher R value (R = 0.33), gold nanochains were formed due to the non-oriented attachment of gold nanoparticles. At a much higher R value (R = 1.32), only larger spherical gold nanoparticles grown from the seeds were found. In the absence of gold seeds, no single-crystalline nanowires were formed at the same R value. Our results indicate that the formation of the 1D nanostructures (nanochains and nanowires) at low R values is due to the attachment of gold nanoparticles along one direction, which is driven by the surface energy reduction, nanoparticle attraction, and dipole-dipole interaction between adjacent nanoparticles.

  8. Optical properties of monodispersive FePt nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [Center for Sustainable Environmental Technologies, Iowa State University, Ames, IA 50011 (United States)

    2004-10-01

    The optical properties of monodispersive FePt nanoparticle films were investigated using spectroscopic ellipsometry in the energy range of 1.5 to 5.5 eV. The monodispersive FePt nanoparticle film was stabilized on a Si substrate by means of an organosilane coupling film, resulting in the formation of a (Si/SiO{sub 2}/APTS/FePt nanoparticles monolayer) structure. Multilayer optical models were employed to study the contribution of the FePt nanoparticles to the measured optical properties of the monodispersive FePt nanoparticle film, and to estimate the optical properties of the FePt nanoparticle layer. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Multilayered films of cobalt oxyhydroxide nanowires/manganese oxide nanosheets for electrochemical capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Huajun [State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014 (China); ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering and AIBN, The University of Queensland, St Lucia, Brisbane, QLD 4072 (Australia); Tang, Fengqiu; Mukherji, Aniruddh; Yan, Xiaoxia; Wang, Lianzhou (Max) Lu, Gao Qing [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering and AIBN, The University of Queensland, St Lucia, Brisbane, QLD 4072 (Australia); Lim, Melvin [Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore)

    2010-01-15

    Multilayered films of cobalt oxyhydroxide nanowires (CoOOHNW) and exfoliated manganese oxide nanosheet (MONS) are fabricated by potentiostatic deposition and electrostatic self-assembly on indium-tin oxide coated glass substrates. The morphology and chemical composition of these films are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectra (XPS) and the potential application as electrochemical supercapacitors are investigated using cyclic voltammetry and charge-discharge measurements. These ITO/CoOOHNW/MONS multilayered film electrodes exhibit excellent electrochemical capacitance properties, including high specific capacitance (507 F g{sup -1}) and long cycling durability (less 2% capacity loss after 5000 charge/discharge cycles). These characteristics indicate that these newly developed films may find important application for electrochemical capacitors. (author)

  10. Highly flexible transparent thin film heaters based on silver nanowires and aluminum zinc oxides

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Hahn-Gil; Kim, Jin-Hoon; Song, Jun-Hyuk; Jeong, Unyong; Park, Jin-Woo, E-mail: jwpark09@yonsei.ac.kr

    2015-08-31

    In this work, we developed highly flexible transparent film heaters (f-TFHs) composed of Ag nanowire networks (AgNWs) and aluminum zinc oxide (AZO). Uniform AgNWs were roll-to-roll coated on polyethylene terephthalate (PET) substrates using the Mayer rod method, and AZO was sputter-deposited atop the AgNWs at room temperature. The sheet resistance (R{sub s}) and transparency (T{sub opt}) of the AZO-coated AgNWs changed only slightly compared with the uncoated AgNWs. AZO is thermally less conductive than the heat pipes, but increases the thermal efficiency of the heaters blocking the heat convection through the air. Based on Joule heating, a higher average film temperature (T{sub ave}) is attained at a fixed electric potential drop between electrodes (ϕ) as the R{sub s} of the film decreases. Our experimental results revealed that T{sub ave} of the hybrid f-TFH is higher than AgNWs when the ratio of the area coverage of AgNWs to AZO is over a certain value. When a ϕ as low as 3 V/cm was applied to 5 cm × 5 cm f-TFHs, the maximum temperature of the hybrid film was over 100 °C, which is greater than that of AgNWs by more than 30 °C. Furthermore, uniform heating throughout the surfaces is achieved in the hybrid films while heating begins in small areas where densities of the nanowires (NWs) are the highest in the bare network. The non-uniform heating decreases the lifetime of f-TFHs by forming hot spots. Cyclic bending test results indicated that the hybrid films were as flexible as the AgNWs, and the R{sub s} of the hybrid films changes only slightly until 5000 cycles. Combined with the high-throughput coating technology presented here, the hybrid films will provide a robust and scalable strategy for large-area f-TFHs with highly enhanced performance. - Highlights: • We developed highly efficient flexible thin film heaters based on Ag nanowires and AZO composites. • In the composite, AZO plays an important role as an insulation blanket to block heat loss to

  11. Thermal Analysis of Sintered Silver Nanoparticles Film

    Directory of Open Access Journals (Sweden)

    M. Keikhaie

    2014-07-01

    Full Text Available Thin bonded films have many applications in antireflection and reflection coating, insulating and conducting films and semiconductor industries. Thermal conductivity is one of the most important parameter for power packaging since the thermal resistance of the interconnections is directly related to the heat removal capability and thermal management of the power package. The defects in materials play very important role on the effective thermal conductivity. In this paper, finite element method (FEM was utilized to simulate the effect of pores on the effective thermal conductivity of sintered silver nanoparticles film. The simulation results indicate that the effective thermal conductivity of film is different at different directions and would be enhanced when the pore angle is 90. The simulation results will help us to further understand the heat transfer process across highly porous structures and will provide us a powerful guide to design coating with high thermal insulation or conductor property. Because of there is no similar experimental data for this simulation results, this paper is a comparative work among three different models.

  12. Catalytic Activity of Silicon Nanowires Decorated with Gold and Copper Nanoparticles Deposited by Pulsed Laser Ablation

    Directory of Open Access Journals (Sweden)

    Michele Casiello

    2018-01-01

    Full Text Available Silicon nanowires (SiNWs decorated by pulsed laser ablation with gold or copper nanoparticles (labeled as AuNPs@SiNWs and CuNPs@SiNWs were investigated for their catalytic properties. Results demonstrated high catalytic performances in the Caryl–N couplings and subsequent carbonylations for gold and copper catalysts, respectively, that have no precedents in the literature. The excellent activity, attested by the very high turn over number (TON values, was due both to the uniform coverage along the NW length and to the absence of the chemical shell surrounding the metal nanoparticles (MeNPs. A high recyclability was also observed and can be ascribed to the strong covalent interaction at the Me–Si interface by virtue of metal “silicides” formation.

  13. Enhanced vapour sensing using silicon nanowire devices coated with Pt nanoparticle functionalized porous organic frameworks

    KAUST Repository

    Cao, Anping

    2018-03-09

    Recently various porous organic frameworks (POFs, crystalline or amorphous materials) have been discovered, and used for a wide range of applications, including molecular separations and catalysis. Silicon nanowires (SiNWs) have been extensively studied for diverse applications, including as transistors, solar cells, lithium ion batteries and sensors. Here we demonstrate the functionalization of SiNW surfaces with POFs and explore its effect on the electrical sensing properties of SiNW-based devices. The surface modification by POFs was easily achieved by polycondensation on amine-modified SiNWs. Platinum nanoparticles were formed in these POFs by impregnation with chloroplatinic acid followed by chemical reduction. The final hybrid system showed highly enhanced sensitivity for methanol vapour detection. We envisage that the integration of SiNWs with POF selector layers, loaded with different metal nanoparticles will open up new avenues, not only in chemical and biosensing, but also in separations and catalysis.

  14. Piezoresistive Pressure Sensor Based on Synergistical Innerconnect Polyvinyl Alcohol Nanowires/Wrinkled Graphene Film.

    Science.gov (United States)

    Liu, Weijie; Liu, Nishuang; Yue, Yang; Rao, Jiangyu; Cheng, Feng; Su, Jun; Liu, Zhitian; Gao, Yihua

    2018-04-01

    Piezoresistive sensor is a promising pressure sensor due to its attractive advantages including uncomplicated signal collection, simple manufacture, economical and practical characteristics. Here, a flexible and highly sensitive pressure sensor based on wrinkled graphene film (WGF)/innerconnected polyvinyl alcohol (PVA) nanowires/interdigital electrodes is fabricated. Due to the synergistic effect between WGF and innerconnected PVA nanowires, the as-prepared pressure sensor realizes a high sensitivity of 28.34 kPa -1 . In addition, the device is able to discern lightweight rice about 22.4 mg (≈2.24 Pa) and shows excellent durability and reliability after 6000 repeated loading and unloading cycles. What is more, the device can detect subtle pulse beat and monitor various human movement behaviors in real-time. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Efficient photocatalytic performance enhancement in Co-doped ZnO nanowires coupled with CuS nanoparticles

    Science.gov (United States)

    Li, Wei; Wang, Guojing; Feng, Yimeng; Li, Zhengcao

    2018-01-01

    In this research, a kind of highly efficient semiconductor photocatalyst was fabricated by depositing CuS nanoparticles uniformly on the surface of Co-doped ZnO nanowires. ZnO nanowires were synthesized by hydrothermal method and CuS nanoparticles were modified by successive ionic layer adsorption and reaction (SILAR). By conducting methyl orange (MO) degradation experiments under the illumination of visible light, the photocatalytic activity of Co-doped ZnO nanowires modified with CuS nanoparticles was found to be nearly three times active when compared to bare ZnO nanowires. Its superior photocatalytic performance has two main reasons. The doped Co2+ ions can inhibit the recombination of photo-generated electron-hole pairs and decrease the optical bandgap, while the p-n heterostructure can enhance the visible light absorption ability and promote the separation of photo-excited charge carriers. Furthermore, the effect of the amount of deposited CuS nanoparticles on the photocatalysis was also investigated. The photocatalytic efficiency firstly raised along with the increment of SILAR cycle times and reached a maximum at 10 cycles but then decreased as the cycle times continue to increase. This originates from that an excessive amount of CuS would not only cover the active reacting sites, but also serve as recombination centers. Overall, this new nanostructure is expected to work as an efficient photocatalyst.

  16. Controlled Synthesis of Sb 2 O 3 Nanoparticles, Nanowires, and Nanoribbons

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Sb 2 O 3 nanoparticles, nanowires, and nanoribbons have been selectively synthesized in a controlled manner under mild conditions by using CTAB as a soft template. By adopting Sb ( OH 4 − as an inorganic precursor and the concentration of CTAB as an adjusting parameter, morphologies of Sb 2 O 3 nanostructures can be selectively controlled. Typically, C CTAB <0.15 mmol favors the formation of nanoparticles (product one or short form P1; when the concentration of CATB is in the range 0.15–2.0 mmol, nanowires (P2 dominate the products; nanoribbons (P3 form above the concentration of 2.0 mmol, and when the concentration of CTAB goes further higher, treelike bundles of nanoribbons could be achieved. The method in the present study has potential advantages of easy handling, relatively low-cost, and large-scale production. The facile and large-scale synthesis of varied Sb 2 O 3 nanostructures is believed to be useful for the application of catalysis and flame retardance.

  17. Chemical bath deposition of ZnO nanowire-nanoparticle composite electrodes for use in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ku, C-H; Wu, J-J [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2007-12-19

    ZnO nanowire (NW)-layered basic zinc acetate (LBZA)/ZnO nanoparticle (NP) composite electrodes with different NP occupying extents have been synthesized using a simple wet-chemical route for use in dye-sensitized solar cells (DSSCs). By employing mercurochrome as the sensitizer, superior efficiencies ({eta}) of 1.27-2.37% are obtained using the ZnO NW-LBZA/ZnO NP composite electrodes composed of a 5.5 {mu}m thick NW array with different NP occupying extents in comparison with the ZnO NW DSSC ({eta} = 0.45%). It suggests that the ZnO NW-LBZA/ZnO NP composite films which possess a considerable enlarged surface area by NPs growth, without sacrificing electron transport efficiency of single-crystalline ZnO NWs at the same time, are promising photoanodes for use in DSSCs. In addition to the extent of NP occupation, the overall efficiency of the ZnO NW-LBZA/ZnO NP composite DSSC is also influenced by the thickness of the composite film as well as the LBZA fraction and the cracks within the composite. The fraction of LBZA affected by the NP growth period and post-annealing conditions is found to play a crucial role in electron transport through the composite anode. Up to now, a high efficiency DSSC of 3.2% is achieved using a mercurochrome-sensitized and 6.2 {mu}m thick NW-NP composite film.

  18. A Facile Method for Preparing Transparent, Conductive, and Paper-Like Silver Nanowire Films

    Directory of Open Access Journals (Sweden)

    Yajie Wang

    2011-01-01

    Full Text Available Transparent, conductive, and flexible silver nanowire (AgNW films have been fabricated by a facile two-step method. Firstly, the well-dispersed AgNW suspension is vacuum filtered using mixed esters of cellulose (MCE membranes as filters. Then, the AgNW-MCE films are treated with acetone vapor. After the infiltration of acetone vapor, the white and porous MCE membranes change into transparent and pore-free, and AgNW-MCE films are obtained with extraordinary optical, conductive, and mechanical properties. An optimal result is obtained with transmittance of 85% at 550 nm and sheet resistance about 50 Ohm/sq. The flexibility of AgNW-MCE films is remarkable, which is comparable to that of the AgNW film on flexible polyethylene terephthalate (PET. More important, AgNW-MCE films show an excellent adhesion to the substrate, which causes a stable electrical conductivity even after scotch tape test and finger friction test. As a result of improved adhesion to the substrate, the sheet resistance of AgNW-MCE films is about 20% smaller than that of AgNW-PET films.

  19. A sensitive DNA biosensor fabricated from gold nanoparticles, carbon nanotubes, and zinc oxide nanowires on a glassy carbon electrode

    International Nuclear Information System (INIS)

    Wang Jie; Li Shuping; Zhang Yuzhong

    2010-01-01

    We outline here the fabrication of a sensitive electrochemical DNA biosensor for the detection of sequence-specific target DNA. Zinc oxide nanowires (ZnONWs) were first immobilized on the surface of a glassy carbon electrode. Multi-walled carbon nanotubes (MWCNTs) with carboxyl groups were then dropped onto the surface of the ZnONWs. Gold nanoparticles (AuNPs) were subsequently introduced to the surface of the MWNTs/ZnONWs by electrochemical deposition. A single-stranded DNA probe with a thiol group at the end (HS-ssDNA) was covalently immobilized on the surface of the AuNPs by forming an Au-S bond. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) were used to investigate the film assembly process. Differential pulse voltammetry (DPV) was used to monitor DNA hybridization by measuring the electrochemical signals of [Ru(NH 3 ) 6 ] 3+ bounding to double-stranded DNA (dsDNA). The incorporation of ZnONWs and MWCNTs in this sensor design significantly enhances the sensitivity and the selectivity. This DNA biosensor can detect the target DNA quantitatively in the range of 1.0 x 10 -13 to 1.0 x 10 -7 M, with a detection limit of 3.5 x 10 -14 M (S/N = 3). In addition, the DNA biosensor exhibits excellent selectivity, even for single-mismatched DNA detection.

  20. Transparent TiO2 nanowire networks via wet corrosion of Ti thin films for dye-sensitized solar cells

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Hong, Jongin

    2017-09-01

    Transparent TiO2 nanowire networks were prepared by corrosion of Ti thin films on F-doped SnO2 glass substrates in an alkaline (potassium hydroxide: KOH) solution. The formation of the porous TiO2 nanostructures from the Ti thin films was thoroughly investigated. Dye-sensitized solar cells with a photoanode of 1.2-μm-thick nanowire networks exhibit an average optical transmittance of 40% in the visible light region and a power conversion efficiency of 1.0% under one sun illumination.

  1. Transparent Electrode Based on Silver Nanowires and Polyimide for Film Heater and Flexible Solar Cell.

    Science.gov (United States)

    He, Xin; Duan, Feng; Liu, Junyan; Lan, Qiuming; Wu, Jianhao; Yang, Chengyan; Yang, Weijia; Zeng, Qingguang; Wang, Huafang

    2017-11-29

    Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53-80% and sheet resistances of 2.8-16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectronic devices, we utilized it in a film heater and a flexible solar cell. The film heater was able to generate a temperature of 58 °C at a driving voltage of 3.5 V within 20 s, indicating its potential application in heating devices that require low power consumption and fast response. The flexible solar cell based on the composite film with a transmittance value of 71% presented a power conversion efficiency of 3.53%. These successful applications proved that the fabricated Ag NWs-PI composite film is a good candidate for application in flexible optoelectronic devices.

  2. Existence, release, and antibacterial actions of silver nanoparticles on Ag–PIII TiO2 films with different nanotopographies

    Directory of Open Access Journals (Sweden)

    Li J

    2014-07-01

    Full Text Available Jinhua Li, Yuqin Qiao, Hongqin Zhu, Fanhao Meng, Xuanyong Liu State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, People’s Republic of China Abstract: Nanotopographical TiO2 films (including nanorod, nanotip, and nanowire topographies were successfully fabricated on the metallic Ti surface via hydrothermal treatment and then underwent Ag plasma immersion ion implantation to incorporate Ag with TiO2. The surface morphology, phase component, and chemical composition before and after Ag–PIII were characterized. In view of the potential clinical applications, both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used to estimate their antimicrobial effect. The nanostructured TiO2 films on a Ti surface exhibit a better bacteriostatic effect on both microbes compared to the pristine Ti. The nanotopographies of the TiO2 films affect the nucleation, growth, and distribution of Ag nanoparticles in the films during Ag–PIII process. The Ag nanoparticles are completely embedded into the nanorod film while partially exposed out of the nanotip and nanowire films, which account for the significant differences in the release behaviors of Ag ions in vitro. However, no significant difference exists in their antimicrobial activity against both microbes. The antimicrobial actions of the Ag@TiO2 system described here consist of two methods – the contact-killing action and the release-killing action. Nevertheless, based on the observed results, the contact-killing action should be regarded as the main method to destroy microbes for all the Ag plasma-modified TiO2 nanofilms. This study provides insight to optimize the surface design of Ti-based implants to acquire more effective antimicrobial surfaces to meet clinical applications. Keywords: silver, nanoparticles, titania, nanostructure, antibacterial, plasma

  3. Copper Nanowires and Their Applications for Flexible, Transparent Conducting Films: A Review

    Directory of Open Access Journals (Sweden)

    Vu Binh Nam

    2016-03-01

    Full Text Available Cu nanowires (NWs are attracting considerable attention as alternatives to Ag NWs for next-generation transparent conductors, replacing indium tin oxide (ITO and micro metal grids. Cu NWs hold great promise for low-cost fabrication via a solution-processed route and show preponderant optical, electrical, and mechanical properties. In this study, we report a summary of recent advances in research on Cu NWs, covering the optoelectronic properties, synthesis routes, deposition methods to fabricate flexible transparent conducting films, and their potential applications. This review also examines the approaches on protecting Cu NWs from oxidation in air environments.

  4. The phonon-assisted tunneling mechanism of conduction in ZnO nanowires and films

    International Nuclear Information System (INIS)

    Pipinys, Povilas; Ohlckers, Per

    2010-01-01

    The phonon-assisted tunneling (PhAT) model is applied for an explanation of the conductivity dependence on temperature and temperature-dependent I-V characteristics measured by other investigators for zinc oxide (ZnO) nanowires and films. Our proposed model describes well not only conductivity dependence on temperature measured in a wide temperature range, but also temperature-dependent I-V data using the same set of parameters characterizing the material under investigation. The values of active phonons energy are estimated from a fit of the conductivity dependence to temperature data with the PhAT theory.

  5. A universal approach to electrically connecting nanowire arrays using nanoparticles—application to a novel gas sensor architecture

    Science.gov (United States)

    Parthangal, Prahalad M.; Cavicchi, Richard E.; Zachariah, Michael R.

    2006-08-01

    We report on a novel, in situ approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles. The utility of the approach is demonstrated by development of a gas sensing device employing this nano-architecture. Well-aligned, single-crystalline zinc oxide nanowires were grown through a direct thermal evaporation process at 550 °C on gold catalyst layers. Electrical contact to the top of the nanowire array was established by creating a contiguous nanoparticle film through electrostatic attachment of conductive gold nanoparticles exclusively onto the tips of nanowires. A gas sensing device was constructed using such an arrangement and the nanowire assembly was found to be sensitive to both reducing (methanol) and oxidizing (nitrous oxides) gases. This assembly approach is amenable to any nanowire array for which a top contact electrode is needed.

  6. 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%)

  7. 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%)

  8. Solution processed zinc oxide nanopyramid/silver nanowire transparent network films with highly tunable light scattering properties

    KAUST Repository

    Mehra, Saahil

    2013-01-01

    Metal nanowire transparent networks are promising replacements to indium tin oxide (ITO) transparent electrodes for optoelectronic devices. While the transparency and sheet resistance are key metrics for transparent electrode performance, independent control of the film light scattering properties is important to developing multifunctional electrodes for improved photovoltaic absorption. Here we show that controlled incorporation of ZnO nanopyramids into a metal nanowire network film affords independent, highly tunable control of the scattering properties (haze) with minimal effects on the transparency and sheet resistance. Varying the zinc oxide/silver nanostructure ratios prior to spray deposition results in sheet resistances, transmission (600 nm), and haze (600 nm) of 6-30 Ω □-1, 68-86%, and 34-66%, respectively. Incorporation of zinc oxide nanopyramid scattering agents into the conducting nanowire mesh has a negligible effect on mesh connectivity, providing a straightforward method of controlling electrode scattering properties. The decoupling of the film scattering power and electrical characteristics makes these films promising candidates for highly scattering transparent electrodes in optoelectronic devices and can be generalized to other metal nanowire films as well as carbon nanotube transparent electrodes. © 2013 The Royal Society of Chemistry.

  9. Comparative analysis of serial and parallel laser patterning of Ag nanowire thin films

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Harim; Lee, Myeongkyu, E-mail: myeong@yonsei.ac.kr

    2017-03-31

    Highlights: • Serial and parallel laser patterning of Ag nanowire thin films is comparatively analyzed. • AgNW film can be directly patterned by a spatially-modulated pulsed Nd:YAG laser beam. • An area of 2.24 cm{sup 2} can be simultaneously patterned by a single pulse with energy of 350 mJ. - Abstract: Ag nanowire (AgNW) films solution-coated on a glass substrate were laser-patterned in two different ways. For the conventional serial process, a pulsed ultraviolet laser of 30 kHz repetition rate and ∼20 ns pulse width was employed as the laser source. For parallel patterning, the film was directly irradiated by a spatially-modulated Nd:YAG laser beam that has a low repetition rate of 10 kHz and a shorter pulse width of 5 ns. While multiple pulses with energy density ranging from 3 to 9 J/cm{sup 2} were required to pattern the film in the serial process, a single pulse with energy density of 0.16 J/cm{sup 2} completely removed AgNWs in the parallel patterning. This may be explained by the difference in patterning mechanism. In the parallel process using short pulses of 5 ns width, AgNWs can be removed in their solid state by the laser-induced thermo-elastic force, while they should be evaporated in the serial process utilizing a high-repetition rate laser. Important process parameters such as threshold energy density, speed, and available feature sizes are comparatively discussed for the two patterning.

  10. Organic vapor discrimination with chemiresistor arrays of temperature modulated tin-oxide nanowires and thiolate-monolayer-protected gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Scholten, K; Bohrer, F I; Dattoli, E; Lu, W; Zellers, E T, E-mail: ezellers@umich.edu [Center for Wireless Integrated Microsystems, University of Michigan, Ann Arbor, MI 48109-2122 (United States)

    2011-03-25

    This paper explores the discrimination of organic vapors with arrays of chemiresistors (CRs) employing interface layers of tin-oxide nanowires (NWs) and thiolate-monolayer-protected gold nanoparticles (MPNs). The former devices use contact-printed mats of NWs on micro-hotplate membranes to bridge a pair of metal electrodes. Oxidation at the NW surface causes changes in charge transport, the temperature dependence of which differs among different vapors, permitting vapor discrimination. The latter devices use solvent cast films of MPNs on interdigital electrodes operated at room temperature. Sorption into the organic monolayers causes changes in film tunneling resistance that differ among different vapors and MPN structures, permitting vapor discrimination. Here, we compare the performance and assess the 'complementarity' of these two types of sensors. Calibrated responses from an NW CR operated at two different temperatures and from a set of four different MPN CRs were generated for three test vapors: n-hexane, toluene, and nitromethane. This pooled data set was then analyzed using principal components regression classification models with varying degrees of random error superimposed on the responses via Monte Carlo simulation in order to estimate the rates of recognition/discrimination for arrays comprising different combinations of sensors. Results indicate that the diversity of most of the dual MPN-CR arrays exceeds that of the dual NW-CR array. Additionally, in assessing all possible arrays of 4-6 CR sensors, the recognition rates of the hybrid arrays (i.e. MPN + NW) were no better than that of the 4-sensor array containing only MPN CRs.

  11. Extraordinary Hall-effect in colloidal magnetic nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Gur, Leah; Tirosh, Einat [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Segal, Amir [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Markovich, Gil, E-mail: gilmar@post.tau.ac.il [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Gerber, Alexander, E-mail: gerber@post.tau.ac.il [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel)

    2017-03-15

    Colloidal nickel nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were synthesized. The nanoparticle dispersions were deposited on substrates and dried under mild heating to form conductive films. The films exhibited very small coercivity, nearly metallic conductivity, and a significant extraordinary Hall effect signal. This method could be useful for preparing simple, printed magnetic field sensors with the advantage of relatively high sensitivity around zero magnetic field, in contrast to magnetoresistive sensors, which have maximal field sensitivity away from zero magnetic field. - Highlights: • Ni nanoparticle ink capable of forming conductive films on drying. • The Ni nanoparticle films exhibit significant extraordinary Hall effect. • This system could be used for preparing printed magnetic field sensors integrated in 3D printed structures.

  12. Nanoparticles doped film sensing based on terahertz metamaterials

    Science.gov (United States)

    Liu, Weimin; Fan, Fei; Chang, Shengjiang; Hou, Jiaqing; Chen, Meng; Wang, Xianghui; Bai, Jinjun

    2017-12-01

    A nanoparticles concentration sensor based on doped film and terahertz (THz) metamaterial has been proposed. By coating the nanoparticles doped polyvinyl alcohol (PVA) film on the surface of THz metamaterial, the effects of nanoparticle concentration on the metamaterial resonances are investigated through experiments and numerical simulations. Results show that resonant frequency of the metamaterial linearly decreases with the increment of doping concentration. Furthermore, numerical simulations illustrate that the redshift of resonance results from the changes of refractive index of the doped film. The concentration sensitivity of this sensor is 3.12 GHz/0.1%, and the refractive index sensitivity reaches 53.33 GHz/RIU. This work provides a non-contact, nondestructive and sensitive method for the detection of nanoparticles concentration and brings out a new application on THz film metamaterial sensing.

  13. Thin films on the basis of magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    G. Alimbekova

    2012-09-01

    Full Text Available The present work is to study the adsorption of magnetic nanoparticles in the structure of nanohybrid films by layer-by-layer (LbL method. Obtained by UV-VIS absorption spectra of 5% magnetic nanoparticles and the aqueous solution polyvinyl alcohol consisting of 5 and 10 nanohybrid layers. Analysis of the optical absorption spectra shows the homogeneity and mechanical stability of the nanohybrid films.

  14. Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

    DEFF Research Database (Denmark)

    Tricoli, Antonio; Elmøe, Tobias Dokkedal

    2012-01-01

    The assembly of nanoparticle films by flame spray pyrolysis (FSP) synthesis and deposition on temperature‐controlled substrates (323–723 K) was investigated for several application‐relevant conditions. An exemplary SnO2 nanoparticle aerosol was generated by FSP and its properties (e.g., particle...

  15. 3D plasmonic transducer based on gold nanoparticles produced by laser ablation on silica nanowires

    Science.gov (United States)

    Gontad, F.; Caricato, A. P.; Manera, M. G.; Colombelli, A.; Resta, V.; Taurino, A.; Cesaria, M.; Leo, C.; Convertino, A.; Klini, A.; Perrone, A.; Rella, R.; Martino, M.

    2016-05-01

    Silica two-dimensional substrates and nanowires (NWs) forests have been successfully decorated with Au nanoparticles (NPs) through laser ablation by using a pulsed ArF excimer laser, for sensor applications. A uniform coverage of both substrate surfaces with NPs has been achieved controlling the number of laser pulses. The annealing of the as-deposited particles resulted in a uniform well-defined distribution of spherical NPs with an increased average diameter up to 25 nm. The deposited samples on silica NWs forest present a very good plasmonic resonance which resulted to be very sensitive to the changes of the environment (ethanol/water solutions with increasing concentration of ethanol) allowing the detection of changes on the second decimal digit of the refractive index, demonstrating its potentiality for further biosensing functionalities.

  16. Rhodium Nanoparticle-mesoporous Silicon Nanowire Nanohybrids for Hydrogen Peroxide Detection with High Selectivity

    Science.gov (United States)

    Song, Zhiqian; Chang, Hucheng; Zhu, Weiqin; Xu, Chenlong; Feng, Xinjian

    2015-01-01

    Developing nanostructured electrocatalysts, with low overpotential, high selectivity and activity has fundamental and technical importance in many fields. We report here rhodium nanoparticle and mesoporous silicon nanowire (RhNP@mSiNW) hybrids for hydrogen peroxide (H2O2) detection with high electrocatalytic activity and selectivity. By employing electrodes that loaded with RhNP@mSiNW nanohybrids, interference caused from both many electroactive substances and dissolved oxygen were eliminated by electrochemical assaying at an optimal potential of +75 mV. Furthermore, the electrodes exhibited a high detection sensitivity of 0.53 μA/mM and fast response (< 5 s). This high-performance nanohybrid electrocatalyst has great potential for future practical application in various oxidase-base biosensors. PMID:25588953

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

    Indian Academy of Sciences (India)

    Thin films of metal-organic compounds and metal nanoparticle-embedded polymers for nonlinear optical applications. S Philip Anthony Shatabdi Porel D ... Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored. A family of zinc complexes which ...

  18. Binary conductive network for construction of Si/Ag nanowires/rGO integrated composite film by vacuum-filtration method and their application for lithium ion batteries

    International Nuclear Information System (INIS)

    Tang, H.; Xia, X.H.; Zhang, Y.J.; Tong, Y.Y.; Wang, X.L.; Gu, C.D.; Tu, J.P.

    2015-01-01

    Construction of high-capacity anode is highly important for the development of next-generation high-performance lithium ion batteries (LIBs). Herein we fabricate Si/Ag nanowires/reduced graphene oxide (Si/Ag NWs/rGO) integrated composite film by introducing binary conductive networks (Ag NWs and rGO) into Si active materials with the help of a facile vacuum-filtration method. Active Si nanoparticles are homogeneously encapsulated by binary Ag NWs-rGO conductive network, in which Ag NWs are interwoven among the rGO sheets. The electrochemical properties of the integrated Si/Ag NWs/rGO composite film are thoroughly characterized as anode of LIBs. Compared to the Si/rGO composite film, the integrated Si/Ag NWs/rGO composite film exhibits enhanced electrochemical performances with higher capacity, better high-rate capability and cycling stability (1269 mAh g"−"1 at 50 mA g"−"1 up to 50 cycles). The binary conductive network plays a positive role in the enhancement of performance due to its faster ion/electron transfer, and better anti-structure degradation caused by volume expansion during the cycling process.

  19. In-situ fabrication of hybrid polyoxometalate nanoparticles composite films

    International Nuclear Information System (INIS)

    Lan Yang; Mao Baodong; Wang Enbo; Song Yonghai; Kang Zhenhui; Wang Chunlei; Tian Chungui; Zhang Chao; Xu Lin; Li Zhuang

    2007-01-01

    Inorganic-organic hybrid nanoparticles multilayer films were fabricated by extending the method of nucleation and growth of particles in polymer assemblies. The polyelectrolyte matrix was constructed by layer-by-layer self-assembly method. Synthesis of polyoxometalate nanoparticles was achieved by alternately dipping the precursor polyelectrolyte matrix into AgNO 3 and H 4 SiW 12 O 40 aqueous solutions. Repeating the above synthesis process, Ag 4 SiW 12 O 40 nanoparticles with controllable diameters of 20 to 77 nm were synthesized in the multilayer films in-situ. UV-vis absorption spectra indicate that the nanoparticles grew gradually in the synthesis process. Transmission electron microscopy was used to observe the size and morphology of the nanoparticles

  20. Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

    International Nuclear Information System (INIS)

    Bohlouli-Zanjani, Golnaz; Wen, John Z.; Hu, Anming; Persic, John; Ringuette, Sophie; Zhou, Y. Norman

    2013-01-01

    Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites

  1. One-step aerosol synthesis of nanoparticle agglomerate films: simulation of film porosity and thickness

    International Nuclear Information System (INIS)

    Maedler, Lutz; Lall, Anshuman A; Friedlander, Sheldon K

    2006-01-01

    A method is described for designing nanoparticle agglomerate films with desired film porosity and film thickness. Nanoparticle agglomerates generated in aerosol reactors can be directly deposited on substrates to form uniform porous films in one step, a significant advance over existing technologies. The effect of agglomerate morphology and deposition mechanism on film porosity and thickness are discussed. Film porosity was calculated for a given number and size of primary particles that compose the agglomerates, and fractal dimension. Agglomerate transport was described by the Langevin equation of motion. Deposition enhancing forces such as thermophoresis are incorporated in the model. The method was validated for single spherical particles using previous theoretical studies. An S-shape film porosity dependence on the particle Peclet number typical for spherical particles was also observed for agglomerates, but films formed from agglomerates had much higher porosities than films from spherical particles. Predicted film porosities compared well with measurements reported in the literature. Film porosities increased with the number of primary particles that compose an agglomerate and higher fractal dimension agglomerates resulted in denser films. Film thickness as a function of agglomerate deposition time was calculated from the agglomerate deposition flux in the presence of thermophoresis. The calculated film thickness was in good agreement with measured literature values. Thermophoresis can be used to reduce deposition time without affecting the film porosity

  2. Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Rion Parsons

    2017-04-01

    Full Text Available The optics of axial silicon nanowire solar cells is investigated and compared to silicon thin-film solar cells with textured contact layers. The quantum efficiency and short circuit current density are calculated taking a device geometry into account, which can be fabricated by using standard semiconductor processing. The solar cells with textured absorber and textured contact layers provide a gain of short circuit current density of 4.4 mA/cm2 and 6.1 mA/cm2 compared to a solar cell on a flat substrate, respectively. The influence of the device dimensions on the quantum efficiency and short circuit current density will be discussed.

  3. Amorphous SiO {sub x} nanowires grown on silicon (100) substrates via rapid thermal process of nanodiamond films

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xingbo [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Wang Lei [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yang Deren [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)]. E-mail: mseyang@zju.edu.cn

    2006-05-01

    Rapid thermal process (RTP) has been carried out on the deposited nanocrystalline diamond (NCD) films. The RTP treatments performed at 800 and 1200 deg. C have been shown to exert prominent influence on the morphology and structure of the NCD films. The loss of material at grain boundaries has been observed at both 800 and 1200 deg. C RTP treatments. Large-scale amorphous SiO {sub x} nanowires with diameters of 30-50 nm and length up to 10 {mu}m were synthesized after RTP treatment at 1200 deg. C for 60 s. The synthesized nanowires were characterized in detail by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction and energy-dispersed X-ray spectrometry analysis. A possible growth mechanism has been proposed to explain the observed phenomenon.

  4. Obtaining and characterization of thin films polyelectrolyte with gold nanoparticles

    International Nuclear Information System (INIS)

    Popiolski, Tatiane M.; Crespo, Janaina S.; Silva, Renato B.

    2011-01-01

    Thin films of polyelectrolytes are manufactured via sequential adsorption of weak polyelectrolytes from aqueous solutions based on electrostatic interaction of oppositely charged polymers. Metal containing polymeric compounds are of particular interest to the production of materials with electrical interface and optical properties. In this sense, the objective of this study was to obtain thin films of weak polyelectrolytes and analyze the distribution of gold nanoparticles stabilized by sodium citrate and by poly (vinylpyrrolidone). The characterization was performed using UV-visible, X-ray diffraction and atomic force microscopy. The techniques of UV-visible and X-ray diffraction was confirmed the presence of gold in the films, the atomic force microscopy images were used to analyze the morphology of the films and check the behavior of the diffusion of gold nanoparticles. (author)

  5. Density control of electrodeposited Ni nanoparticles/nanowires inside porous anodic alumina templates by an exponential anodization voltage decrease.

    Science.gov (United States)

    Marquardt, B; Eude, L; Gowtham, M; Cho, G; Jeong, H J; Châtelet, M; Cojocaru, C S; Kim, B S; Pribat, D

    2008-10-08

    Porous alumina templates have been fabricated by applying an exponential voltage decrease at the end of the anodization process. The time constant η of the exponential voltage function has been used to control the average thickness and the thickness distribution of the barrier layer at the bottom of the pores of the alumina structure. Depending on the η value, the thickness distribution of the barrier layer can be made very uniform or highly scattered, which allows us to subsequently fine tune the electrodeposition yield of nickel nanoparticles/nanowires at low voltage. As an illustration, the pore filling percentage with Ni has been varied, in a totally reproducible manner, between ∼3 and 100%. Combined with the ability to vary the pore diameter and repetition step over ∼2 orders of magnitude (by varying the anodization voltage and electrolyte type), the control of the pore filling percentage with metal particles/nanowires could bring novel approaches for the organization of nano-objects.

  6. Electrochromic properties of self-assembled nanoparticle multilayer films

    International Nuclear Information System (INIS)

    Xue Bo; Li Hong; Zhang Lanlan; Peng Jun

    2010-01-01

    Hexagonal tungsten bronze (HTB) nanocrystal and TiO 2 nanoparticles were assembled into thin films by layer-by-layer self-assembly method. HTB nanocrystals were synthesized by hydrothermal route at 155 o C. UV-Vis spectra showed that the HTB/TiO 2 films exhibit a linear increase in film thickness with assembly exposure steps. The electrochromic property of the film was carefully investigated. Cyclic voltammetry indicated that the redox peak was around -0.5 V. The electrochromic contrast, coloration efficiency, switching speed, stability and optical memory were carefully investigated. The films vary from white to blue and finally dark brown. The electrochromic contrast is 63.9% at 633 nm. The coloration efficiency of the films is relatively high. The response time is less than 3 s.

  7. Decoration of silica nanowires with gold nanoparticles through ultra-short pulsed laser deposition

    Science.gov (United States)

    Gontad, F.; Caricato, A. P.; Cesaria, M.; Resta, V.; Taurino, A.; Colombelli, A.; Leo, C.; Klini, A.; Manousaki, A.; Convertino, A.; Rella, R.; Martino, M.; Perrone, A.

    2017-10-01

    The ablation of a metal target at laser energy densities in the range of 1-10 TW/cm2 leads to the generation of nanoparticles (NP) of the ablated material. This aspect is of particular interest if the immobilization of NPs on three-dimensional (3D) substrates is necessary as for example in sensing applications. In this work the deposition of Au NP by irradiation of a Au bulk target with a sub-picosecond laser beam (500 fs; 248 nm; 10 Hz) on 2D (silica and Si(100)) and 3D substrates (silica nanowire forests) is reported for different number of laser pulses (500, 1000, 1500, 2000, 2500). A uniform coverage of small Au NPs (with a diameter of few nm) on both kinds of substrates has been obtained using a suitable number of laser pulses. The presence of spherical droplets, with a diameter ranging from tens of nm up to few μm was also detected on the substrate surface and their presence can be explained by the weak electron-phonon coupling of Au. The optical characterization of the samples on 2D and 3D substrates evidenced the surface plasmon resonance peak characteristic of the Au NPs although further improvements of the size-distribution are necessary for future applications in sensing devices.

  8. Room temperature nanojoining of Cu-Ag core-shell nanoparticles and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiaqi; Shin, Seungha, E-mail: sshin@utk.edu [The University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering (United States)

    2017-02-15

    Room temperature (T{sub room}, 300 K) nanojoining of Ag has been widely employed in fabrication of microelectronic applications where the shapes and structures of microelectronic components must be maintained. In this research, the joining processes of pure Ag nanoparticles (NPs), Cu-Ag core-shell NPs, and nanowires (NWs) are studied using molecular dynamics simulations at T{sub room}. The evolution of densification, potential energy, and structural deformation during joining process are analyzed to identify joining mechanisms. Depending on geometry, different joining mechanisms including crystallization-amorphization, reorientation, Shockley partial dislocation are determined. A three-stage joining scenario is observed in both joining process of NPs and NWs. Besides, the Cu core does not participate in all joining processes, however, it enhances the mobility of Ag shell atoms, contributing to a higher densification and bonding strength at T{sub room}, compared with pure Ag nanomaterials. The tensile test shows that the nanojoint bears higher rupture strength than the core-shell NW itself. This study deepens understanding in the underlying joining mechanisms and thus nanojoint with desirable thermal, electrical, and mechanical properties could be potentially achieved.

  9. Room temperature nanojoining of Cu-Ag core-shell nanoparticles and nanowires

    International Nuclear Information System (INIS)

    Wang, Jiaqi; Shin, Seungha

    2017-01-01

    Room temperature (T room , 300 K) nanojoining of Ag has been widely employed in fabrication of microelectronic applications where the shapes and structures of microelectronic components must be maintained. In this research, the joining processes of pure Ag nanoparticles (NPs), Cu-Ag core-shell NPs, and nanowires (NWs) are studied using molecular dynamics simulations at T room . The evolution of densification, potential energy, and structural deformation during joining process are analyzed to identify joining mechanisms. Depending on geometry, different joining mechanisms including crystallization-amorphization, reorientation, Shockley partial dislocation are determined. A three-stage joining scenario is observed in both joining process of NPs and NWs. Besides, the Cu core does not participate in all joining processes, however, it enhances the mobility of Ag shell atoms, contributing to a higher densification and bonding strength at T room , compared with pure Ag nanomaterials. The tensile test shows that the nanojoint bears higher rupture strength than the core-shell NW itself. This study deepens understanding in the underlying joining mechanisms and thus nanojoint with desirable thermal, electrical, and mechanical properties could be potentially achieved.

  10. The antimicrobial effect of silicon nanowires decorated with silver and copper nanoparticles

    International Nuclear Information System (INIS)

    Fellahi, Ouarda; Marcon, Lionel; Coffinier, Yannick; Boukherroub, Rabah; Sarma, Rupak K; Saikia, Ratul; Das, Manash R; Hadjersi, Toufik; Maamache, Mustapha

    2013-01-01

    The paper reports on the preparation and antibacterial activity of silicon nanowire (SiNW) substrates coated with Ag or Cu nanoparticles (NPs) against Escherichia coli (E. coli) bacteria. The substrates are easily prepared using the metal-assisted chemical etching of crystalline silicon in hydrofluoric acid/silver nitrate (HF/AgNO 3 ) aqueous solution. Decoration of the SiNWs with metal NPs is achieved by simple immersion in HF aqueous solutions containing silver or copper salts. The SiNWs coated with Ag NPs are biocompatible with human lung adenocarcinoma epithelial cell line A549 while possessing strong antibacterial properties to E. coli. In contrast, the SiNWs decorated with Cu NPs showed higher cytotoxicity and slightly lower antibacterial activity. Moreover, it was also observed that leakage of sugars and proteins from the cell wall of E. coli in interaction with SiNWs decorated with Ag NPs is higher compared to SiNWs modified with Cu NPs. (paper)

  11. Controlling electrodeposited ultrathin amorphous Fe hydroxides film on V-doped nickel sulfide nanowires as efficient electrocatalyst for water oxidation

    Science.gov (United States)

    Shang, Xiao; Yan, Kai-Li; Lu, Shan-Shan; Dong, Bin; Gao, Wen-Kun; Chi, Jing-Qi; Liu, Zi-Zhang; Chai, Yong-Ming; Liu, Chen-Guang

    2017-09-01

    Developing cost-effective electrocatalysts with both high activity and stability remains challenging for oxygen evolution reaction (OER) in water electrolysis. Herein, based on V-doped nickel sulfide nanowire on nickel foam (NiVS/NF), we further conduct controllable electrodeposition of Fe hydroxides film on NiVS/NF (eFe/NiVS/NF) to further improve OER performance and stability. For comparison, ultrafast chemical deposition of Fe hydroxides on NiVS/NF (uFe/NiVS/NF) is also utilized. V-doping of NiVS/NF may introduce more active sites for OER, and nanowire structure can expose abundant active sites and facilitate mass transport. Both of the two depositions generate amorphous Fe hydroxides film covering on the surface of nanowires and lead to enhanced OER activities. Furthermore, electrodeposition strategy realizes uniform Fe hydroxides film on eFe/NiVS/NF confirmed by superior OER activity of eFe/NiVS/NF than uFe/NiVS/NF with relatively enhanced stability. The OER activity of eFe/NiVS/NF depends on various electrodepositon time, and the optimal time (15 s) is obtained with maximum OER activity. Therefore, the controllable electrodeposition of Fe may provide an efficient and simple strategy to enhance the OER properties of electrocatalysts.

  12. Deposition of Nanostructured Thin Film from Size-Classified Nanoparticles

    Science.gov (United States)

    Camata, Renato P.; Cunningham, Nicholas C.; Seol, Kwang Soo; Okada, Yoshiki; Takeuchi, Kazuo

    2003-01-01

    Materials comprising nanometer-sized grains (approximately 1_50 nm) exhibit properties dramatically different from those of their homogeneous and uniform counterparts. These properties vary with size, shape, and composition of nanoscale grains. Thus, nanoparticles may be used as building blocks to engineer tailor-made artificial materials with desired properties, such as non-linear optical absorption, tunable light emission, charge-storage behavior, selective catalytic activity, and countless other characteristics. This bottom-up engineering approach requires exquisite control over nanoparticle size, shape, and composition. We describe the design and characterization of an aerosol system conceived for the deposition of size classified nanoparticles whose performance is consistent with these strict demands. A nanoparticle aerosol is generated by laser ablation and sorted according to size using a differential mobility analyzer. Nanoparticles within a chosen window of sizes (e.g., (8.0 plus or minus 0.6) nm) are deposited electrostatically on a surface forming a film of the desired material. The system allows the assembly and engineering of thin films using size-classified nanoparticles as building blocks.

  13. A p-silicon nanowire/n-ZnO thin film heterojunction diode prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Hazra, Purnima; Jit, S.

    2014-01-01

    This paper represents the electrical and optical characteristics of a SiNW/ZnO heterojunction diode and subsequent studies on the photodetection properties of the diode in the ultraviolet (UV) wavelength region. In this work, silicon nanowire arrays were prepared on p-type (100)-oriented Si substrate by an electroless metal deposition and etching method with the help of ultrasonication. After that, catalyst-free deposition of zinc oxide (ZnO) nanowires on a silicon nanowire (SiNW) array substrate was done by utilizing a simple and cost-effective thermal evaporation technique without using a buffer layer. The SEM and XRD techniques are used to show the quality of the as-grown ZnO nanowire film. The junction properties of the diode are evaluated by measuring current—voltage and capacitance—voltage characteristics. The diode has a well-defined rectifying behavior with a rectification ratio of 190 at ±2 V, turn-on voltage of 0.5 V, and barrier height is 0.727 eV at room temperature under dark conditions. The photodetection parameters of the diode are investigated in the bias voltage range of ±2 V. The diode shows responsivity of 0.8 A/W at a bias voltage of 2 V under UV illumination (wavelength = 365 nm). The characteristics of the device indicate that it can be used for UV detection applications in nano-optoelectronic and photonic devices. (semiconductor devices)

  14. Preparation and characterization of graphene-based vanadium oxide composite semiconducting films with horizontally aligned nanowire arrays

    International Nuclear Information System (INIS)

    Jung, Hye-Mi; Um, Sukkee

    2016-01-01

    Highly oriented crystalline hybrid thin films primarily consisting of Magnéli-phase VO 2 and conductive graphene nanoplatelets are fabricated by a sol–gel process via dipping pyrolysis. A combination of chemical, microstructural, and electrical analyses reveals that graphene oxide (GO)-templated vanadium oxide (VO x ) nanocomposite films exhibit a vertically stacked multi-lamellar nanostructure consisting of horizontally aligned vanadium oxide nanowire (VNW) arrays along the (hk0) set of planes on a GO template, with an average crystallite size of 41.4 Å and a crystallographic tensile strain of 0.83%. In addition, GO-derived VO x composite semiconducting films, which have an sp 3 /sp 2 bonding ratio of 0.862, display thermally induced electrical switching properties in the temperature range of − 20 °C to 140 °C, with a transition temperature of approximately 65 °C. We ascribe these results to the use of GO sheets, which serve as a morphological growth template as well as an electrochemically tunable platform for enhancing the charge-carrier mobility. Moreover, the experimental studies demonstrate that graphene-based Magnéli-phase VO x composite semiconducting films can be used in advanced thermo-sensitive smart sensing/switching applications because of their outstanding thermo-electrodynamic properties and high surface charge density induced by the planar-type VNWs. - Highlights: • VO x -graphene oxide composite (G/VO x ) films were fabricated by sol–gel process. • The G/VO x films mainly consisted of Magnéli-phase VO 2 and reduced graphene sheets. • The G/VO x films exhibited multi-lamellar textures with planar VO x nanowire arrays. • The G/VO x films showed the thermo-sensitive electrical switching properties. • Effects of GOs on the electrical characteristics of the G/VO x films were discussed.

  15. High-quality CdTe films from nanoparticle precursors

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, D.L.; Pehnt, M.; Urgiles, E. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    In this paper the authors demonstrate that nanoparticulate precursors coupled with spray deposition offers an attractive route into electronic materials with improved smoothness, density, and lower processing temperatures. Employing a metathesis approach, cadmium iodide was reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe thin film formation was achieved by spray depositing the nanoparticle colloids (25-75 {Angstrom} diameter) onto substrates at elevated temperatures (T = 280-440{degrees}C) with no further thermal treatment. These films were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Cubic CdTe phase formation was observed by XRD, with a contaminant oxide phase also detected. XPS analysis showed that CdTe films produced by this one-step method contained no Na or C and substantial O. AFM gave CdTe grain sizes of {approx}0.1-0.3 {mu}m for film sprayed at 400{degrees}C. A layer-by-layer film growth mechanism proposed for the one-step spray deposition of nanoparticle precursors will be discussed.

  16. Highly transparent and thermal-stable silver nanowire conductive film covered with ZnMgO by atomic-layer-deposition

    Science.gov (United States)

    Wang, Lei; Huang, Dongchen; Li, Min; Xu, Hua; Zou, Jianhua; Tao, Hong; Peng, Junbiao; Xu, Miao

    2017-12-01

    Solution-processed silver nanowires (AgNWs) have been considered as a promising material for next generation flexible transparent conductive electrodes. However AgNWs films have several intrinsic drawbacks, such as thermal stability and storage stability. Herein, we demonstrate a laminated ZnO/MgO (ZnMgO, ZMO) as a protective layer on the AgNWs films using atomic layer deposition (ALD). The fabricated films exhibited a low sheet resistance of 16 Ω/sq with high transmittance of 91% at 550 nm, an excellent thermal stability and bending property. The ZMO film grows perpendicularly on the surface of the AgNWs, making a perfect coverage of bulk silver nanowires and junction, which can effectively prompt the electrical transport behavior and enhance stability of the silver nanowires network.

  17. Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

    KAUST Repository

    Gemici, Zekeriyya; Schwachulla, Patrick I.; Williamson, Erik H.; Rubner, Michael F.; Cohen, Robert E.

    2009-01-01

    Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

  18. Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

    KAUST Repository

    Gemici, Zekeriyya

    2009-03-11

    Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

  19. Targeted functionalization of nanoparticle thin films via capillary condensation.

    Science.gov (United States)

    Gemici, Zekeriyya; Schwachulla, Patrick I; Williamson, Erik H; Rubner, Michael F; Cohen, Robert E

    2009-03-01

    Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane).

  20. Synthesis and characterization of rhodium sulfide nanoparticles and thin films

    International Nuclear Information System (INIS)

    Sosibo, Ndabenhle M.; Revaprasadu, Neerish

    2008-01-01

    The synthesis and characterization of a rhodium complex, [Rh(S 2 CNEt 2 ) 2 ] is described. The complex was thermolysed at a high temperature (280 deg. C) in the presence of capping agent, hexadecylamine (HDA) to form Rh 2 S 3 nanoparticles. Rod-shaped Rh 2 S 3 nanoparticles with an average length of 26.7 nm and an average breadth of 7.8 nm were synthesized. The complex was also used as a single molecule precursor for the deposition of Rh 2 S 3 thin films on a glass substrate at 350 deg. C and 450 deg. C using the Aerosol Assisted Chemical Vapour Deposition (AACVD) technique. The resultant thin films showed temperature dependent morphologies and showed (0 2 2), (4 1 1) and (6 1 1) lattice planes characteristic of to the orthorhombic Rh 2 S 3 phase. X-ray diffraction and scanning electron microscopy techniques were used to characterize the films

  1. Nanoparticles inclusions in self assembly thin smectic films

    International Nuclear Information System (INIS)

    Hamdoun, B.; Charara, J.; Zaiour, A.

    2004-01-01

    Full text. Processing of nanocomposites based on nanoparticles inclusion in thin smectic-A liquid crystal was reviewed. Thin smectic-A liquid crystal consists of a stack of regularly spaced membranes that are frequently formed in thin diblock copolymers. Particular attention was given to the scientific concepts that underpin the fabrication of special composite derived copolymer components. The complex interplay between suspension stability and its structural evolution during nanomaterials processing was highlighted. Inclusions, such as nanoparticles, coupled locally to the smectic may deform the membranes over a large length scale. We determined the distortion field due to one inclusion using the Landau-de Gennes description of smectic liquid crystals and by neglecting the interactions between nanoparticles. The equilibrium position of the particle was shown to depend on both the surface tension at the film boundary and the volume fraction of the nanoparticles

  2. Silver nanowire/polymer composite soft conductive film fabricated by large-area compatible coating for flexible pressure sensor array

    Science.gov (United States)

    Chen, Sujie; Li, Siying; Peng, Sai; Huang, Yukun; Zhao, Jiaqing; Tang, Wei; Guo, Xiaojun

    2018-01-01

    Soft conductive films composed of a silver nanowire (AgNW) network, a neutral-pH PEDOT:PSS over-coating layer and a polydimethylsiloxane (PDMS) elastomer substrate are fabricated by large area compatible coating processes. The neutral-pH PEDOT:PSS layer is shown to be able to significantly improve the conductivity, stretchability and air stability of the conductive films. The soft conductive films are patterned using a simple maskless patterning approach to fabricate an 8 × 8 flexible pressure sensor array. It is shown that such soft conductive films can help to improve the sensitivity and reduce the signal crosstalk over the pressure sensor array. Project supported by the Science and Technology Commission of Shanghai Municipality (No. 16JC1400603).

  3. High Rate Micromechanical Behavior of Grafted Polymer Nanoparticle Films

    Science.gov (United States)

    Thomas, Edwin

    We report the ultra high strain rate behavior of films comprised of polymer grafted nanoparticles (NPs) and compare the results to homopolymer films. The films are formed by flow coating a suspension of polystyrene (PS) chains of 230 kg/mol grafted to 16nm diameter SiO2\\ at a graft density of 0.6 chains/nm2 resulting a film with 1 vol % SiO2. Films of 267 kg/mol PS were also flow coated and both films were impacted at velocities 350-700 ms-1 using 3.7 micron SiO2\\ projectiles to achieve increments in kinetic energy (KE) of 1:2:4. The KE of the projectiles before and after penetration was measured to determine the penetration energy. TEM and SEM suggest the projectile initially induces plastic flow due to the adiabatic temperature rise from impact. As the projectile deforms the film, the lower magnitude, biaxial stress state in the peripherial regions causes material microvoid formation and initiation of craze growth in the radial and tangential directions. The anchoring of the grafted polymer chains to the NPs increases the penetration energy relative to the pure homopolymer by 50% and the films capacity to delocalize the impact by 200%. These results suggest that highly grafted NP films may be useful in lightweight protection systems. In collaboration with Omri Fried, Olawale Lawal, Yang Jiao, Victor Hsaio, Thevamaran Ramathasan, Mujin Zhou, Richard Vaia.

  4. Method for producing nanowire-polymer composite electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Qibing; Yu, Zhibin

    2017-11-21

    A method for producing flexible, nanoparticle-polymer composite electrodes is described. Conductive nanoparticles, preferably metal nanowires or nanotubes, are deposited on a smooth surface of a platform to produce a porous conductive layer. A second application of conductive nanoparticles or a mixture of nanoparticles can also be deposited to form a porous conductive layer. The conductive layer is then coated with at least one coating of monomers that is polymerized to form a conductive layer-polymer composite film. Optionally, a protective coating can be applied to the top of the composite film. In one embodiment, the monomer coating includes light transducing particles to reduce the total internal reflection of light through the composite film or pigments that absorb light at one wavelength and re-emit light at a longer wavelength. The resulting composite film has an active side that is smooth with surface height variations of 100 nm or less.

  5. Uniformly sized gold nanoparticles derived from PS-b-P2VP block copolymer templates for the controllable synthesis of Si nanowires.

    Science.gov (United States)

    Lu, Jennifer Q; Yi, Sung Soo

    2006-04-25

    A monolayer of gold-containing surface micelles has been produced by spin-coating solution micelles formed by the self-assembly of the gold-modified polystyrene-b-poly(2-vinylpyridine) block copolymer in toluene. After oxygen plasma removed the block copolymer template, highly ordered and uniformly sized nanoparticles have been generated. Unlike other published methods that require reduction treatments to form gold nanoparticles in the zero-valent state, these as-synthesized nanoparticles are in form of metallic gold. These gold nanoparticles have been demonstrated to be an excellent catalyst system for growing small-diameter silicon nanowires. The uniformly sized gold nanoparticles have promoted the controllable synthesis of silicon nanowires with a narrow diameter distribution. Because of the ability to form a monolayer of surface micelles with a high degree of order, evenly distributed gold nanoparticles have been produced on a surface. As a result, uniformly distributed, high-density silicon nanowires have been generated. The process described herein is fully compatible with existing semiconductor processing techniques and can be readily integrated into device fabrication.

  6. The self-activation and synergy of amorphous Re nanoparticle – Si nanowire composites for the electrocatalytic hydrogen evolution

    International Nuclear Information System (INIS)

    Yang, Lulu; Lu, Shunkai; Wang, Hui; Shao, Qi; Liao, Fan; Shao, Mingwang

    2017-01-01

    Highlights: • Amorphous Re nanoparticle modified Si nanowire nanocomposites were prepared. • An interesting self-activation phenomenon was observed in HER process. • Re/SiNW showed synergy in HER process. • The optimal mass ratio of Re: Si was determined to be 31.1: 68.9. - Abstract: Amorphous rhenium nanoparticles modified silicon nanowires were prepared via reducing Re ion by Si−H bonds, which were employed to electrocatalysize the hydrogen evolution reaction because amorphous structure may have excellent catalytic activity. It is interesting that an obvious self-activation for Re/Si catalysts was observed with the current density enhanced by 2.2 times its previous value at 400 mV after a 3,000 s of continuous cyclic voltammetry scanning, and the catalytic performance remained steady thereafter. The optimal electrocatalytic performance was found with the Re: Si mass ratio of 31.1: 68.9, resulting in a Tafel slope of 81 mV·dec −1 and overpotential of 100 mV at current density of 10 mA·cm −2 .

  7. Ultraflexible Transparent Film Heater Made of Ag Nanowire/PVA Composite for Rapid-Response Thermotherapy Pads.

    Science.gov (United States)

    Lan, Wei; Chen, Youxin; Yang, Zhiwei; Han, Weihua; Zhou, Jinyuan; Zhang, Yue; Wang, Junya; Tang, Guomei; Wei, Yupeng; Dou, Wei; Su, Qing; Xie, Erqing

    2017-02-22

    Ultraflexible transparent film heaters have been fabricated by embedding conductive silver (Ag) nanowires into a thin poly(vinyl alcohol) film (AgNW/PVA). A cold-pressing method was used to rationally adjust the sheet resistance of the composite films and thus the heating powers of the AgNW/PVA film heaters at certain biases. The film heaters have a favorable optical transmittance (93.1% at 26 Ω/sq) and an outstanding mechanical flexibility (no visible change in sheet resistance after 10 000 bending cycles and at a radius of curvature ≤1 mm). The film heaters have an environmental endurance, and there is no significant performance degradation after being kept at high temperature (80 °C) and high humidity (45 °C, 80% humidity) for half a year. The efficient Joule heating can increase the temperature of the film heaters (20 Ω/sq) to 74 °C in ∼20 s at a bias of 5 V. The fast-heating characteristics at low voltages (a few volts) associated with its transparent and flexibility properties make the poly(dimethylsiloxane)/AgNW/PVA composite film a potential candidate in medical thermotherapy pads.

  8. Ultradense, Deep Subwavelength Nanowire Array Photovoltaics As Engineered Optical Thin Films

    KAUST Repository

    Tham, Douglas; Heath, James R.

    2010-01-01

    A photovoltaic device comprised of an array of 20 nm wide, 32 nm pitch array of silicon nanowires is modeled as an optical material. The nanowire array (NWA) has characteristic device features that are deep in the subwavelength regime for light

  9. Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

    Science.gov (United States)

    Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

    2012-02-01

    Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate.

  10. Structure and frictional properties of Langmuir-Blodgett films of Cu nanoparticles modified by dialkyldithiophosphate

    International Nuclear Information System (INIS)

    Xu Jun; Dai Shuxi; Cheng Gang; Jiang Xiaohong; Tao Xiaojun; Zhang Pingyu; Du Zuliang

    2006-01-01

    Langmuir-Blodgett (LB) films of dialkyldithiophosphate (DDP) modified Cu nanoparticles were prepared. The structure, microfrictional behaviors and adhesion of the LB films were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic/friction force microscopy (AFM/FFM). Our results showed that the modified Cu nanoparticles have a typical core-shell structure and fine film-forming ability. The images of AFM/FFM showed that LB films of modified Cu nanoparticles were composed of many nanoparticles arranged closely and orderly and the nanoparticles had favorable behaviors of lower friction. The friction loop of the films indicated that the friction force was affected prominently by the surface slope of the Cu nanoparticles and the microfrictional behaviors showed obvious 'ratchet effect'. The adhesion experiment showed that the modified Cu nanoparticle had a very small adhesive force

  11. X-ray Reciprocal Space Mapping of Graded Al x Ga1 - x N Films and Nanowires.

    Science.gov (United States)

    Stanchu, Hryhorii V; Kuchuk, Andrian V; Kladko, Vasyl P; Ware, Morgan E; Mazur, Yuriy I; Zytkiewicz, Zbigniew R; Belyaev, Alexander E; Salamo, Gregory J

    2016-12-01

    The depth distribution of strain and composition in graded Al x Ga1 - x N films and nanowires (NWs) are studied theoretically using the kinematical theory of X-ray diffraction. By calculating [Formula: see text] reciprocal space maps (RSMs), we demonstrate significant differences in the intensity distributions from graded Al x Ga1 - x N films and NWs. We attribute these differences to relaxation of the substrate-induced strain on the NWs free side walls. Finally, we demonstrate that the developed X-ray reciprocal space map model allows for reliable depth profiles of strain and Al composition determination in both Al x Ga1 - x N films and NWs.

  12. Mn doped GaN thin films and nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Šofer, Z.; Sedmidubský, D.; Huber, Š.; Hejtmánek, Jiří; Macková, Anna; Fiala, R.

    2012-01-01

    Roč. 9, 8-9 (2012), s. 809-824 ISSN 1475-7435 R&D Projects: GA ČR GA104/09/0621 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10480505 Keywords : GaN nanoparticles * GaN thin films * manganese * transition metals * MOVPE * ion implantations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.087, year: 2012

  13. Controlling thin film structure for the dewetting of catalyst nanoparticle arrays for subsequent carbon nanofiber growth

    International Nuclear Information System (INIS)

    Randolph, S J; Fowlkes, J D; Melechko, A V; Klein, K L; III, H M Meyer; Simpson, M L; Rack, P D

    2007-01-01

    Vertically aligned carbon nanofiber (CNF) growth is a catalytic chemical vapor deposition process in which structure and functionality is controlled by the plasma conditions and the properties of the catalyst nanoparticles that template the fiber growth. We have found that the resultant catalyst nanoparticle network that forms by the dewetting of a continuous catalyst thin film is dependent on the initial properties of the thin film. Here we report the ability to tailor the crystallographic texture and composition of the nickel catalyst film and subsequently the nanoparticle template by varying the rf magnetron sputter deposition conditions. After sputtering the Ni catalyst thin films, the films are heated and exposed to an ammonia dc plasma, to chemically reduce the native oxide on the films and induce dewetting of the film to form nanoparticles. Subsequent nanoparticle treatment in an acetylene plasma at high substrate temperature results in CNF growth. Evidence is presented that the texture and composition of the nickel thin film has a significant impact on the structure and composition of the formed nanoparticle, as well as the resultant CNF morphology. Nickel films with a preferred (111) or (100) texture were produced and conditions favoring interfacial silicidation reactions were identified and investigated. Both compositional and structural analysis of the films and nanoparticles indicate that the properties of the as-deposited Ni catalyst film influences the subsequent nanoparticle formation and ultimately the catalytic growth of the carbon nanofibers

  14. High-transparency and low-resistivity poly (methylmethacrylate) films containing silver nanowires and graphene-oxide nanoplatelets

    International Nuclear Information System (INIS)

    Bang, Yo Han; Choo, Dong Chul; Kim, Tae Whan

    2016-01-01

    Highlights: • PMMA films containing both Ag-NWs and GONPs were formed by using a transfer method. • Scanning electron microscopy images showed that the Ag-NWs on the PMMA film were partially covered with the GONPs. • Transmittance and the sheet resistance of the PMMA films were approximately 90% at 550 nm and 24 Ω/sq, respectively. • Uniformity of the sheet resistance was significantly improved due to the GONP treatment. • XPS spectra showed that the enhancement in the sheet resistance originated from the quaternary nitrogen in the GONPs. - Abstract: Nanocomposite films containing silver nanowires (Ag NWs) and graphene-oxide nanoplatelets (GONPs) were formed on glass, and the nanocomposite films were then transferred to poly(methylmethacrylate) (PMMA) films. Scanning electron microscopy images showed that Ag NWs with a length of 20 μm and a width of 80 nm, together with GONPs with a size of 15 μm, had been formed on the PMMA film and that the Ag NWs on the PMMA film were partially covered with the GONPs. While the transmittance of the PMMA film with the Ag NWs and the GONPs was almost the same as that of the PMMA film with the Ag NWs alone, the corresponding sheet resistance was decreased due to the generation of quaternary nitrogen in the GONPs, which the results of X-ray photoelectron spectroscopy and Raman spectroscopy confirmed. The transmittance and the sheet resistance of the PMMA film containing Ag NWs and GONPs were approximately 90% at 550 nm and 24 Ohm/sq, respectively.

  15. Formulation and Characterization of Acetaminophen Nanoparticles in Orally Disintegrating Films

    Science.gov (United States)

    AI-Nemrawi, Nusaiba K.

    The purpose of this study is to prepare acetaminophen loaded nanoparticles to be cast directly, while still in the emulsion form, into Orally Disintegrating Films (ODF). By casting the nanoparticles in the films, we expected to keep the particles in a stable form where the nanoparticles would be away from each other to prevent their aggregation. Once the films are applied on the buccal mucosa, they are supposed to dissolve within seconds, releasing the nanoparticles. Then the nanoparticles could be directly absorbed through the mucosa to the blood stream and deliver acetaminophen there. The oral cavity mucosa is one of the most attractive sites for systemic drug delivery due to its high permeability and blood supply. Furthermore, it is robust and shows short recovery times after stress or damage, and the drug bypasses first pass effect and avoids presystemic elimination in the GI tract. Nanoencapsulation increases drug efficacy, specificity, tolerability and therapeutic index. These Nanocapsules have several advantages in the protection of premature degradation and interaction with the biological environment, enhancement of absorption into a selected tissue, bioavailability, retention time and improvement of intracellular penetration. The most important characteristics of nanoparticles are their size, encapsulation efficiency (EE), zeta potential (surface charge), and the drug release profiles. Unfortunately, nanoparticles tend to precipitate or aggregate into larger particles within a short time after preparation or during storage. Some solutions for this problem were mentioned in literature including lyophilization and spray drying. These methods are usually expensive and give partial solutions that might have secondary problems; such as low re-dispersion efficacy of the lyophilized NPs. Furthermore, most of the formulations of NPs are invasive or topical. Few formulas are available to be given orally. Fast disintegrating films (ODFs) are rapidly gaining interest

  16. Superconducting nanowire single photon detectors fabricated from an amorphous Mo0.75Ge0.25 thin film

    International Nuclear Information System (INIS)

    Verma, V. B.; Lita, A. E.; Vissers, M. R.; Marsili, F.; Pappas, D. P.; Mirin, R. P.; Nam, S. W.

    2014-01-01

    We present the characteristics of superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous Mo 0.75 Ge 0.25 thin-films. Fabricated devices show a saturation of the internal detection efficiency at temperatures below 1 K, with system dark count rates below 500 cps. Operation in a closed-cycle cryocooler at 2.5 K is possible with system detection efficiencies exceeding 20% for SNSPDs which have not been optimized for high detection efficiency. Jitter is observed to vary between 69 ps at 250 mK and 187 ps at 2.5 K using room temperature amplifiers.

  17. Plasma-activated core-shell gold nanoparticle films with enhanced catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Llorca, Jordi, E-mail: jordi.llorca@upc.edu; Casanovas, Albert; Dominguez, Montserrat; Casanova, Ignasi [Universitat Politecnica de Catalunya, Institut de Tecniques Energetiques (Spain); Angurell, Inmaculada; Seco, Miquel; Rossell, Oriol [Universitat de Barcelona, Departament de Quimica Inorganica (Spain)

    2008-03-15

    Catalytically active gold nanoparticle films have been prepared from core-shell nanoparticles by plasma-activation and characterized by high-resolution transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Methane can be selectively oxidized into formic acid with an O{sub 2}-H{sub 2} mixture in a catalytic wall reactor functionalized with plasma-activated gold nanoparticle films containing well-defined Au particles of about 3.5 nm in diameter. No catalytic activity was recorded over gold nanoparticle films prepared by thermal decomposition of core-shell nanoparticles due to particle agglomeration.

  18. Plasma-activated core-shell gold nanoparticle films with enhanced catalytic properties

    International Nuclear Information System (INIS)

    Llorca, Jordi; Casanovas, Albert; Dominguez, Montserrat; Casanova, Ignasi; Angurell, Inmaculada; Seco, Miquel; Rossell, Oriol

    2008-01-01

    Catalytically active gold nanoparticle films have been prepared from core-shell nanoparticles by plasma-activation and characterized by high-resolution transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Methane can be selectively oxidized into formic acid with an O 2 -H 2 mixture in a catalytic wall reactor functionalized with plasma-activated gold nanoparticle films containing well-defined Au particles of about 3.5 nm in diameter. No catalytic activity was recorded over gold nanoparticle films prepared by thermal decomposition of core-shell nanoparticles due to particle agglomeration

  19. Synthesis, characterization and formaldehyde gas sensitivity of La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanoparticles assembled nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Yao Pengjun [School of Electronic Science and Technology, Dalian University of Technology, Dalian 116023 (China); School of Educational Technology, Shenyang Normal University, Shenyang 110034 (China); Wang Jing, E-mail: wangjing@dlut.edu.cn [School of Electronic Science and Technology, Dalian University of Technology, Dalian 116023 (China); Du Haiying [School of Electronic Science and Technology, Dalian University of Technology, Dalian 116023 (China); Department of Electromechanical Engineering and Information, Dalian Nationalities University, Dalian 116600 (China); Qi Jinqing [School of Electronic Science and Technology, Dalian University of Technology, Dalian 116023 (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer High aspect ratio La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanoparticles assembled nanowires were synthesized by a CTAB assisted hydrothermal method. Black-Right-Pointing-Pointer Formaldehyde with low concentration (0.1-100 ppm) was used for gas sensing study. Black-Right-Pointing-Pointer The growth mechanism of La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanowires was reported. - Abstract: La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanoparticles assembled nanowires were synthesized by a hydrothermal method assisted with cetyltrimethylammonium bromide (CTAB). The hydrothermal temperature was 180 Degree-Sign C and the annealed temperature was 700 Degree-Sign C. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, composition and structural properties of the materials. The results showed that the La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanoparticles assembled nanowires had a high aspect ratio (the largest aspect ratio >100); the size of the nanoparticles was about 20 nm and the diameter of the nanowires was about 100-150 nm. The growth mechanism of La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanowires was discussed. Gas sensors were fabricated by using La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanowires. Formaldehyde gas sensing properties were carried out in the concentration range of 0.1-100 ppm at the optimum operating temperature of 280 Degree-Sign C. The response and recovery times to 20 ppm formaldehyde of the sensor were 110 s and 50 s, respectively. The gas sensing mechanism of La{sub 0.7}Sr{sub 0.3}FeO{sub 3} nanowires was investigated.

  20. Enhanced photoelectric performance in self-powered UV detectors based on ZnO nanowires with plasmonic Au nanoparticles scattered electrolyte

    Science.gov (United States)

    Zeng, Yiyu; Ye, Zhizhen; Lu, Bin; Dai, Wei; Pan, Xinhua

    2016-04-01

    Vertically aligned ZnO nanowires (NWs) were grown on a fluorine-doped tin-oxide-coated glass substrate by a hydrothermal method. Au nanoparticles were well dispersed in the mixed solution of ethanol and deionized water. A simple self-powered ultraviolet detector based on solid-liquid heterojunction was fabricated, utilizing ZnO NWs as active photoanode and such prepared mixed solution as electrolyte. The introduction of Au nanoparticles results in considerable improvements in the responsivity and sensitivity of the device compared with the one using deionized water as electrolyte, which is attributed to the enhanced light harvesting by Au nanoparticles.

  1. Mercury adsorption to gold nanoparticle and thin film surfaces

    Science.gov (United States)

    Morris, Todd Ashley

    Mercury adsorption to gold nanoparticle and thin film surfaces was monitored by spectroscopic techniques. Adsorption of elemental mercury to colloidal gold nanoparticles causes a color change from wine-red to orange that was quantified by UV-Vis absorption spectroscopy. The wavelength of the surface plasmon mode of 5, 12, and 31 nm gold particles blue-shifts 17, 14, and 7.5 nm, respectively, after a saturation exposure of mercury vapor. Colorimetric detection of inorganic mercury was demonstrated by employing 2.5 nm gold nanoparticles. The addition of low microgram quantities of Hg 2+ to these nanoparticles induces a color change from yellow to peach or blue. It is postulated that Hg2+ is reduced to elemental mercury by SCN- before and/or during adsorption to the nanoparticle surface. It has been demonstrated that surface plasmon resonance spectroscopy (SPRS) is sensitive to mercury adsorption to gold and silver surfaces. By monitoring the maximum change in reflectivity as a function of amount of mercury adsorbed to the surface, 50 nm Ag films were shown to be 2--3 times more sensitive than 50 nm Au films and bimetallic 15 nm Au/35 nm Ag films. In addition, a surface coverage of ˜40 ng Hg/cm2 on the gold surface results in a 0.03° decrease in the SPR angle of minimum reflectivity. SPRS was employed to follow Hg exposure to self-assembled monolayers (SAMs) on Au. The data indicate that the hydrophilic or hydrophobic character of the SAM has a significant effect on the efficiency of Hg penetration. Water adsorbed to carboxylic acid end group of the hydrophilic SAMs is believed to slow the penetration of Hg compared to methyl terminated SAMs. Finally, two protocols were followed to remove mercury from gold films: immersion in concentrated nitric acid and thermal annealing up to 200°C. The latter protocol is preferred because it removes all of the adsorbed mercury from the gold surface and does not affect the morphology of the gold surface.

  2. Preparation and characterization of flexible asymmetric supercapacitors based on transition-metal-oxide nanowire/single-walled carbon nanotube hybrid thin-film electrodes.

    Science.gov (United States)

    Chen, Po-Chiang; Shen, Guozhen; Shi, Yi; Chen, Haitian; Zhou, Chongwu

    2010-08-24

    In the work described in this paper, we have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on transition-metal-oxide nanowire/single-walled carbon nanotube (SWNT) hybrid thin-film electrodes. These hybrid nanostructured films, with advantages of mechanical flexibility, uniform layered structures, and mesoporous surface morphology, were produced by using a filtration method. Here, manganese dioxide nanowire/SWNT hybrid films worked as the positive electrode, and indium oxide nanowire/SWNT hybrid films served as the negative electrode in a designed ASC. In our design, charges can be stored not only via electrochemical double-layer capacitance from SWNT films but also through a reversible faradic process from transition-metal-oxide nanowires. In addition, to obtain stable electrochemical behavior during charging/discharging cycles in a 2 V potential window, the mass balance between two electrodes has been optimized. Our optimized hybrid nanostructured ASCs exhibited a superior device performance with specific capacitance of 184 F/g, energy density of 25.5 Wh/kg, and columbic efficiency of approximately 90%. In addition, our ASCs exhibited a power density of 50.3 kW/kg, which is 10-fold higher than obtained in early reported ASC work. The high-performance hybrid nanostructured ASCs can find applications in conformal electrics, portable electronics, and electrical vehicles.

  3. All-solid-state thin film battery based on well-aligned slanted LiCoO{sub 2} nanowires fabricated by glancing angle deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Miyoung [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Seunghwan [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Daehee [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Joosun, E-mail: joosun@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Moon, Jooho, E-mail: jmoon@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2017-08-01

    Graphical abstract: We successfully fabricated well-aligned slanted LiCoO{sub 2} nanowires as a one-dimensional nanostructured cathode by glancing angle deposition to enhance the electrochemical performance of all-solid-state thin film batteries. - Highlights: • Well-aligned slanted LiCoO{sub 2} nanowires are fabricated by glancing angle deposition. • One-dimensional nanostructured LiCoO{sub 2} cathode enlarges the contact area. • All-solid-state thin film battery exhibits enhances rate capability and cycling stability. - Abstract: We fabricated all-solid-state thin film batteries based on well-aligned slanted LiCoO{sub 2} nanowires by glancing angle deposition, as a facile template-free method in order to increase the electrochemically active site, i.e., the contact area between the solid electrolyte and the electrode. A highly porous thin film composed of well-separated slanted LiCoO{sub 2} nanowires not only facilitates the penetration of solid electrolyte phase into the cathode, but also alleviates the thermally and mechanically induced stresses during post-annealing and electrochemical cycling. The all-solid-state thin film battery based on the well-aligned slanted LiCoO{sub 2} nanowires, whose contact area between electrolyte and electrode was three times as high as that of a dense thin film, could provide additional migration pathways for lithium ion diffusion due to the enlarged reaction sites. This resulted in enhanced electrochemical kinetics, thereby leading to better rate capability and long-term cyclic stability as compared to the dense LiCoO{sub 2} thin film.

  4. Phase-transfer and film formation of silver nanoparticles.

    Science.gov (United States)

    Sarkar, Anjana; Chadha, Ridhima; Biswas, Nandita; Mukherjee, Tulsi; Kapoor, Sudhir

    2009-04-01

    In this article, a simple method for either transfer of silver nanoparticles from formamide to chloroform or to form a film at their interface is demonstrated. The transfer of the particles is a two-step size-dependent process. The size distribution of the colloidal hydrophobic silver particles in chloroform was almost the same as that before its transfer. Particles can be isolated by evaporation of chloroform. During evaporation, the hydrophobic particles become hydrophilic (charged) due to the formation of bilayer of CTAB over their surface. The isolated particles can be re-dispersed easily in polar solvents such as water and methanol. Nanocrystalline film of Ag is also prepared at the formamide-chloroform interface using suitable stabilizers in two immiscible layers. The nanocrystals have been characterized by various microscopic and spectroscopic techniques. The free standing film could be easily transferred on solid support.

  5. Mechanism of large optical nonlinearity in gold nanoparticle films.

    Science.gov (United States)

    Mirza, I; McCloskey, D; Blau, W J; Lunney, J G

    2018-04-01

    The Z-scan technique, using femtosecond (fs) laser pulses at 1480 nm laser pulses, was used to measure the nonlinear optical properties of gold (Au) nanoparticle (NP) films made by both nanosecond (ns) and fs pulsed laser deposition (PLD) in vacuum. At irradiance levels of 1×10 12   Wm -2 , the ns-PLD films displayed induced absorption with β=4×10 -5   mW -1 , and a negative lensing effect with n 2 =-4.7×10 -11   m 2  W -1 with somewhat smaller values for the fs-PLD films. These values of n 2 imply an unphysically large change in the real part of the refractive index, demonstrating the need to take account of nonlinear changes of the Fresnel coefficients and multiple beam interference in Z-scan measurements on nanoscale films. Following this approach, the Z-scan observations were analyzed to determine the effective complex refractive index of the NP film at high irradiance. It appears that at high irradiance the NP film behaves as a metal, while at low irradiance it behaves as a low-loss dielectric. Thus, it is conjectured that, for high irradiance near the waist of the Z-scan laser beam, laser driven electron tunneling between NPs gives rise to metal-like optical behavior.

  6. Probing the phase diagram of cuprates with YBa2Cu3O7 -δ thin films and nanowires

    Science.gov (United States)

    Arpaia, Riccardo; Andersson, Eric; Trabaldo, Edoardo; Bauch, Thilo; Lombardi, Floriana

    2018-02-01

    We have grown and characterized 30-nm-thick YBa2Cu3O7 -δ (YBCO) films, deposited by pulsed laser deposition on both MgO (110) and SrTiO3 (001) substrates, which induce opposite strain to the superconducting layer. By carefully tuning the in situ post-annealing oxygen pressure, we achieved, in a reproducible way, films at different oxygen doping, spanning from the slightly overdoped down to the strongly underdoped region of the phase diagram. The transport properties of the films, investigated through resistance versus temperature measurements, are in perfect qualitative agreement with single crystals. Starting from these films, we have also successfully fabricated nanowires with widths down to 65 nm, at different oxygen doping. The nanostructures exhibit characteristic temperatures (as the critical temperature Tc and the pseudogap temperature T*) similar to those of the as-grown films and carry critical current densities Jc close to the critical depairing value, limited by vortex entry. This implies that the superconducting and the normal state properties of underdoped YBCO are preserved in our films, and they can be studied as a function of the dimensionality of the system, down to the nanoscale.

  7. 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.

  8. Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

    Directory of Open Access Journals (Sweden)

    Suvarna R. Bathe

    2014-01-01

    Full Text Available Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101 plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600 nm fiber diameter and nanocrystalline having size 40 nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3.

  9. Improved polymer thin-film wetting behavior through nanoparticle segregation to interfaces

    International Nuclear Information System (INIS)

    Krishnan, R S; Mackay, M E; Duxbury, P M; Hawker, C J; Asokan, Suba; Wong, Michael S; Goyette, Rick; Thiyagarajan, P

    2007-01-01

    We report a systematic study of improved wetting behavior for thin polymer films containing nanoparticles, as a function of nanoparticle size and concentration, the energy of the substrate and the dielectric properties of the nanoparticles. An enthalpy matched system consisting of polystyrene nanoparticles in linear polystyrene is used to show that nanoparticles are uniformly distributed in the film after spin coating and drying. However, on annealing the film above its bulk glass transition temperature these nanoparticles segregate strongly to the solid substrate. We find that for a wide range of film thicknesses and nanoparticle sizes, a substrate coverage of nanoparticles of approximately a monolayer is required for dewetting inhibition. Cadmium selenide quantum dots also inhibit dewetting of polystyrene thin films, again when a monolayer is present. Moreover, TEM microscopy images indicate that CdSe quantum dots segregate primarily to the air interface. Theoretical interpretation of these phenomena suggests that gain of linear chain configurational entropy promotes segregation of nanoparticles to the solid substrate, as occurs for polystyrene nanoparticles; however, for CdSe nanoparticles this is offset by surface energy or enthalpic terms which promote segregation of the nanoparticles to the air interface

  10. Controlled self-decoration of Mo6SyIz (8.2 ≤ y + z ≤ 10) nanowires and their transformation to MoS2 nanotubes with gold nanoparticles

    International Nuclear Information System (INIS)

    Kovič, Andrej; Vengust, Damjan; Vilfan, Mojca; Mrzel, Aleš

    2013-01-01

    Nanowires and nanotubes decorated with gold nanoparticles are known for their excellent sensing and catalytic properties. However, the decoration of transition–metal dichalcogenide nanotubes can be very complex. Here we report on a simple procedure that enables efficient production and purification of thin bundles of Mo 6 S y I z (8.2 ≤ y + z ≤ 10) nanowires decorated with gold nanoparticles and their transformation to gold-decorated MoS 2 nanotubes. We isolated several hundred milligrams of nanowire bundles that were several microns long with average diameters of around 40 nm, and formed a stable dispersion in water without added surfactants. Gold nanoparticles were directly deposited on the nanowire bundles either in a solution or on a substrate at room temperature in a single-step reaction without any additional reducing reagents. The number of gold nanoparticles on a nanowire bundle is controlled by changing the concentration of chloroauric acid HAuCl 4 ·3H 2 O in the solution. Since the nanowires can serve as precursor crystals for fabrication of nanotubes, we were able to transform gold-decorated nanowires and produce gold-decorated MoS 2 nanotubes

  11. Growth Mechanism of Nanowires: Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Hopkins, R. H.; Su, Ching Hua; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    In the past two decades there has been a large rise in the investment and expectations for nanotechnology use. Almost every area of research has projected improvements in sensors, or even a promise for the emergence of some novel device technologies. For these applications major focuses of research are in the areas of nanoparticles and graphene. Although there are some near term applications with nanowires in photodetectors and other low light detectors, there are few papers on the growth mechanism and fabrication of nanowire-based devices. Semiconductor nanowires exhibit very favorable and promising optical properties, including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here an overview of the mechanism of nanowire growth from the melt, and some preliminary results for the thallium arsenic selenide material system. Thallium arsenic selenide (TAS) is a multifunctional material combining excellent acousto-optical, nonlinear and radiation detection properties. We observed that small units of (TAS) nanocubes arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. In some cases very long wires (less than mm) are formed. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places.

  12. Enhanced performance of GaN-based light-emitting diodes with graphene/Ag nanowires hybrid films

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2013-04-01

    Full Text Available Incorporating Ag nanowires with graphene resulted in improved electrical conductivity and enhanced contact properties between graphene and p-GaN. The graphene/AgNWs hybrid films exhibited high transmittance and lower sheet resistance compared to bare graphene. The specific contact resistance between graphene and p-GaN reduced nearly an order of magnitude with the introduction of AgNWs. As a result, light emitting diodes based on the hybrid films showed 44% lower forward voltage and 2-fold higher light output power. The enhanced performance was attributed to the bridging by AgNWs of cracks, grain boundaries in graphene and the reduction of Schottky barrier height at graphene/ p-GaN interface.

  13. Hydrothermal Growth and Application of ZnO Nanowire Films with ZnO and TiO2Buffer Layers in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jiang Chunhua

    2009-01-01

    Full Text Available Abstract This paper reports the effects of the seed layers prepared by spin-coating and dip-coating methods on the morphology and density of ZnO nanowire arrays, thus on the performance of ZnO nanowire-based dye-sensitized solar cells (DSSCs. The nanowire films with the thick ZnO buffer layer (~0.8–1 μm thick can improve the open circuit voltage of the DSSCs through suppressing carrier recombination, however, and cause the decrease of dye loading absorbed on ZnO nanowires. In order to further investigate the effect of TiO2buffer layer on the performance of ZnO nanowire-based DSSCs, compared with the ZnO nanowire-based DSSCs without a compact TiO2buffer layer, the photovoltaic conversion efficiency and open circuit voltage of the ZnO DSSCs with the compact TiO2layer (~50 nm thick were improved by 3.9–12.5 and 2.4–41.7%, respectively. This can be attributed to the introduction of the compact TiO2layer prepared by sputtering method, which effectively suppressed carrier recombination occurring across both the film–electrolyte interface and the substrate–electrolyte interface.

  14. Synthesis and characterization of rhodium sulfide nanoparticles and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sosibo, Ndabenhle M. [Department of Chemistry, University of Zululand, Private Bag X1001, KwaDlangezwa 3886 (South Africa); Revaprasadu, Neerish [Department of Chemistry, University of Zululand, Private Bag X1001, KwaDlangezwa 3886 (South Africa)], E-mail: nrevapra@pan.uzulula.za

    2008-05-15

    The synthesis and characterization of a rhodium complex, [Rh(S{sub 2}CNEt{sub 2}){sub 2}] is described. The complex was thermolysed at a high temperature (280 deg. C) in the presence of capping agent, hexadecylamine (HDA) to form Rh{sub 2}S{sub 3} nanoparticles. Rod-shaped Rh{sub 2}S{sub 3} nanoparticles with an average length of 26.7 nm and an average breadth of 7.8 nm were synthesized. The complex was also used as a single molecule precursor for the deposition of Rh{sub 2}S{sub 3} thin films on a glass substrate at 350 deg. C and 450 deg. C using the Aerosol Assisted Chemical Vapour Deposition (AACVD) technique. The resultant thin films showed temperature dependent morphologies and showed (0 2 2), (4 1 1) and (6 1 1) lattice planes characteristic of to the orthorhombic Rh{sub 2}S{sub 3} phase. X-ray diffraction and scanning electron microscopy techniques were used to characterize the films.

  15. Strong saturable absorption of black titanium oxide nanoparticle films

    Science.gov (United States)

    Zhang, Rong-Fang; Guo, Deng-Zhu; Zhang, Geng-Min

    2017-12-01

    Nonlinear optical materials with strong saturable absorption (SA) properties play an essential role in passive mode-locking generation of ultrafast lasers. Here we report black TiO2-x nanoparticles are promising candidate for such an application. Black TiO2-x nanoparticles are synthesized by using cathodic plasma electrolysis, and nanoparticle films are deposited on optical glass plates via natural sedimentation and post annealing. Characterization of the samples with TEM, SEM, XRD and XPS reveal that nanoparticles have diameters of 8-70 nm, and are in polycrystalline structure and co-existence of anatase, rutile and abundant oxygen-deficient phases. Optical transmittance and reflectance measurements with a UV/VIS/NIR spectrophotometer evidence an excellent wide-spectral optical absorption property. The nonlinear optical properties of the samples were measured by using open-aperture Z-scan technique with picosecond 532-nm laser, and verified by direct transmission measurements using nanosecond 1064-nm laser. Strong SA behavior was detected, and the nonlinear absorption coefficient is as high as β = - 4.9 × 10-8 m/W, at least two orders larger than most previous reports on ordinary TiO2. The strong SA behaviors are ascribed to the existence of plenty surface states and defect states within bandgap, and the relaxation rates of electrons from upper energy levels to lower ones are much slower than excitation rates.

  16. Growth and characterization of ceria thin films and Ce-doped {gamma}-Al{sub 2}O{sub 3} nanowires using sol-gel techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gravani, S; Polychronopoulou, K; Doumanidis, C C; Rebholz, C [Mechanical and Manufacturing Engineering Department, Engineering School, University of Cyprus, 1678, Nicosia (Cyprus); Stolojan, V; Hinder, S J; Baker, M A [Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); Cui, Q; Gu, Z [Department of Chemical Engineering and CHN/NCOE Nanomanufacturing Center, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Gibson, P N, E-mail: M.Baker@surrey.ac.uk [Institute for Health and Consumer Protection, Joint Research Centre of the European Commission, 21027 Ispra (Italy)

    2010-11-19

    {gamma}-Al{sub 2}O{sub 3} is a well known catalyst support. The addition of Ce to {gamma}-Al{sub 2}O{sub 3} is known to beneficially retard the phase transformation of {gamma}-Al{sub 2}O{sub 3} to {alpha}-Al{sub 2}O{sub 3} and stabilize the {gamma}-pore structure. In this work, Ce-doped {gamma}-Al{sub 2}O{sub 3} nanowires have been prepared by a novel method employing an anodic aluminium oxide (AAO) template in a 0.01 M cerium nitrate solution, assisted by urea hydrolysis. Calcination at 500 deg. C for 6 h resulted in the crystallization of the Ce-doped AlOOH gel to form Ce-doped {gamma}-Al{sub 2}O{sub 3} nanowires. Ce{sup 3+} ions within the nanowires were present at a concentration of < 1 at.%. On the template surface, a nanocrystalline CeO{sub 2} thin film was deposited with a cubic fluorite structure and a crystallite size of 6-7 nm. Characterization of the nanowires and thin films was performed using scanning electron microscopy, transmission electron microscopy, electron energy loss spectroscopy, x-ray photoelectron spectroscopy and x-ray diffraction. The nanowire formation mechanism and urea hydrolysis kinetics are discussed in terms of the pH evolution during the reaction. The Ce-doped {gamma}-Al{sub 2}O{sub 3} nanowires are likely to find useful applications in catalysis and this novel method can be exploited further for doping alumina nanowires with other rare earth elements.

  17. Thermal dewetting behavior of polystyrene composite thin films with organic-modified inorganic nanoparticles.

    Science.gov (United States)

    Kubo, Masaki; Takahashi, Yosuke; Fujii, Takeshi; Liu, Yang; Sugioka, Ken-ichi; Tsukada, Takao; Minami, Kimitaka; Adschiri, Tadafumi

    2014-07-29

    The thermal dewetting of polystyrene composite thin films with oleic acid-modified CeO2 nanoparticles prepared by the supercritical hydrothermal synthesis method was investigated, varying the nanoparticle concentration (0-30 wt %), film thickness (approximately 50 and 100 nm), and surface energy of silanized silicon substrates on which the composite films were coated. The dewetting behavior of the composite thin films during thermal annealing was observed by an optical microscope. The presence of nanoparticles in the films affected the morphology of dewetting holes, and moreover suppressed the dewetting itself when the concentration was relatively high. It was revealed that there was a critical value of the surface energy of the substrate at which the dewetting occurred. In addition, the spatial distributions of nanoparticles in the composite thin films before thermal annealing were investigated using AFM and TEM. As a result, we found that most of nanoparticles segregated to the surface of the film, and that such distributions of nanoparticles contribute to the stabilization of the films, by calculating the interfacial potential of the films with nanoparticles.

  18. Plasmonic nanoparticle films for solar cell applications fabricated by size-selective aerosol deposition

    NARCIS (Netherlands)

    Pfeiffer, T.V.; Ortiz Gonzalez, J.; Santbergen, R.; Tan, H.; Schmidt-Ott, A.; Zeman, M.; Smets, A.H.M.

    2014-01-01

    A soft deposition method for incorporating surface plasmon resonant metal nanoparticles within photovoltaic devices was studied. This self-assembly method provides excellent control over both nanoparticle size and surface coverage. Films of spherical Ag nanoparticles with diameter of ?100 nm were

  19. Sintering effect on the optoelectronic characteristics of HgSe nanoparticle films on plastic substrates

    International Nuclear Information System (INIS)

    Byun, Kwangsub; Cho, Kyoungah; Kim, Sangsig

    2010-01-01

    The optoelectronic characteristics of HgSe nanoparticle films spin-coated on flexible plastic substrates are investigated under the illumination of 1.3 μm wavelength light. The sintering process improves the optoelectronic characteristics of the HgSe nanoparticle films. The photocurrent of the sintered HgSe nanoparticle films under the illumination of 1.3 μm wavelength light is approximately 20 times larger in magnitude than that of the non-sintered films in air at room temperature. Moreover, the endurance of the flexible optoelectronic device investigated by the continuous substrate bending test reveals that the photocurrent efficiency changes negligibly up to 250 cycles.

  20. Ultrathin free-standing close-packed gold nanoparticle films: Conductivity and Raman scattering enhancement

    Science.gov (United States)

    Yu, Qing; Huang, Hongwen; Peng, Xinsheng; Ye, Zhizhen

    2011-09-01

    A simple filtration technique was developed to prepare large scale free-standing close-packed gold nanoparticle ultrathin films using metal hydroxide nanostrands as both barrier layer and sacrificial layer. As thin as 70 nm, centimeter scale robust free-standing gold nanoparticle thin film was obtained. The thickness of the films could be easily tuned by the filtration volumes. The electronic conductivities of these films varied with the size of the gold nanoparticles, post-treatment temperature, and thickness, respectively. The conductivity of the film prepared from 20 nm gold nanoparticles is higher than that of the film prepared from 40 nm gold nanoparticle by filtering the same filtration volume of their solution, respectively. Their conductivities are comparable to that of the 220 nm thick ITO film. Furthermore, these films demonstrated an average surface Raman scattering enhancement up to 6.59 × 105 for Rhodamine 6 G molecules on the film prepared from 40 nm gold nanoparticles. Due to a lot of nano interspaces generated from the close-packed structures, two abnormal enhancements and relative stronger intensities of the asymmetrical vibrations at 1534 and 1594 cm-1 of R6G were observed, respectively. These robust free-standing gold nanoparticle films could be easily transferred onto various solid substrates and hold the potential application for electrodes and surface enhanced Raman detectors. This method is applicable for preparation of other nanoparticle free-standing thin films.A simple filtration technique was developed to prepare large scale free-standing close-packed gold nanoparticle ultrathin films using metal hydroxide nanostrands as both barrier layer and sacrificial layer. As thin as 70 nm, centimeter scale robust free-standing gold nanoparticle thin film was obtained. The thickness of the films could be easily tuned by the filtration volumes. The electronic conductivities of these films varied with the size of the gold nanoparticles, post

  1. Interfacial passivation of CdS layer to CdSe quantum dots-sensitized electrodeposited ZnO nanowire thin films

    International Nuclear Information System (INIS)

    Zhang, Jingbo; Sun, Chuanzhen; Bai, Shouli; Luo, Ruixian; Chen, Aifan; Sun, Lina; Lin, Yuan

    2013-01-01

    ZnO porous thin films with nanowire structure were deposited by the one-step electrochemical deposition method. And a CdS layer was coated on the as-deposited ZnO nanowire thin films by successive ionic layer adsorption and reaction (SILAR) method to passivate surface states. Then the films were further sensitized by CdSe quantum dots (QDs) to serve as a photoanode for fabricating quantum dots-sensitized solar cells (QDSSCs). The effect of the CdS interfacial passivation layer on the performance of the QDSSCs was systematically investigated by varying the SILAR cycle number and heating the passivation layer. The amorphous CdS layer with an optimized thickness can effectively suppress the recombination of the injected electrons with holes on QDs and the redox electrolyte. The newly formed CdS layer on the surface of the ZnO nanowire thin film obviously prolongs the electron lifetime in the passivated ZnO nanoporous thin film because of the lower surface trap density in the ZnO nanowires after CdS deposition, which is favorable to the higher short-circuit photocurrent density (J sc ). For the CdSe QDs-sensitized ZnO nanoporous thin film with the interfacial passivation layer, the J sc and conversion efficiency can reach a maximum of 8.36 mA cm −2 and 2.36%, respectively. The conversion efficiency was improved by 83.47% compared with that of the cell based on the CdSe QDs-sensitized ZnO nanoporous thin film without CdS interfacial passivation (0.39%)

  2. Decorating TiO2 Nanowires with BaTiO3 Nanoparticles: A New Approach Leading to Substantially Enhanced Energy Storage Capability of High-k Polymer Nanocomposites.

    Science.gov (United States)

    Kang, Da; Wang, Guanyao; Huang, Yanhui; Jiang, Pingkai; Huang, Xingyi

    2018-01-31

    The urgent demand of high energy density and high power density devices has triggered significant interest in high dielectric constant (high-k) flexible nanocomposites comprising dielectric polymer and high-k inorganic nanofiller. However, the large electrical mismatch between polymer and nanofiller usually leads to earlier electric failure of the nanocomposites, resulting in an undesirable decrease of electrical energy storage capability. A few studies show that the introduction of moderate-k shell onto a high-k nanofiller surface can decrease the dielectric constant mismatch, and thus, the corresponding nanocomposites can withstand high electric field. Unfortunately, the low apparent dielectric enhancement of the nanocomposites and high electrical conductivity mismatch between matrix and nanofiller still result in low energy density and low efficiency. In this study, it is demonstrated that encapsulating moderate-k nanofiller with high-k but low electrical conductivity shell is effective to significantly enhance the energy storage capability of dielectric polymer nanocomposites. Specifically, using BaTiO 3 nanoparticles encapsulated TiO 2 (BaTiO 3 @TiO 2 ) core-shell nanowires as filler, the corresponding poly(vinylidene fluoride-co-hexafluoropylene) nanocomposites exhibit superior energy storage capability in comparison with the nanocomposites filled by either BaTiO 3 or TiO 2 nanowires. The nanocomposite film with 5 wt % BaTiO 3 @TiO 2 nanowires possesses an ultrahigh discharged energy density of 9.95 J cm -3 at 500 MV m -1 , much higher than that of commercial biaxial-oriented polypropylene (BOPP) (3.56 J cm -3 at 600 MV m -1 ). This new strategy and corresponding results presented here provide new insights into the design of dielectric polymer nanocomposites with high electrical energy storage capability.

  3. Preparation and Characterization of Thin-Film Composite Membrane with Nanowire-Modified Support for Forward Osmosis Process

    Science.gov (United States)

    Low, Ze-Xian; Liu, Qi; Shamsaei, Ezzatollah; Zhang, Xiwang; Wang, Huanting

    2015-01-01

    Internal concentration polarization (ICP) in forward osmosis (FO) process is a characteristic problem for asymmetric thin-film composite (TFC) FO membrane which leads to lower water flux. To mitigate the ICP effect, modification of the substrates’ properties has been one of the most effective methods. A new polyethersulfone-based ultrafiltration membrane with increased surface porosity and high water flux was recently produced by incorporating Zn2GeO4 nanowires. The composite membrane was used as a substrate for the fabrication of TFC FO membrane, by coating a thin layer of polyamide on top of the substrate. The substrate and the nanowires were characterized by a range of techniques such as SEM, XRD, and contact angle goniometry. The water permeability and molecular weight cut-offs (MWCO) of the substrate; and the FO performance of the TFC membrane were also determined. The Zn2GeO4-modified membrane showed ~45% increase in water permeability and NaCl salt rejection of 80% under RO mode. In FO mode, the ratio of water flux to reverse solute flux was also improved. However, lower FO flux was obtained which could be due to ICP. The result shows that Zn2GO4 nanowire may be used as a modifier to the substrate to improve the quality of the polyamide layer on the substrate to improve the flux and selectivity, but not as effective in reducing ICP. This work demonstrates that the incorporation of nanomaterials to the membrane substrate may be an alternative approach to improve the formation of polyamide skin layer to achieve better FO performance. PMID:25803239

  4. Preparation and Characterization of Thin-Film Composite Membrane with Nanowire-Modified Support for Forward Osmosis Process

    Directory of Open Access Journals (Sweden)

    Ze-Xian Low

    2015-03-01

    Full Text Available Internal concentration polarization (ICP in forward osmosis (FO process is a characteristic problem for asymmetric thin-film composite (TFC FO membrane which leads to lower water flux. To mitigate the ICP effect, modification of the substrates’ properties has been one of the most effective methods. A new polyethersulfone-based ultrafiltration membrane with increased surface porosity and high water flux was recently produced by incorporating Zn2GeO4 nanowires. The composite membrane was used as a substrate for the fabrication of TFC FO membrane, by coating a thin layer of polyamide on top of the substrate. The substrate and the nanowires were characterized by a range of techniques such as SEM, XRD, and contact angle goniometry. The water permeability and molecular weight cut-offs (MWCO of the substrate; and the FO performance of the TFC membrane were also determined. The Zn2GeO4-modified membrane showed ~45% increase in water permeability and NaCl salt rejection of 80% under RO mode. In FO mode, the ratio of water flux to reverse solute flux was also improved. However, lower FO flux was obtained which could be due to ICP. The result shows that Zn2GO4 nanowire may be used as a modifier to the substrate to improve the quality of the polyamide layer on the substrate to improve the flux and selectivity, but not as effective in reducing ICP. This work demonstrates that the incorporation of nanomaterials to the membrane substrate may be an alternative approach to improve the formation of polyamide skin layer to achieve better FO performance.

  5. Fe nanoparticle tailored poly(N-methyl pyrrole) nanowire matrix: a CHEMFET study from the perspective of discrimination among electron donating analytes

    International Nuclear Information System (INIS)

    Datta, K; Rushi, A; Shirsat, M; Mulchandani, A; Ghosh, P

    2015-01-01

    Back-gated chemically sensitive field effect transistor (CHEMFET) platforms have been developed with electrochemically synthesized poly(N-methyl pyrrole) nanowires by a templateless route. The nanowire matrix has been tailored with Fe nanoparticles to probe their effect in enhancing the sensing capabilities of the nanowire platform, and further to see if the inculcation of Fe nanoparticles is helpful to enhance the screening capability of the sensor among electron donating analytes. A noticeable difference in the sensing behaviour of the CHEMFET sensor was observed when it was exposed to three different analytes—ammonia, phosphine and carbon monoxide. FET transfer characteristics were instrumental in the corroboration of the experimental validations. The observations have been rationalized considering the simultaneous modulation of the work functions of Fe and polymeric material. The real time behaviour of the sensor shows that the sensor platform is readily capable of sensing the validated analytes at a ppb level of concentration with good response and recovery behaviour. The best response could be observed for ammonia with an Fe nanoparticle tailored polymeric matrix, with a sensitivity of ∼31.58% and excellent linearity (R 2 = 0.985) in a concentration window of 0.05 ppm to 1 ppm. (paper)

  6. Film Formation of Ag Nanoparticles at the Organic-Aqueous Liquid Interface

    Science.gov (United States)

    Vigorita, John

    2005-03-01

    A wet-chemical method to make films by spontaneous assembly of passivated Ag nanoparticles at the organic-aqueous liquid interface is presented. The interfacial films exhibit a blue opalescence, or in other cases a silvery color, and are characterized with transmission electron microscopy and UV-visible spectrophotometry. Measurements indicate that nanoparticles in the interfacial film can form superlattices and in some cases nanostructures.

  7. Enhanced output performance of a lead-free nanocomposite generator using BaTiO3 nanoparticles and nanowires filler

    Science.gov (United States)

    Baek, Changyeon; Yun, Jong Hyuk; Wang, Hee Seung; Wang, Ji Eun; Park, Hyeonbin; Park, Kwi-Il; Kim, Do Kyung

    2018-01-01

    Flexible nanocomposite generators based on piezoelectric nanoparticles (NPs)-polymeric matrix have been attracted attention as the energy harvesting device converted the electricity from the mechanical deformations. To enhance the piezo-potential difference introduced inside the piezoelectric nanocomposite, one-dimensional nanostructures such as CNTs, copper nanorods, and Ag nanowires (NWs) should be used inevitably as a dispersing agent for achieving well-distributed piezoelectric nanoparticles in an elastomer. These non-piezoelectric additives showed versatile roles; however, their toxicity to living organism has been an obstacle to realize the bio-eco-friendly flexible energy harvesters. Replacing them with piezoelectric NWs with non-toxic can be a challengeable approach to achieve not only the original purposes of additives but also the improvement of output performance. Here, we synthesized well-crystallized BaTiO3 spherical and acicular NPs via a simple hydrothermal reaction and the two-step hydrothermal reactions, respectively and produced piezoelectric nanocomposite made of piezoelectric BaTiO3 NPs and NWs without toxic dispersion enhancers. Output performance of the fabricated flexible energy harvesters with varying the composition of NPs and NWs were investigated by the well-optimized measurement system during the periodical bending and unbending. A nanocomposite-based energy harvester with 4:1 wt ratio generated the maximum open-circuit voltage and short-circuit current of 60 V and 1.1 μA, respectively.

  8. Elastic Moduli of Nanoparticle-Polymer Composite Thin Films via Buckling on Elastomeric Substrates

    Science.gov (United States)

    Yuan, Hongyi; Karim, Alamgir; University of Akron Team

    2011-03-01

    Polymeric thin films find applications in diverse areas such as coatings, barriers and packaging. The dispersion of nanoparticles into the films was proven to be an effective method to generate tunable properties, particularly mechanical strength. However, there are very few methods for mechanical characterization of the composite thin films with high accuracy. In this study, nanometric polystyrene and polyvinyl alcohol films with uniformly dispersed cobalt and Cloisite nanoparticles at varying concentrations were synthesized via flow-coating and then transferred to crosslinked polydimethylsiloxane (PDMS) flexible substrates. The technique of Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) was employed to determine the elastic moduli of the films, which were calculated from the buckling patterns generated by applying compressive stresses. Results on moduli of films as a function of the concentrations of nanoparticles and the thicknesses of the composite films will be presented. *Corresponding author: alamgir@uakron.edu

  9. Tribological behavior of in situ Ag nanoparticles/polyelectrolyte composite molecular deposition films

    International Nuclear Information System (INIS)

    Guo Yanbao; Wang Deguo; Liu Shuhai

    2010-01-01

    Multilayer polyelectrolyte films containing silver ions were obtained by molecular deposition method on a glass plate or a quartz substrate. The in situ Ag nanoparticles were synthesized in the multilayer polyelectrolyte films which were put into fresh NaBH 4 aqueous solution. The structure and surface morphology of composite molecular deposition films were observed by UV-vis spectrophotometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Tribological characteristic was investigated by AFM and micro-tribometer. It was found that the in situ Ag nanoparticles/polyelectrolyte composite molecular deposition films have lower coefficient of friction and higher anti-wear life than pure polyelectrolyte molecular deposition films.

  10. Growth Mechanism of Nanowires: Binary and Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Su, Ching-Hua; Hopkins, R. H.; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    Semiconductor nanowires exhibit very exciting optical and electrical properties including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here the mechanism of nanowire growth from the melt-liquid-vapor medium. We describe preliminary results of binary and ternary selenide materials in light of recent theories. Experiments were performed with lead selenide and thallium arsenic selenide systems which are multifunctional material and have been used for detectors, acousto-optical, nonlinear and radiation detection applications. We observed that small units of nanocubes and elongated nanoparticles arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places. Growth of lead selenide nanowires was performed by physical vapor transport method and thallium arsenic selenide nanowire by vapor-liquid-solid (VLS) method. In some cases very long wires (>mm) are formed. To achieve this goal experiments were performed to create situation where nanowires grew on the surface of solid thallium arsenic selenide itself.

  11. Percolation model for electron conduction in films of metal nanoparticles linked by organic molecules

    International Nuclear Information System (INIS)

    Muller, K.H.; Herrmann, J.; Raguse, B.; Baxter, G.; Reda, T.

    2002-01-01

    Full text: We have investigated theoretically and experimentally the temperature dependence of the conductance of films of Au nanoparticles linked by alkane dithiol molecules in the temperature range between 5 K and 300 K. Conduction in these films is due to tunneling of single electrons between neighbouring metal nanoparticles. During tunnelling an electron has to overcome the Coulomb charging energy. We find that the observed temperature dependence of the conductance is non-Arrhenius like and can be described in terms of a percolation theory which takes account of disorder in the system. Disorder in our nanoparticle films is caused by variations in the nanoparticle size, fluctuations in the separation gaps between adjacent nanoparticles and by offset charges. To explain in detail our experimental data, a wide distribution of separation gaps and charging energies is needed. We find that a wide Coulomb charging energy distribution can arise from random offset charges even if the nanoparticle size distribution is narrow

  12. Gold nanoparticles and films produced by a laser ablation/gas deposition (LAGD) method

    International Nuclear Information System (INIS)

    Kawakami, Yuji; Seto, Takafumi; Yoshida, Toshinobu; Ozawa, Eiichi

    2002-01-01

    Gold nanoparticles have great potential for various nanoelectronic applications such as single electron transistors, an infrared absorption sensor and so on. It is very important to understand and control the size distribution of the particles for such a variety of applications. In this paper, we report the size distribution of gold nanoparticles and the relationship between the nanoparticle-films and the electrical property produced by a laser ablation method. Gold nanoparticle-films were prepared by a technique, which sprays nanoparticles on the substrate through a nozzle. We call it a gas deposition method. The nanoparticles were generated by the nanosecond pulsed Nd:YAG laser ablation of a gold substrate under a low-pressure inert gas atmosphere. The ambient pressure was changed to control the average size and their distribution. The particles produced in the generation chamber were transported by a helium carrier gas to the deposition chamber and deposited on a substrate to form the films composed of gold nanoparticles. The electrical resistivity of the generated gold nanoparticle-films on the glass substrates was measured using a four-probe method. The size distribution of the nanoparticles was examined using transmission electron microscopy (TEM) and a low-pressure differential mobility analyzer (LP-DMA). The relationship between the particle size and the electrical properties of each film made by the different synthesis conditions were analyzed. The electrical resistivity changed from the order of 10 -5 to 10 -1 Ω cm depending on the ambient pressure and the size distribution

  13. Material influence on hot spot distribution in the nanoparticle heterodimer on film

    Science.gov (United States)

    Chen, Fang; Huang, Yingzhou; Wei, Hua; Wang, Shuxia; Zeng, Xiping; Cao, Wenbin; Wen, Weijia

    2018-04-01

    The metal nanoparticle aggregated on film, as an effective plasma enhancement pathway, has been widely used in various surface plasmon-related fields. In this study, the hot spots on the metal nanoparticle dimer composed of different materials (Agsbnd Au, Agsbnd Pd, and Agsbnd Cu) on metal (Au) film were investigated with finite element method. Based on the results, the hot spot distribution affected by the material can be confirmed by the electric field distribution of the metal nanoparticle dimer on the film. The aggregation effects of Au and Ag nanoparticles in Ausbnd Ag dimer system are not significant. However, for the Pdsbnd Ag dimer system, the hot spot aggregation effect is slightly larger than that of the Pd nanoparticle under the Ag nanoparticle. Besides, the non-uniform hot spots would bring about the light focusing phenomenon that the light intensity under Ag nanoparticle is almost 100 times greater than that under Cu nanoparticle in Agsbnd Cu dimer system. These results were further confirmed by the surface charge distribution, and analyzed based on the plasmonic hybridization theory. The data about the nanoparticle dimer on the dielectric (Si) film demonstrate the importance of induced image charges on the film surface in such a light focusing phenomenon. Our findings can enhance the understanding of the surface plasmon coupling in different materials, which may have great application prospects in surface plasmon-related fields, such as SERS, plasmonic enhanced solar cell, and plasmonic sensoring, etc.

  14. Sub-10 ohm resistance gold films prepared by removal of ligands from thiol-stabilized 6 nm gold nanoparticles.

    Science.gov (United States)

    Sugden, Mark W; Richardson, Tim H; Leggett, Graham

    2010-03-16

    The optical and electrical properties of dodecanethiol-stabilized nanoparticles (6 nm diameter gold core) have been investigated over a range of film thicknesses and temperatures. The surface plasmon resonance absorbance is found to be dependent on temperature. Heating of the nanoparticle film causes desorption of the thiol from the surface of the gold nanoparticle, resulting in irreversible changes to the absorption spectra of the nanoparticle film. Atomic force microscopy images of the samples before and after heating for different film thicknesses reveal structural changes and increased domain connectivity for thicker films leading to sub-10 ohm resistances measured for the 15-layer film.

  15. Fabrication of molecular hybrid films of gold nanoparticle and polythiophene by covalent assembly

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthy, Jayaraman, E-mail: jsu2@np.edu.sg [Department of Chemical & Biomolecular Engineering, National University of Singapore, Block E5, 4 Engineering Drive 4, 117576 (Singapore); Environmental & Water Technology Centre of Innovation, Ngee Ann Polytechnic, 599489 (Singapore); Dharmarajan, Rajarathnam [CERAR, University of South Australia, Mawson Lakes, SA 5095 (Australia); Srinivasan, M.P., E-mail: chesmp@nus.edu.sg [Department of Chemical & Biomolecular Engineering, National University of Singapore, Block E5, 4 Engineering Drive 4, 117576 (Singapore)

    2015-08-31

    This work demonstrates the fabrication of molecular hybrid films comprising gold nanoparticles (AuNPs) incorporated in covalently assembled, substituted polythiophene (poly(3-(2-bromoethoxy)ethoxymethylthiophene-2,5-diyl (PBrEEMT))) films by different surface chemistry routes. AuNPs are incorporated in the immobilized polythiophene matrix due to its affinity for amine and sulfur. The amount of AuNPs present depends on the nature of the incorporation, the extent of film coverage and interaction of thiophene and amine groups. PBrEEMT films functionalized with amine rich polyallylamine immobilize greater numbers of AuNPs due to more extensive gold–amine interactions. Covalent binding between AuNP and PBrEEMT films was accomplished by using pre-functionalised AuNPs (4-aminothiophenol functionalized AuNPs). Atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to study the morphology and chemical constituents of assembled films. These approaches will pave the way for developing facile methods for nanoparticle incorporation and will also facilitate direct interaction of nanoparticles with the conducting polymer matrix and enhance the electrical properties of the films. - Highlights: • Covalent molecular assembly enabled the fabrication of molecular hybrid films. • Monomeric and polymeric species were employed as intermediate linkers. • Adopted approaches facilitated the direct interaction of gold nanoparticle in films. • The amount of nanoparticle incorporation depended on the extent of film coverage.

  16. Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles

    Science.gov (United States)

    Sun, Qingjie; Xi, Tingting; Li, Ying; Xiong, Liu

    2014-01-01

    The characterization of corn starch (CS) films impregnated with CaCO3 nanoparticles was investigated. Criteria such as morphology, crystallinity, water vapor permeability (WVP), opacity, and mechanical properties were the focus of the investigation. It was found that the CaCO3 contents had significant effects on the tensile properties of the nanocomposite films. The addition of CaCO3 nanoparticles to the CS films significantly increased tensile strength from 1.40 to 2.24 MPa, elongation from 79.21 to 118.98%, and Young’s modulus from 1.82 to 2.41 MPa. The incorporation of CaCO3 nanoparticles increased the opacity of films, lowered the degree of WVP and film solubility value compared to those of the CS films. The results of scanning electron microscopy (SEM) showed that with the increase of CaCO3 nanoparticles content in starch films, the roughness of the films increased, and pores or cavities were found on the surface of the films, while small cracks were observed in the structures of the fractured surfaces. X-ray diffraction showed that the addition of nanoparticles increased the peaks in the intensity of films. PMID:25188503

  17. Layer-by-Layer Nanoassembly of Copper Indium Gallium Selenium Nanoparticle Films for Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    A. Hemati

    2012-01-01

    Full Text Available Thin films of CIGS nanoparticles interdigited with polymers have been fabricated through a cost-effective nonvacuum film deposition process called layer-by-layer (LbL nanoassembly. CIGS nanoparticles synthesized by heating copper chloride, indium chloride, gallium chloride, and selenium in oleylamine were dispersed in water, and desired surface charges were obtained through pH regulation and by coating the particles with polystyrene sulfonate (PSS. Raising the pH of the nanoparticle dispersion reduced the zeta-potential from +61 mV at pH 7 to −51 mV at pH 10.5. Coating the CIGS nanoparticles with PSS (CIGS-PSS produced a stable dispersion in water with −56.9 mV zeta-potential. Thin films of oppositely charged CIGS nanoparticles (CIGS/CIGS, CIGS nanoparticles and PSS (CIGS/PSS, and PSS-coated CIGS nanoparticles and polyethylenimine (CIGS-PSS/PEI were constructed through the LbL nanoassembly. Film thickness and resistivity of each bilayer of the films were measured, and photoelectric properties of the films were studied for solar cell applications. Solar cell devices fabricated with a 219 nm CIGS film, when illuminated by 50 W light-source, produced 0.7 V open circuit voltage and 0.3 mA/cm2 short circuit current density.

  18. Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO_3 nanoparticles

    International Nuclear Information System (INIS)

    Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

    2016-01-01

    Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO_2 nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

  19. Hexagonally ordered nanoparticles templated using a block copolymer film through Coulombic interactions

    International Nuclear Information System (INIS)

    Lee, Wonjoo; Lee, Seung Yong; Zhang Xin; Rabin, Oded; Briber, R M

    2013-01-01

    We present a novel and simple method for forming hexagonal gold nanoparticle arrays that uses Coulombic interactions between negatively charged gold nanoparticles on positively charged vertically oriented poly(4-vinylpyridine) cylinders formed in a spin cast polystyrene-b-poly(4-vinylpyridine) block copolymer film. Exposure of the block copolymer film to dibromobutane vapor quaternizes and crosslinks the poly(4-vinylpyridine) domains which allows for the templated deposition of gold nanoparticles into a self-assembled hexagonal array through electrostatic interactions. These systems can form the basis for sensors or next generation nanoparticle based electronics. (paper)

  20. Multiscale patterning of nanocomposite polyelectrolyte/nanoparticle films using inkjet printing and AFM scratching

    International Nuclear Information System (INIS)

    Leigh, S J; Bowen, J; Preece, J A

    2015-01-01

    The fabrication of structured polymer/nanoparticle composite films through a combination of additive, subtractive and self-assembly methodologies is investigated. Consumer grade inkjet printing hardware is employed to deposit cationic polyelectrolytes on (i) hydrophilic and (ii) hydrophobised glass substrates. The hydrophobisation process controls the spreading of the droplets and hence the lateral size of printed features. The printed cationic polyelectrolyte regions are used as a template to direct the self-assembly of negatively charged gold nanoparticles onto the surface. Micro-scale features are created in the polyelectrolyte/nanoparticle films using AFM scratching to selectively displace material. The effect of substrate wettability on film morphology is discussed. (paper)

  1. Ultradense, Deep Subwavelength Nanowire Array Photovoltaics As Engineered Optical Thin Films

    KAUST Repository

    Tham, Douglas

    2010-11-10

    A photovoltaic device comprised of an array of 20 nm wide, 32 nm pitch array of silicon nanowires is modeled as an optical material. The nanowire array (NWA) has characteristic device features that are deep in the subwavelength regime for light, which permits a number of simplifying approximations. Using photocurrent measurements as a probe of the absorptance, we show that the NWA optical properties can be accurately modeled with rigorous coupled-wave analysis. The densely structured NWAs behave as homogeneous birefringent materials into the ultraviolet with effective optical properties that are accurately modeled using the dielectric functions of bulk Si and SiO 2, coupled with a physical model for the NWA derived from ellipsometry and transmission electron microscopy. © 2010 American Chemical Society.

  2. Theory of space charge limited currents in films and nanowires with dopants

    Science.gov (United States)

    Zhang, Xiaoguang; Pantelides, Sokrates

    2015-03-01

    We show that proper description of the space charge limited currents (SCLC) in a homogeneous bulk material must account fully for the effect of the dopants and the interplay between dopants and traps. The sharp rise in the current at the trap-filled-limit (TFL) is partially mitigated by the dopant energy levels and the Frenkel effect, namely the lowering of the ionization energy by the electric field, which is screened by the free carriers. In nanowires, lack of effective screening causes the trap occupation at small biases to reach a high level comparable to the TFL in bulk. This explains the high current density in SCLCs observed in nanowires. This work is supported by the LDRD program at ORNL. Portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

  3. Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties.

    Science.gov (United States)

    Liu, Fei; Antoniou, John; Li, Yue; Yi, Jiang; Yokoyama, Wallace; Ma, Jianguo; Zhong, Fang

    2015-04-22

    Gelatin films incorporated with chitosan nanoparticles in various free/encapsulated tea polyphenol (TP) ratios were prepared in order to investigate the influence of different ratios on the physicochemical and antioxidant properties of films. The TP-containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutyl ether-β-cyclodextrin sodium (SBE-β-CD) at three different encapsulation efficiencies (EE; ∼50%, ∼80%, and ∼100%) of TP. The stability of TP-loaded nanoparticles was maintained during the film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects, while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP-loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflower oil packaged in bags made of gelatin films embedded with nanoparticles of 80% EE showed the best oxidation inhibitory effect, followed by 100% EE, 50% EE, and free TP, over 6 weeks of storage. However, when the gelatin film was placed over the headspace and was not in contact with the oil, the free TP showed the best effect. The results indicate that sustained release of TP in the contacting surface can ensure the protective effects, which vary with free/encapsulated mass ratios, thus improving antioxidant activities instead of increasing the dosage.

  4. Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

    Science.gov (United States)

    Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

    2013-07-25

    We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. The Roll of NaPSS Surfactant on the Ceria Nanoparticles Embedding in Polypyrrole Films

    Directory of Open Access Journals (Sweden)

    Simona Popescu

    2016-01-01

    Full Text Available Cerium oxide nanoparticles (CeO2 NPs in crystalline form have been synthesized by a coprecipitation method. CeO2 nanoparticles were then embedded in polypyrrole (PPy films during the electropolymerization of pyrrole (Py on titanium substrate. The influence of poly(sodium 4-styrenesulfonate (NaPSS surfactant used during polymerization on the embedding of CeO2 NPs in polypyrrole films was investigated. The new films were characterized in terms of surface analysis, wettability, electrochemical behaviour, and antibacterial effect. The surface and electrochemical characterization revealed the role of surfactant on PPy doping process cerium oxide incorporation. In the presence of surfactant, CeO2 NPs are preferentially embedded in the polymeric film while, without surfactant, the ceria nanoparticles are quasiuniformly spread as agglomerates onto polymeric films. The antibacterial effect of studied PPy films was substantially improved in the presence of cerium oxide and depends by the polymerization conditions.

  6. Electrocatalytic glucose oxidation at gold and gold-carbon nanoparticulate film prepared from oppositely charged nanoparticles

    International Nuclear Information System (INIS)

    Karczmarczyk, Aleksandra; Celebanska, Anna; Nogala, Wojciech; Sashuk, Volodymyr; Chernyaeva, Olga; Opallo, Marcin

    2014-01-01

    Graphical abstract: - Highlights: • Gold nanoparticulate film electrodes were prepared by layer-by-layer method from oppositely charged nanoparticles. • Positively charged nanoparticles play dominant role in glucose oxidation in alkaline solution. • Gold and gold-carbon nanoparticulate film electrodes exhibit similar glucose oxidation current and onset potential. - Abstract: Electrocatalytic oxidation of glucose was studied at nanoparticulate gold and gold-carbon film electrodes. These electrodes were prepared by a layer-by-layer method without application of any linker molecules. Gold nanoparticles were stabilized by undecane thiols functionalized by trimethyl ammonium or carboxylate groups, whereas the carbon nanoparticles were covered by phenylsulfonate functionalities. The gold nanoparticulate electrodes were characterized by UV-vis and XPS spectroscopy, atomic force microscopy and voltammetry, before and after heat-treatment. Heat-treatment facilitates the aggregation of the nanoparticles and affects the structure of the film. The comparison of the results obtained with film electrodes prepared from gold nanoparticles with the same charge and with gold-carbon nanoparticulate electrodes, proved that positively charged nanoparticles are responsible for the high electrocatalytic activity, whereas negatively charged ones act rather as a linker of the film

  7. High performance flexible metal oxide/silver nanowire based transparent conductive films by a scalable lamination-assisted solution method

    Directory of Open Access Journals (Sweden)

    Hua Yu

    2017-03-01

    Full Text Available Flexible MoO3/silver nanowire (AgNW/MoO3/TiO2/Epoxy electrodes with comparable performance to ITO were fabricated by a scalable solution-processed method with lamination assistance for transparent and conductive applications. Silver nanoparticle-based electrodes were also prepared for comparison. Using a simple spin-coating and lamination-assisted planarization method, a full solution-based approach allows preparation of AgNW-based composite electrodes at temperatures as low as 140 °C. The resulting flexible AgNW-based electrodes exhibit higher transmittance of 82% at 550 nm and lower sheet resistance about 12–15 Ω sq−1, in comparison with the values of 68% and 22–25 Ω sq−1 separately for AgNP based electrodes. Scanning electron microscopy (SEM and Atomic force microscopy (AFM reveals that the multi-stacked metal-oxide layers embedded with the AgNWs possess lower surface roughness (<15 nm. The AgNW/MoO3 composite network could enhance the charge transport and collection efficiency by broadening the lateral conduction range due to the built of an efficient charge transport network with long-sized nanowire. In consideration of the manufacturing cost, the lamination-assisted solution-processed method is cost-effective and scalable, which is desire for large-area fabrication. While in view of the materials cost and comparable performance, this AgNW-based transparent and conductive electrodes is potential as an alternative to ITO for various optoelectronic applications.

  8. Ferrite Nanoparticles, Films, Single Crystals, and Metamaterials: High Frequency Applications

    International Nuclear Information System (INIS)

    Harris, V.

    2006-01-01

    Ferrite materials have long played an important role in power conditioning, conversion, and generation across a wide spectrum of frequencies (up to ten decades). They remain the preferred magnetic materials, having suitably low losses, for most applications above 1 MHz, and are the only viable materials for nonreciprocal magnetic microwave and millimeter-wave devices (including tunable filters, isolators, phase shifters, and circulators). Recently, novel processing techniques have led to a resurgence of research interest in the design and processing of ferrite materials as nanoparticles, films, single crystals, and metamaterials. These latest developments have set the stage for their use in emerging technologies that include cancer remediation therapies such as magnetohyperthermia, magnetic targeted drug delivery, and magneto-rheological fluids, as well as enhanced magnetic resonance imaging. With reduced dimensionality of nanoparticles and films, and the inherent nonequilibrium nature of many processing schemes, changes in local chemistry and structure have profound effects on the functional properties and performance of ferrites. In this lecture, we will explore these effects upon the fundamental magnetic and electronic properties of ferrites. Density functional theory will be applied to predict the properties of these ferrites, with synchrotron radiation techniques used to elucidate the chemical and structural short-range order. This approach will be extended to study the atomic design of ferrites by alternating target laser-ablation deposition. Recently, this approach has been shown to produce ferrites that offer attractive properties not found in conventionally grown ferrites. We will explore the latest research developments involving ferrites as related to microwave and millimeter-wave applications and the attempt to integrate these materials with semiconductor materials platforms

  9. Dynamic mechanical behaviour of nanoparticle loaded biodegradable PVA films for vaginal drug delivery.

    Science.gov (United States)

    Traore, Yannick L; Fumakia, Miral; Gu, Jijin; Ho, Emmanuel A

    2018-03-01

    In this study, we investigated the viscoelastic and mechanical behaviour of polyvinyl alcohol films formulated along with carrageenan, plasticizing agents (polyethylene glycol and glycerol), and when loaded with nanoparticles as a model for potential applications as microbicides. The storage modulus, loss modulus and glass transition temperature were determined using a dynamic mechanical analyzer. Films fabricated from 2% to 5% polyvinyl alcohol containing 3 mg or 5 mg of fluorescently labeled nanoparticles were evaluated. The storage modulus and loss modulus values of blank films were shown to be higher than the nanoparticle-loaded films. Glass transition temperature determined using the storage modulus, and loss modulus was between 40-50℃ and 35-40℃, respectively. The tensile properties evaluated showed that 2% polyvinyl alcohol films were more elastic but less resistant to breaking compared to 5% polyvinyl alcohol films (2% films break around 1 N load and 5% films break around 7 N load). To our knowledge, this is the first study to evaluate the influence of nanoparticle and film composition on the physico-mechanical properties of polymeric films for vaginal drug delivery.

  10. Nanowire Photovoltaic Devices

    Science.gov (United States)

    Forbes, David

    2015-01-01

    Firefly Technologies, in collaboration with the Rochester Institute of Technology and the University of Wisconsin-Madison, developed synthesis methods for highly strained nanowires. Two synthesis routes resulted in successful nanowire epitaxy: direct nucleation and growth on the substrate and a novel selective-epitaxy route based on nanolithography using diblock copolymers. The indium-arsenide (InAs) nanowires are implemented in situ within the epitaxy environment-a significant innovation relative to conventional semiconductor nanowire generation using ex situ gold nanoparticles. The introduction of these nanoscale features may enable an intermediate band solar cell while simultaneously increasing the effective absorption volume that can otherwise limit short-circuit current generated by thin quantized layers. The use of nanowires for photovoltaics decouples the absorption process from the current extraction process by virtue of the high aspect ratio. While no functional solar cells resulted from this effort, considerable fundamental understanding of the nanowire epitaxy kinetics and nanopatterning process was developed. This approach could, in principle, be an enabling technology for heterointegration of dissimilar materials. The technology also is applicable to virtual substrates. Incorporating nanowires onto a recrystallized germanium/metal foil substrate would potentially solve the problem of grain boundary shunting of generated carriers by restricting the cross-sectional area of the nanowire (tens of nanometers in diameter) to sizes smaller than the recrystallized grains (0.5 to 1 micron(exp 2).

  11. Growth of Au nanoparticle films and the effect of nanoparticle shape on plasmon peak wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Horikoshi, S., E-mail: horikoshi@sstl.info; Matsumoto, N.; Kato, T. [Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-8656 (Japan); Omata, Y. [Application and Technical Support, Elionix, Inc., 3-7-6 Motoyokoyama Hachioji, Tokyo 192-0063 (Japan)

    2014-05-21

    Metal nanoparticles (NPs) exhibit localized surface plasmon resonance (LSPR) and thus have potential for use in a wide range of applications. A facile technique for the preparation of NP films using an electron-cyclotron-resonance plasma sputtering method without a dewetting process is described. Field emission scanning electron microscopy (FE-SEM) observations revealed that the Au NPs grew independently as island-like particles during the first stage of sputtering and then coalesced with one another as sputtering time increased to ultimately form a continuous film. A plasmon absorption peak was observed via optical measurement of absorption efficiency. The LSPR peak shifted toward longer wavelengths (red shift) with an increase in sputtering time. The cause of this plasmon peak shift was theoretically investigated using the finite-difference time-domain calculation method. A realistic statistical distribution of the particle shapes based on FE-SEM observations was applied for the analysis, which has not been previously reported. It was determined that the change in the shape of the NPs from spheroidal to oval or slender due to coalescence with neighbouring NPs caused the LSPR peak shift. These results may enable the design of LSPR devices by controlling the characteristics of the nanoparticles, such as their size, shape, number density, and coverage.

  12. Growth of Au nanoparticle films and the effect of nanoparticle shape on plasmon peak wavelength

    Science.gov (United States)

    Horikoshi, S.; Matsumoto, N.; Omata, Y.; Kato, T.

    2014-05-01

    Metal nanoparticles (NPs) exhibit localized surface plasmon resonance (LSPR) and thus have potential for use in a wide range of applications. A facile technique for the preparation of NP films using an electron-cyclotron-resonance plasma sputtering method without a dewetting process is described. Field emission scanning electron microscopy (FE-SEM) observations revealed that the Au NPs grew independently as island-like particles during the first stage of sputtering and then coalesced with one another as sputtering time increased to ultimately form a continuous film. A plasmon absorption peak was observed via optical measurement of absorption efficiency. The LSPR peak shifted toward longer wavelengths (red shift) with an increase in sputtering time. The cause of this plasmon peak shift was theoretically investigated using the finite-difference time-domain calculation method. A realistic statistical distribution of the particle shapes based on FE-SEM observations was applied for the analysis, which has not been previously reported. It was determined that the change in the shape of the NPs from spheroidal to oval or slender due to coalescence with neighbouring NPs caused the LSPR peak shift. These results may enable the design of LSPR devices by controlling the characteristics of the nanoparticles, such as their size, shape, number density, and coverage.

  13. Determination of diffusion coefficient for released nanoparticles from developed gelatin/chitosan bilayered buccal films.

    Science.gov (United States)

    Mahdizadeh Barzoki, Zahra; Emam-Djomeh, Zahra; Mortazavian, Elaheh; Rafiee-Tehrani, Niyousha; Behmadi, Homa; Rafiee-Tehrani, Morteza; Moosavi-Movahedi, Ali Akbar

    2018-06-01

    This study aims at the mathematical optimization by Box-Behnken statistical design, fabrication by ionic gelation technique and in vitro characterization of insulin nanoparticles containing thiolated N- dimethyl ethyl chitosan (DMEC-Cys) conjugate. Then Optimized insulin nanoparticles were loaded into the buccal film, and in-vitro drug release from films was investigated, and diffusion coefficient was predicted. The optimized nanoparticles were shown to have mean particle size diameter of 148nm, zeta potential of 15.5mV, PdI of 0.26 and AE of 97.56%. Cell viability after incubation with optimized nanoparticles and films were assessed using an MTT biochemical assay. In vitro release study, FTIR and cytotoxicity also indicated that nanoparticles made of this thiolated polymer are suitable candidates for oral insulin delivery. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Effect of indium on photovoltaic property of n-ZnO/p-Si heterojunction device prepared using solution-synthesized ZnO nanowire film

    Science.gov (United States)

    Kathalingam, Adaikalam; Kim, Hyun-Seok; Park, Hyung-Moo; Valanarasu, Santiyagu; Mahalingam, Thaiyan

    2015-01-01

    Preparation of n-ZnO/p-Si heterostructures using solution-synthesized ZnO nanowire films and their photovoltaic characterization is reported. The solution-grown ZnO nanowire film is characterized using scanning electron microscope, electron dispersive x-ray, and optical absorption studies. Electrical and photovoltaic properties of the fabricated heterostructures are studied using e-beam-evaporated aluminum as metal contacts. In order to use transparent contact and to simultaneously collect the photogenerated carriers, sandwich-type solar cells were fabricated using ZnO nanorod films grown on p-silicon and indium tin oxide (ITO) coated glass as ITO/n-ZnO NR/p-Si. The electrical properties of these structures are analyzed from current-voltage (I-V) characteristics. ZnO nanowire film thickness-dependent photovoltaic properties are also studied. Indium metal was also deposited over the ZnO nanowires and its effects on the photovoltaic response of the devices were studied. The results demonstrated that all the samples exhibit a strong rectifying behavior indicating the diode nature of the devices. The sandwich-type ITO/n-ZnO NR/p-Si solar cells exhibit improved photovoltaic performance over the Al-metal-coated n-ZnO/p-Si structures. The indium deposition is found to show enhancement in photovoltaic behavior with a maximum open-circuit voltage (Voc) of 0.3 V and short-circuit current (Isc) of 70×10-6 A under ultraviolet light excitation.

  15. Incorporation of europium III complex into nanoparticles and films obtained by the Sol-Gel methodology

    Directory of Open Access Journals (Sweden)

    Faley Jean de Sousa

    2010-03-01

    Full Text Available The sol-gel process is very effective for the preparation of new materials with potential applications in optics, sensors, catalyst supports, coatings, and specialty inorganic polymers that can be used as hosts for the accommodation of organic molecules. The low temperature employed in the process is the main advantage of this methodology. In this work, the europium (III complex with 1,10-phenantroline was prepared, and this luminescent complex was incorporated into silica nanoparticles and films by the sol-gel process. The nanoparticles were obtained by the modified Stöber methodology. The films were obtained by the dip-coating technique, at different deposition rates and numbers of layers. The nanoparticles and films were characterized by photoluminescence, thermal analysis, and Raman and infrared spectroscopies. Characterization revealed that the europium (III complex was not affected upon incorporation into the nanoparticles and films, opening a new field for the application of these materials.

  16. Controlled fabrication of the strong emission YVO4:Eu3+ nanoparticles and nanowires by microwave assisted chemical synthesis

    International Nuclear Information System (INIS)

    Huong, Tran Thu; Vinh, Le Thi; Phuong, Ha Thi; Khuyen, Hoang Thi; Anh, Tran Kim; Tu, Vu Duc; Minh, Le Quoc

    2016-01-01

    In this report, we are presenting the controlled fabrication results of the strong emission YVO 4 : Eu 3+ nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO 4 : Eu 3+ prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO 4 : Eu 3+ nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of 5 D 0 – 7 F j (j=1, 2, 3, and 4) of Eu 3+ ions with the highest luminescence intensity of 5 D 0 → 7 F 2 transition. - Highlights: • The strong emission YVO 4 :Eu 3+ nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO 4 :Eu 3+ nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO 4 :Eu 3+ nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  17. Magnetization, magnetotransport and electron magnetic resonance studies of nanoparticles and nanowires of Pr0.5Sr0.5MnO3

    International Nuclear Information System (INIS)

    Rao, S S; Bhat, S V

    2009-01-01

    In this paper, we present the preparation and characterization of nanoparticles and nanowires of Pr 0.5 Sr 0.5 MnO 3 (PSMO). The main results of this investigation are as follows: (a) a comparison with the properties of the bulk material shows that the ferromagnetic (FM) transition at 270 K remains unaffected but the anti-ferromagnetic (AFM) transition at T N = 150 K disappears in the nanoparticles, (b) the size induced ground state magnetic phase (below 150 K) is predominantly FM, coexisting with a residual AFM phase, and (c) the temperature dependence of magnetic anisotropy shows complex behaviour, being higher in the nanoparticles at high temperatures and lower at moderately lower temperatures in comparison with the bulk. The results obtained from the extensive magnetization, magnetotransport and electron magnetic resonance studies made on various samples are presented and discussed in detail.

  18. Gold nanoparticles and polyethylene glycols functionalized conducting polyaniline nanowires for ultrasensitive and low fouling immunosensing of alpha-fetoprotein.

    Science.gov (United States)

    Hui, Ni; Sun, Xiaotian; Song, Zhiling; Niu, Shuyan; Luo, Xiliang

    2016-12-15

    An ultrasensitive biosensor for alpha-fetoprotein was developed based on electrochemically synthesized polyaniline (PANI) nanowires, which were functionalized with gold nanoparticles (AuNPs) and polyethylene glycols (PEG). The prepared PEG/AuNPs/PANI composite, combining the electrical conductivity of the AuNPs/PANI with the robust antifouling ability of PEG, offered an ideal substrate for the development of low fouling electrochemical biosensors. Alpha-fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker, was used as a model analyte, and its antibody was immobilized on the PEG/AuNPs/PANI for the construction of the AFP immunosensor. Using the redox current of PANI as the sensing signal, in addition to the good biocompatibility of PEG/AuNPs and the anti-biofouling property of PEG, the developed immunosensor showed improved biosensing performances, such as wide linear range and ultralow detection limit (0.007pgmL(-1)). More importantly, it is label-free, reagentless and low fouling, making it capable of assaying AFP in real serum samples without suffering from significant interference or biofouling. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. ZnO nanowire/TiO2 nanoparticle photoanodes prepared by the ultrasonic irradiation assisted dip-coating method

    International Nuclear Information System (INIS)

    Gan Xiaoyan; Li Xiaomin; Gao Xiangdong; Zhuge Fuwei; Yu Weidong

    2010-01-01

    Hybrid ZnO/TiO 2 photoanodes for dye-sensitized solar cells were prepared by combining ZnO nanowire (NW) arrays and TiO 2 nanoparticles (NPs) with the assistance of the ultrasonic irradiation assisted dip-coating method. Results show that the ultrasonic irradiation was an efficient way to promote the gap filling of TiO 2 NPs in the interstices of ZnO NWs. Hybrid ZnO NW/TiO 2 NP electrodes prepared with ultrasonic treatment exhibited better gap filling efficiency and higher visible absorptance. The overall conversion efficiency of the hybrid electrode was 0.79%, representing 35% improvement compared with that of the traditional one (0.58%). The enlarged surface area and improved attachments of TiO 2 NPs onto the walls of ZnO NWs induced by the application of ultrasonic irradiation may be the underlying reason. Electrochemical impedance spectroscopy measurements indicated that hybrid electrodes combined the advantages of improved electron transport along the ZnO NWs and increased surface area provided by infiltrated TiO 2 NPs, both of which are responsible for the improved cell efficiency.

  20. Controlled synthesis of TiO2-B nanowires and nanoparticles for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Qi Lihong; Liu Yongjun; Li Chunyan

    2010-01-01

    Controllable synthesis of the TiO 2 -B nanowires (NWs) and nanoparticles (NPs) had been achieved via a facile hydrothermal route, respectively, only by tuning the solution volume. The dye-sensitized solar cells prototypes had been fabricated using TiO 2 -B NW and NP electrodes, respectively. The TiO 2 -B NP cells had higher photocurrent and photoelectrical conversion efficiency than the TiO 2 -B NW cells though the latter exhibited larger photovoltage compared to the former. The key factors such as the photogenerated electron injection drive force, surface defects and the interfacial charge transfer, which determined the photoelectrical properties, had been systematically researched with the surface photovoltage spectra (SPS) and the electrochemical impedance spectra (EIS). The SPS proved that there was larger photoelectron injection drive force in TiO 2 -B NP photoelectrode than that in NW photoelectrode. And the electrochemical impedance spectra (EIS) revealed that TiO 2 -B NP cells had faster interface charge transfer compared to TiO 2 -B NW cells. Both proved that NP cells had the higher photocurrents.

  1. The Effects of in Situ-Formed Silver Nanoparticles on the Electrical Properties of Epoxy Resin Filled with Silver Nanowires

    Directory of Open Access Journals (Sweden)

    Gwang-Seok Song

    2016-04-01

    Full Text Available A novel method for preparing epoxy/silver nanocomposites was developed via the in situ formation of silver nanoparticles (AgNPs within the epoxy resin matrix while using silver nanowires (AgNWs as a conductive filler. The silver–imidazole complex was synthesized from silver acetate (AgAc and 1-(2-cyanoethyl-2-ethyl-4-methylimidazole (imidazole. AgNPs were generated in situ during the curing of the epoxy resin through the thermal decomposition of the AgAc–imidazole complex, which was capable of reducing Ag+ to Ag by itself. The released imidazole acted as a catalyst to cure the epoxy. Additionally, after the curing process, the in situ-generated AgNPs were stabilized by the formed epoxy network. Therefore, by using the thermal decomposition method, uniformly dispersed AgNPs of approximately 100 nm were formed in situ in the epoxy matrix filled with AgNWs. It was observed that the nanocomposites containing in situ-formed AgNPs exhibited isotropic electrical properties in the epoxy resins in the presence of AgNWs.

  2. Nanoparticle size and morphology control using ultrafast laser induced forward transfer of Ni thin films

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Abere, Michael J.; Schrider, Keegan J.; Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2013-08-26

    We have developed a nanoparticle (NP) printing technique using Ni thin film lift-off from glass substrates after ultrafast irradiation in air. Unique interactions of ultrafast laser pulses with thin films allow for control over NP faceting and size distributions. Control is achieved by changing the laser fluence, film thickness, and film-substrate distance. We demonstrate 20 nm Ni film removal from substrates and rapid NP printing, with size distributions centered at a 6 nm diameter. When the Ni film thickness is lowered to 10 nm, NPs are printed with distributions peaked at a 2 nm diameter.

  3. High-negative effective refractive index of silver nanoparticles system in nanocomposite films

    Science.gov (United States)

    Altunin, Konstantin K.; Gadomsky, Oleg N.

    2012-03-01

    We have proved on the basis of the experimental optical reflection and transmission spectra of the nanocomposite film of poly(methyl methacrylate) with silver nanoparticles that (PMMA + Ag) nanocomposite films have quasi-zero refractive indices in the optical wavelength range. We show that to achieve quasi-zero values of the complex index of refraction of composite materials is necessary to achieve high-negative effective refractive index in the system of spherical silver nanoparticles.

  4. Effect of silver nanoparticles on the spectral luminescent properties of a gelatin film

    International Nuclear Information System (INIS)

    Ehfendiev, T.Sh.; Kruchenok, Yu.V.; Rubinov, A.N.

    2013-01-01

    We studied the absorption and fluorescence spectra of a rhodamine 6G-activated gelatin film of thickness 10 μm, with and without silver nanoparticles.We observed that doping the film with nanoparticles of diameter 5 nm leads to an increase in the intensity of the absorption spectrum by a factor of 1.17 and its short-wavelength shift (~1.5 nm), while the intensity of the fluorescence spectrum increases by a factor of ~2. (author)

  5. Effect of silver nanoparticles on the spectral luminescent properties of a gelatin film

    Science.gov (United States)

    Efendiev, T. Sh.; Kruchenok, J. V.; Rubinov, A. N.

    2013-03-01

    We studied the absorption and fluorescence spectra of a rhodamine 6G-activated gelatin film of thickness 10 μm, with and without silver nanoparticles. We observed that doping the film with nanoparticles of diameter 5 nm leads to an increase in the intensity of the absorption spectrum by a factor of 1.17 and its short-wavelength shift (~1.5 nm), while the intensity of the fluorescence spectrum increases by a factor of ~2.

  6. Thermoelectric properties of conducting polyaniline/BaTiO3 nanoparticle composite films

    Science.gov (United States)

    Anno, H.; Yamaguchi, K.; Nakabayashi, T.; Kurokawa, H.; Akagi, F.; Hojo, M.; Toshima, N.

    2011-05-01

    Conducting polyaniline (PANI)/BaTiO3 nanoparticle composite films with different molar ratio values R=1, 5, 10, and 100 have been prepared on a quartz substrate by casting the m-cresol solution of PANI, (±)-10-camphorsulfonic acid (CSA) and BaTiO3 nanoparticle with an average diameter of about 20 nm. The CSA-doped PANI/BaTiO3 composite films were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and UV-Vis transmission spectroscopy. The Seebeck coefficient and the electrical conductivity of the films with different R values, together with CSA-doped PANI films, were measured in the temperature range from room temperature to ~400 K. The relation between the Seebeck coefficient and the electrical conductivity in the composite films are discussed from a comparison of them with those of CSA-doped PANI films and other PANI composite films.

  7. Chemical bath deposited PbS thin films on ZnO nanowires for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Gertman, Ronen [Dept of Chemistry, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Osherov, Anna; Golan, Yuval [Dept of Materials Engineering, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Visoly-Fisher, Iris, E-mail: irisvf@bgu.ac.il [Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede Boqer Campus 84990 (Israel)

    2014-01-01

    Photovoltaic devices usually exploit mid-range band-gap semiconductors which absorb in the visible range of the solar spectrum. However, much energy is lost in the IR and near-IR range. We combined the advantages of small band-gap, bulk-like PbS deposited by facile, cheap and direct chemical bath deposition (CBD), with the good electronic properties of ZnO and the large surface area of nanowires, towards low cost photovoltaic devices utilizing IR and near-IR light. Surprisingly, CBD of PbS on ZnO, and particularly on ZnO nanowires, was not studied hitherto. Therefore, the mechanism of PbS growth by chemical bath deposition on ZnO nanowires was studied in details. A visible proof is shown for a growth mechanism starting from amorphous Pb(OH){sub 2} layer, that evolved into the ‘ion-by-ion’ growth mechanism. The growth mechanism and the resulting morphology at low temperatures were controlled by the thiourea concentration. The grain size affected the magnitude of the band-gap and was controlled by the deposition temperatures. Deposition above 40 °C resulted in bulk-like PbS with an optical band-gap of 0.4 eV. Methods were demonstrated for achieving complete PbS coverage of the complex ZnO NW architecture, a crucial requirement in optoelectronic devices to prevent shorts. Measurements of photocurrents under white and near-IR (784 nm) illumination showed that despite a 200 meV barrier for electron transfer at the PbS/ZnO interface, extraction of photo-electrons from PbS to the ZnO was feasible. The ability to harvest electrons from a narrow band-gap semiconductor deposited on a large surface-area electrode can advance the field towards high efficiency, low cost IR and near-IR sensors and third generation solar cells. - Highlights: • PbS was deposited on ZnO nanowires using chemical bath deposition. • At 50 °C the growth mechanism starts from an amorphous Pb(OH){sub 2} layer. • At 5 °C the growth mechanism of PbS can be controlled by thiourea concentrations

  8. Laser-Induced, Local Oxidation of Copper Nanoparticle Films During Raman Measurements

    Science.gov (United States)

    Hight Walker, Angela R.; Cheng, Guangjun; Calizo, Irene

    2011-03-01

    The optical properties of gold and silver nanoparticles and their films have been thoroughly investigated as surface enhanced Raman scattering (SERS) substrates and chemical reaction promoters. Similar to gold and silver nanoparticles, copper nanoparticles exhibit distinct plasmon absorptions in the visible region. The work on copper nanoparticles and their films is limited due to their oxidization in air. However, their high reactivity actually provides an opportunity to exploit the laser-induced thermal effect and chemical reactions of these nanoparticles. Here, we present our investigation of the local oxidation of a copper nanoparticle film induced by a visible laser source during Raman spectroscopic measurements. The copper nanoparticle film is prepared by drop-casting chemically synthesized copper colloid onto silicon oxide/silicon substrate. The local oxidation induced by visible lasers in Raman spectroscopy is monitored with the distinct scattering peaks for copper oxides. Optical microscopy and scanning electron microscopy have been used to characterize the laser-induced morphological changes in the film. The results of this oxidation process with different excitation wavelengths and different laser powers will be presented.

  9. 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.

  10. Antimicrobial Activity of TiO2 Nanoparticle-Coated Film for Potential Food Packaging Applications

    Directory of Open Access Journals (Sweden)

    Siti Hajar Othman

    2014-01-01

    Full Text Available Recent uses of titanium dioxide (TiO2 have involved various applications which include the food industry. This study aims to develop TiO2 nanoparticle-coated film for potential food packaging applications due to the photocatalytic antimicrobial property of TiO2. The TiO2 nanoparticles with varying concentrations (0–0.11 g/ 100 mL organic solvent were coated on food packaging film, particularly low density polyethylene (LDPE film. The antimicrobial activity of the films was investigated by their capability to inactivate Escherichia coli (E. coli in an actual food packaging application test under various conditions, including types of light (fluorescent and ultraviolet (UV and the length of time the film was exposed to light (one–three days. The antimicrobial activity of the TiO2 nanoparticle-coated films exposed under both types of lighting was found to increase with an increase in the TiO2 nanoparticle concentration and the light exposure time. It was also found that the antimicrobial activity of the films exposed under UV light was higher than that under fluorescent light. The developed film has the potential to be used as a food packaging film that can extend the shelf life, maintain the quality, and assure the safety of food.

  11. Assembly of tantalum porous films with graded oxidation profile from size-selected nanoparticles

    Science.gov (United States)

    Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Cassidy, Cathal; Benelmekki, Maria; Bohra, Murtaza; Hawash, Zafer; Baughman, Kenneth W.; Sowwan, Mukhles

    2014-05-01

    Functionally graded materials offer a way to improve the physical and chemical properties of thin films and coatings for different applications in the nanotechnology and biomedical fields. In this work, design and assembly of nanoporous tantalum films with a graded oxidation profile perpendicular to the substrate surface are reported. These nanoporous films are composed of size-selected, amorphous tantalum nanoparticles, deposited using a gas-aggregated magnetron sputtering system, and oxidized after coalescence, as samples evolve from mono- to multi-layered structures. Molecular dynamics computer simulations shed light on atomistic mechanisms of nanoparticle coalescence, which govern the films porosity. Aberration-corrected (S) TEM, GIXRD, AFM, SEM, and XPS were employed to study the morphology, phase and oxidation profiles of the tantalum nanoparticles, and the resultant films.

  12. 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.

  13. The fabrication and characterization of inkjet-printed polyaniline nanoparticle films

    International Nuclear Information System (INIS)

    Morrin, Aoife; Ngamna, Orawan; O'Malley, Eimer; Kent, Nigel; Moulton, Simon E.; Wallace, Gordon G.; Smyth, Malcolm R.; Killard, Anthony J.

    2008-01-01

    This paper reports on the fabrication and characterization of electrodes modified with conducting polymer nanoparticle films, produced via inkjet printing. The polyaniline nanoparticle formulations were deposited via a desktop inkjet printer onto screen-printed carbon-paste electrodes (SPE), polyethylene terephthalate (PET) and gold-PET and their morphology studied at a range of length scales using profilometry, scanning electron microscopy and atomic force microscopy. The deposited films were found to form continuous polymer films depending upon film thickness, which was in turn dependent on the number of prints performed. The inkjet-printed films exhibited a smooth morphology on the SPEs at the micro-dimensional scale, as a result of the aggradation and coalescing of the nanoparticles upon deposition. The resulting modified electrodes were both conductive and electroactive, possessing good reversible polyaniline electrochemistry. Such a combination of materials and processing offers the potential of producing a range of low cost, solid state devices such as sensors, actuators and electrochromic devices

  14. Highly stable field emission from ZnO nanowire field emitters controlled by an amorphous indium–gallium–zinc-oxide thin film transistor

    Science.gov (United States)

    Li, Xiaojie; Wang, Ying; Zhang, Zhipeng; Ou, Hai; She, Juncong; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

    2018-04-01

    Lowering the driving voltage and improving the stability of nanowire field emitters are essential for them to be applied in devices. In this study the characteristics of zinc oxide (ZnO) nanowire field emitter arrays (FEAs) controlled by an amorphous indium–gallium–zinc-oxide thin film transistor (a-IGZO TFT) were studied. A low driving voltage along with stabilization of the field emission current were achieved. Modulation of field emission currents up to three orders of magnitude was achieved at a gate voltage of 0–32 V for a constant anode voltage. Additionally, a-IGZO TFT control can dramatically reduce the emission current fluctuation (i.e., from 46.11 to 1.79% at an emission current of ∼3.7 µA). Both the a-IGZO TFT and ZnO nanowire FEAs were prepared on glass substrates in our research, demonstrating the feasibility of realizing large area a-IGZO TFT-controlled ZnO nanowire FEAs.

  15. Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels.

    Science.gov (United States)

    Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

    2016-09-28

    We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

  16. Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels

    Science.gov (United States)

    Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

    2016-09-01

    We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

  17. Preparation and properties of carbohydrate-based composite films incorporated with CuO nanoparticles.

    Science.gov (United States)

    Shankar, Shiv; Wang, Long-Feng; Rhim, Jong-Whan

    2017-08-01

    The present study aimed to develop the carbohydrate biopolymer based antimicrobial films for food packaging application. The nanocomposite films of various biopolymers and copper oxide nanoparticles (CuONPs) were prepared by solvent casting method. The nanocomposite films were characterized using SEM, FTIR, XRD, and UV-vis spectroscopy. The thermal stability, UV barrier, water vapor permeability, and antibacterial activity of the composite films were also evaluated. The surface morphology of the films was dependent on the types of polymers used. The XRD revealed the crystallinity of CuONPs in the composite films. The addition of CuONPs increased the thickness, tensile strength, UV barrier property, relative humidity, and water vapor barrier property. The CuONPs incorporated composite films exhibited strong antibacterial activity against Escherichia coli and Listeria monocytogenes. The developed composite films could be used as a UV-light barrier antibacterial films for active food packaging. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Composite Films Formed by Cellulose nanocrystals and Latex Nanoparticles: Optical, Structural, and Mechanical Properties

    Science.gov (United States)

    Vollick, Brandon McRae

    This thesis describes the preparation of iridescent, birefringent, composite films composed of cellulose nanocrystals (CNCs), latex nanoparticles (NPs) and a NP crosslinker; hexanediamine (HDA). First, aqueous suspensions were prepared with varying quantities of CNCs, NPs and HDA before equilibrating for one week. The cholesteric (Ch) phase was then cast and dried into a film. The optical, structural and mechanical properties of the film was analyzed. Second, films with identical compositions of CNCs, NPs, and HDA were fabricated in three different ways to yield films of different morphology, (i) fast drying of an isotropic suspension, yielding an isotropic film, (ii) slow drying of an isotropic suspension, yielding a partially Ch films, (iii) slow drying of an equilibrated suspension, yielding a highly Ch film. The optical and mechanical properties of the films was analyzed.

  19. Magnetic nanoparticles as a seed layer for growing ZnO nanowires for optical applications

    International Nuclear Information System (INIS)

    AlSalhi, M S; Atif, M; Ansari, Anees A; Khun, K; Ibupoto, Z H; Willander, M

    2013-01-01

    In the present work, cerium oxide CeO 2 nanoparticles were synthesised by sol-gel method and used for the growth of ZnO nanorods. The synthesised nanoparticles were studied by x-ray diffraction technique [XRD]. Furthermore, these nanoparticles were used as seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by using field emission scanning electron microscopy [FESEM], and x-ray diffraction [XRD] techniques. This study demonstrated that the grown ZnO nanorods are well align, uniform, good in crystal quality and possess diameter of less than 200 nm. Energy dispersive x-rays [EDX] revealed that the ZnO nanorods are only composed of zinc, cerium as seed atom and oxygen atoms and no any other impurity in the grown nanorods. Moreover, photoluminescence [PL] approach was applied for the optical characterisation and it was observed that the near-band-edge emission [NBE] was same to that of zinc acetate seed layer, however the green emission and orange/red emission peaks were slightly raised due to possible higher level of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the synthesis of controlled ZnO nanorods using cerium oxide nanoparticles as seed nucleation layer which in reverse describe the application of these nanoparticles as well as due to controlled morphology of ZnO nanorods the performance of nanodevices based on ZnO can be increased using these particles as seed.

  20. Nanoporous Thin Film Templates for the Fabrication of Nanowires and Nanotubes

    DEFF Research Database (Denmark)

    Bordo, Kirill

    2011-01-01

    (silicon, glass, ITO-glass, mica) with the use of different electrolytes (oxalic, sulphuric and phosphoric acid) has also been systematically studied. It has been found that the structure of such films depends strongly on the structure and morphology of the initial thin Al films as well...

  1. Evaluation of antimicrobial activity of silver nanoparticles for carboxymethylcellulose film applications in food packaging.

    Science.gov (United States)

    Siqueira, Maria C; Coelho, Gustavo F; de Moura, Márcia R; Bresolin, Joana D; Hubinger, Silviane Z; Marconcini, José M; Mattoso, Luiz H C

    2014-07-01

    In this study, silver nanoparticles were prepared and incorporated into carboxymethylcellulose films to evaluate the antimicrobial activity for food packaging applications. The techniques carried out for material characterization were: infrared spectroscopy and thermal analysis for the silver nanoparticles and films, as well as particle size distribution for the nanoparticles and water vapor permeability for the films. The antimicrobial activity of silver nanoparticles prepared by casting method was investigated. The minimum inhibitory concentration (MIC) value of the silver nanoparticles to test Gram-positive (Enterococcus faecalis) and Gram-negative (Escherichia coli) microorganisms was carried out by the serial dilution technique, tested in triplicate to confirm the concentration used. The results were developed using the Mcfarland scale which indicates that the presence or absence of turbidity tube demonstrates the inhibition of bacteria in relation to the substance inoculated. It was found that the silver nanoparticles inhibited the growth of the tested microorganisms. The carboxymethylcellulose film embedded with silver nanoparticles showed the best antimicrobial effect against Gram-positive (E. faecalis) and Gram-negative (E. coli) bacteria (0.1 microg cm(-3)).

  2. Surface-enhanced Raman spectroscopy (SERS) using Ag nanoparticle films produced by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, C.A., E-mail: smythc2@tcd.ie [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Mirza, I.; Lunney, J.G.; McCabe, E.M. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Pulsed laser deposition (PLD) produces silver nanoparticle films. Black-Right-Pointing-Pointer These films can be used for surface-enhanced Raman spectroscopy (SERS). Black-Right-Pointing-Pointer Commercial film shows good SERS reproducibility but poor signal intensity. Black-Right-Pointing-Pointer PLD shows a good SERS response coupled with good reproducibility. - Abstract: Thin silver nanoparticle films, of thickness 7 nm, were deposited onto glass microslides using pulsed laser deposition (PLD). The films were then characterised using UV-vis spectroscopy and scanning transmission electron microscopy before Rhodamine 6G was deposited onto them for investigation using surface-enhanced Raman spectroscopy (SERS). The sensitivity obtained using SERS was compared to that obtained using a colloidal silver suspension and also to a commercial SERS substrate. The reproducibility of the films is also examined using statistical analysis.

  3. Convenient preparation of ITO nanoparticles inks for transparent conductive thin films

    International Nuclear Information System (INIS)

    Ito, Daisuke; Masuko, Keiichiro; Weintraub, Benjamin A.; McKenzie, Lallie C.; Hutchison, James E.

    2012-01-01

    Tin-doped indium oxide (ITO) nanoparticles are useful precursors to transparent electrodes in a variety of technologically important applications. We synthesized ITO nanoparticles from indium and tin acetylacetonates in oleyl alcohol using a novel temperature ramp profile. The monodispersed ITO nanoparticles have an average diameter of 8.6 nm and form dense, flat films by simple spin coating. The thickness of the film can be controlled by varying the number of additional depositions. The resulting ITO film is transparent and has a resistivity of 7 × 10 −3 Ω cm after sintering at 300 °C. Using a suitable solvent, it is possible to coat high-aspect-ratio structures with ITO nanoparticles. This approach to ITO coatings is greener and offers a number of advantages for transparent electrodes because it is highly versatile, easily scalable, and supports low-cost manufacturing.

  4. Hybrid composite thin films composed of tin oxide nanoparticles and cellulose

    International Nuclear Information System (INIS)

    Mahadeva, Suresha K; Nayak, Jyoti; Kim, Jaehwan

    2013-01-01

    This paper reports the preparation and characterization of hybrid thin films consisting of tin oxide (SnO 2 ) nanoparticles and cellulose. SnO 2 nanoparticle loaded cellulose hybrid thin films were fabricated by a solution blending technique, using sodium dodecyl sulfate as a dispersion agent. Scanning and transmission electron microscopy studies revealed uniform dispersion of the SnO 2 nanoparticles in the cellulose matrix. Reduction in the crystalline melting transition temperature and tensile properties of cellulose was observed due to the SnO 2 nanoparticle loading. Potential application of these hybrid thin films as low cost, flexible and biodegradable humidity sensors is examined in terms of the change in electrical resistivity of the material exposed to a wide range of humidity as well as its response–recovery behavior. (paper)

  5. Asymmetric photoelectric property of transparent TiO2 nanotube films loaded with Au nanoparticles

    International Nuclear Information System (INIS)

    Wang, Hui; Liang, Wei; Liu, Yiming; Zhang, Wanggang; Zhou, Diaoyu; Wen, Jing

    2016-01-01

    Highlights: • Highly transparent films of TiO 2 nanotube arrays were directly fabricated on FTO glasses. • Semitransparent TNT-Au composite films were obtained and exhibited excellent photoelectrocatalytic ability. • Back-side of TNT-Au composite films was firstly irradiated and tested to compare with front-side of films. - Abstract: Semitransparent composite films of Au loaded TiO 2 nanotubes (TNT-Au) were prepared by sputtering Au nanoparticles on highly transparent TiO 2 nanotubes films, which were fabricated directly on FTO glasses by anodizing the Ti film sputtered on the FTO glasses. Compared with pure TNT films, the prepared TNT-Au films possessed excellent absorption ability and high photocurrent response and improved photocatalytic activity under visible-light irradiation. It could be concluded that Au nanoparticles played important roles in improving the photoelectrochemical performance of TNT-Au films. Moreover, in this work, both sides of TNT-Au films were researched and compared owing to theirs semitransparency. It was firstly found that the photoelectric activity of TNT-Au composite films with back-side illumination was obviously superior to front-side illumination.

  6. Asymmetric photoelectric property of transparent TiO{sub 2} nanotube films loaded with Au nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); College of Applied Science, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Liang, Wei, E-mail: 986903124@qq.com [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Liu, Yiming; Zhang, Wanggang; Zhou, Diaoyu; Wen, Jing [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China)

    2016-11-15

    Highlights: • Highly transparent films of TiO{sub 2} nanotube arrays were directly fabricated on FTO glasses. • Semitransparent TNT-Au composite films were obtained and exhibited excellent photoelectrocatalytic ability. • Back-side of TNT-Au composite films was firstly irradiated and tested to compare with front-side of films. - Abstract: Semitransparent composite films of Au loaded TiO{sub 2} nanotubes (TNT-Au) were prepared by sputtering Au nanoparticles on highly transparent TiO{sub 2} nanotubes films, which were fabricated directly on FTO glasses by anodizing the Ti film sputtered on the FTO glasses. Compared with pure TNT films, the prepared TNT-Au films possessed excellent absorption ability and high photocurrent response and improved photocatalytic activity under visible-light irradiation. It could be concluded that Au nanoparticles played important roles in improving the photoelectrochemical performance of TNT-Au films. Moreover, in this work, both sides of TNT-Au films were researched and compared owing to theirs semitransparency. It was firstly found that the photoelectric activity of TNT-Au composite films with back-side illumination was obviously superior to front-side illumination.

  7. Effect of silver nanoparticles on photo-induced reorientation of azo groups in polymer films

    International Nuclear Information System (INIS)

    Zhou Jingli; Yang Jianjun; Sun Youyi; Zhang Douguo; Shen Jing; Zhang Qijin; Wang Keyi

    2007-01-01

    A series of polymer films containing azo groups and silver nanoparticles were prepared. Photo-induced reorientation of the film was conducted under irradiation of polarized light with wavelength at 365 nm, 442 nm and 532 nm, respectively. The influence of the concentration of dopant silver on the reorientation of the azo groups was studied. An enhancement of about 50% for the reorientation rate and about 70% for the reorientation amplitude was achieved. From a comparison of the enhancement obtained by irradiating with three different light sources, it was realized that the mechanism for enhancement of reorientation of azo groups is due to plasmon resonance of silver nanoparticles doped in the polymer films

  8. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  9. Controlled specific placement of nanoparticles into microdomains of block copolymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Joonwon, E-mail: joonwonbae@gmail.com [Department of Applied Chemistry, Dongduk Women' s University, Seoul 136-714 (Korea, Republic of); Kim, Jungwook [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742 (Korea, Republic of); Park, Jongnam, E-mail: jnpark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of)

    2014-07-01

    Conceptually attractive hybrid materials composed of nanoparticles and elegant block copolymers have become important for diverse applications. In this work, controlled specific placement of nanoparticles such as gold (Au) and titania (TiO{sub 2}) into microphase separated domains in poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films was demonstrated. The effect of nanoparticle surface functionality on the spatial location of particles inside polymer film was observed by transmission electron microscopy. It was revealed that the location of nanoparticles was highly dependent on the surface ligand property of nanoparticle. In addition, the microphase separation behavior of thin block copolymer film was also affected by the nanoparticle surface functional groups. This study might provide a way to understand the properties and behaviors of numerous block copolymer/nanoparticle hybrid systems. - Highlights: • Controlled location of nanoparticles in the block copolymer matrix • Tailoring surface functionality of metal nanocrystals • Fabrication of homogeneous nanocomposites using organic inorganic components • Possibility for the preparation of nanohybrids.

  10. Controlled specific placement of nanoparticles into microdomains of block copolymer thin films

    International Nuclear Information System (INIS)

    Bae, Joonwon; Kim, Jungwook; Park, Jongnam

    2014-01-01

    Conceptually attractive hybrid materials composed of nanoparticles and elegant block copolymers have become important for diverse applications. In this work, controlled specific placement of nanoparticles such as gold (Au) and titania (TiO 2 ) into microphase separated domains in poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films was demonstrated. The effect of nanoparticle surface functionality on the spatial location of particles inside polymer film was observed by transmission electron microscopy. It was revealed that the location of nanoparticles was highly dependent on the surface ligand property of nanoparticle. In addition, the microphase separation behavior of thin block copolymer film was also affected by the nanoparticle surface functional groups. This study might provide a way to understand the properties and behaviors of numerous block copolymer/nanoparticle hybrid systems. - Highlights: • Controlled location of nanoparticles in the block copolymer matrix • Tailoring surface functionality of metal nanocrystals • Fabrication of homogeneous nanocomposites using organic inorganic components • Possibility for the preparation of nanohybrids

  11. Non-monotonic wetting behavior of chitosan films induced by silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Praxedes, A.P.P.; Webler, G.D.; Souza, S.T. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Ribeiro, A.S. [Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Fonseca, E.J.S. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Oliveira, I.N. de, E-mail: italo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil)

    2016-05-01

    Highlights: • The addition of silver nanoparticles modifies the morphology of chitosan films. • Metallic nanoparticles can be used to control wetting properties of chitosan films. • The contact angle shows a non-monotonic dependence on the silver concentration. - Abstract: The present work is devoted to the study of structural and wetting properties of chitosan-based films containing silver nanoparticles. In particular, the effects of silver concentration on the morphology of chitosan films are characterized by different techniques, such as atomic force microscopy (AFM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). By means of dynamic contact angle measurements, we study the modification on surface properties of chitosan-based films due to the addition of silver nanoparticles. The results are analyzed in the light of molecular-kinetic theory which describes the wetting phenomena in terms of statistical dynamics for the displacement of liquid molecules in a solid substrate. Our results show that the wetting properties of chitosan-based films are high sensitive to the fraction of silver nanoparticles, with the equilibrium contact angle exhibiting a non-monotonic behavior.

  12. Entropy driven spontaneous formation of highly porous films from polymer-nanoparticle composites

    International Nuclear Information System (INIS)

    Korampally, Venumadhav; Yun, Minseong; Rajagopalan, Thiruvengadathan; Gangopadhyay, Keshab; Gangopadhyay, Shubhra; Dasgupta, Purnendu K

    2009-01-01

    Nanoporous materials have become indispensable in many fields ranging from photonics, catalysis and semiconductor processing to biosensor infrastructure. Rapid and energy efficient process fabrication of these materials is, however, nontrivial. In this communication, we describe a simple method for the rapid fabrication of these materials from colloidal dispersions of Polymethyl Silsesquioxane nanoparticles. Nanoparticle-polymer composites above the decomposition temperature of the polymer are examined and the entropic gain experienced by the nanoparticles in this rubric is harnessed to fabricate novel highly porous films composed of nanoparticles. Optically smooth, hydrophobic films with low refractive indices (as low as 1.048) and high surface areas (as high as 1325 m 2 g -1 ) have been achieved with this approach. In this communication we address the behavior of such systems that are both temperature and substrate surface energy dependent. The method is applicable, in principle, to a variety of nanoparticle-polymer systems to fabricate custom nanoporous materials.

  13. The immobilization of titania nanoparticles on hyaluronan films and their photocatalytic properties

    International Nuclear Information System (INIS)

    Pasqui, Daniela; Atrei, Andrea; Barbucci, Rolando

    2009-01-01

    We have developed a method to bind titania nanoparticles onto hyaluronic films (HA) photoimmobilized on silanized glass. Titania nanoparticles were deposited on the HA films from commercially available dispersions by casting and dip-coating methods at various pH values. XPS was used to monitor the deposition of titania and to estimate the surface coverage of the nanoparticles. The topography of the titania-modified HA films was investigated by means of AFM. XPS results indicate that the titania surface coverage depends on the preparation method and the pH of the dispersion. We found that the maximum titania nanoparticle surface coverage was obtained by the casting method with the formation of aggregates and multilayers of particles. The titania surface coverage for the surfaces prepared by the dip-coating method is pH-dependent. The surfaces prepared at pH 2 show a surface coverage of 65% and a rather uniform distribution of particles. We found that titania nanoparticles are anchored in a stable way to the HA substrate in a phosphate buffer solution (PBS) and that the interaction between the HA and the titania is through the carbonyl group of carboxylates and amidic groups of the polymer. AFM images clearly show that titania nanoparticles are uniformly distributed over the HA films. By measuring the average diameter and the average height of the nanoparticles deposited on HA films it appears that the particles are partially embedded in the polysaccharide films. The results of the study on the photobleaching of methylene blue indicate that the characteristic photocatalytic activity of titania is maintained when the nanoparticles are anchored to the HA substrate.

  14. 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.

  15. The influence of thin film grain size on the size of nanoparticles generated during UV femtosecond laser ablation of thin gold films

    Energy Technology Data Exchange (ETDEWEB)

    Haustrup, N., E-mail: natalie.haustrup@nuigalway.ie [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland); O’Connor, G.M. [National Centre for Laser Applications, School of Physics, National University of Ireland, Galway (Ireland)

    2013-08-01

    The upsurge in the number of thin film products has encouraged studies into every aspect of their fabrication and application. An additional source of industrial interest is the laser ablation of thin films to generate nanoparticles. This technique offers advantages over other fabrication methods, as no chemical pre-cursers are required, thereby giving rise to a pure product. The main disadvantage lies in the difficulty with controlling the size of the nanoparticles. This study aims to clarify the influence of the microstructure of a thin film on its optical properties and also to establish the size relationship between the film grain and the nanoparticles generated during laser ablation. A comprehensive sample set of Gold (Au) films with different grain sizes was achieved using different deposition rates, temperatures, film thicknesses (<100 nm) and substrates: Silica, Quartz and Sapphire. The microstructure of each film was analyzed using Atomic Force Microscopy (AFM). Single femtosecond laser pulses, above the ablation threshold fluence of each film, were applied to generate nanoparticles. Scanning Electron Microscopy (SEM) was used to image the re-deposited nanoparticles, from which the nanoparticle size distribution was established. Results confirm that the film microstructure is directly linked to the nanoparticles generated during laser ablation.

  16. The influence of thin film grain size on the size of nanoparticles generated during UV femtosecond laser ablation of thin gold films

    International Nuclear Information System (INIS)

    Haustrup, N.; O’Connor, G.M.

    2013-01-01

    The upsurge in the number of thin film products has encouraged studies into every aspect of their fabrication and application. An additional source of industrial interest is the laser ablation of thin films to generate nanoparticles. This technique offers advantages over other fabrication methods, as no chemical pre-cursers are required, thereby giving rise to a pure product. The main disadvantage lies in the difficulty with controlling the size of the nanoparticles. This study aims to clarify the influence of the microstructure of a thin film on its optical properties and also to establish the size relationship between the film grain and the nanoparticles generated during laser ablation. A comprehensive sample set of Gold (Au) films with different grain sizes was achieved using different deposition rates, temperatures, film thicknesses (<100 nm) and substrates: Silica, Quartz and Sapphire. The microstructure of each film was analyzed using Atomic Force Microscopy (AFM). Single femtosecond laser pulses, above the ablation threshold fluence of each film, were applied to generate nanoparticles. Scanning Electron Microscopy (SEM) was used to image the re-deposited nanoparticles, from which the nanoparticle size distribution was established. Results confirm that the film microstructure is directly linked to the nanoparticles generated during laser ablation.

  17. Surface properties of anatase TiO2 nanowire films grown from a fluoride-containing solution.

    Science.gov (United States)

    Berger, Thomas; Anta, Juan A; Morales-Flórez, Víctor

    2013-06-03

    Controlling the surface chemistry of nucleating seeds during wet-chemical synthesis allows for the preparation of morphologically well-defined nanostructures. Synthesis conditions play a key role in the surface properties, which directly affect the functional properties of the material. Therefore, it is important to establish post-synthesis treatments to facilitate the optimization of surface properties with respect to a specific application, without losing the morphological peculiarity of the nanostructure. We studied the surface properties of highly crystalline and porous anatase TiO2 nanowire (NW) electrodes, grown by chemical-bath deposition in fluoride-containing solutions, using a combined electrochemical and spectroscopic approach. As-deposited films showed low capacity for catechol adsorption and a poor photoelectrocatalytic activity for water oxidation. Mild thermal annealing at 200 °C resulted in a significant improvement of the electrode photoelectrocatalytic activity, whereas the bulk properties of the NWs (crystal structure, band-gap energy) remained unchanged. Enhancement of the functional properties of the material is discussed on the basis of adsorption capacity and electronic properties. The temperature-induced decrease of recombination centers, along with the concomitant increase of adsorption and reaction sites upon thermal annealing are called to be responsible for such improved performance. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Dewetting dynamics of a gold film on graphene: implications for nanoparticle formation.

    Science.gov (United States)

    Namsani, Sadanandam; Singh, Jayant K

    2016-01-01

    The dynamics of dewetting of gold films on graphene surfaces is investigated using molecular dynamics simulation. The effect of temperature (973-1533 K), film diameter (30-40 nm) and film thickness (0.5-3 nm) on the dewetting mechanism, leading to the formation of nanoparticles, is reported. The dewetting behavior for films ≤5 Å is in contrast to the behavior seen for thicker films. The retraction velocity, in the order of ∼300 m s(-1) for a 1 nm film, decreases with an increase in film thickness, whereas it increases with temperature. However at no point do nanoparticles detach from the surface within the temperature range considered in this work. We further investigated the self-assembly behavior of nanoparticles on graphene at different temperatures (673-1073 K). The process of self-assembly of gold nanoparticles is favorable at lower temperatures than at higher temperatures, based on the free-energy landscape analysis. Furthermore, the shape of an assembled structure is found to change from spherical to hexagonal, with a marked propensity towards an icosahedral structure based on the bond-orientational order parameters.

  19. From Gold Nano-particles through Nano-wire to Gold Nano-layers on Substrate

    Czech Academy of Sciences Publication Activity Database

    Švorčík, V.; Kolská, Z.; Slepička, P.; Siegel, J.; Hnatowicz, Vladimír

    2010-01-01

    Roč. 2010, G (2010), s. 1-57. ISBN 978-1-61668-009-1 Institutional support: RVO:61389005 Keywords : thin films * Au nano layers * AFM Subject RIV: BM - Solid Matter Physics ; Magnetism https://www.novapublishers.com/catalog/product_info.php?products_id=12909

  20. Design principle for absorption enhancement with nanoparticles in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    Xu, Yuanpei; Xuan, Yimin

    2015-01-01

    The use of nanoparticles in solar cells has created many controversies. In this paper, different mechanisms of nanoparticles with different materials with diameters varying from 50 to 200 nm, surface coverage at 5, 20, and 60 %, and different locations are analyzed systematically for efficient light trapping in a thin-film c-Si solar cell. Mie theory and the finite difference time domain method are used for analysis to give a design principle with nanoparticles for the solar cell application. Metals exhibit plasmonic resonances and angular scattering, while dielectrics show anti-reflection and scattering in the incident direction. A table is given to summarize the advantages and disadvantages in different conditions. The silicon absorption enhancement with nanoparticles on top is mainly in the shorter wavelengths below 700 nm, and both Al and SiO 2 nanoparticles with diameter around 100 nm show the most significant enhancement. The silicon absorption enhancement with embedded nanoparticles takes place in the longer wavelengths over 700 nm, and Ag and SiO 2 nanoparticles with larger diameter around 200 nm perform better. However, the light absorbed by Ag nanoparticles will be converted to heat and will lead to decrease in cell efficiency; hence, the choice of metallic nanoparticles in applications to solar cells should be carefully considered. The design principle proposed in this work gives a guideline by choosing reasonable parameters for the different requirements in the application of thin-film solar cells

  1. Optical Design of Textured Thin-Film CIGS Solar Cells with Nearly-Invisible Nanowire Assisted Front Contacts

    NARCIS (Netherlands)

    Deelen, J. van; Omar, A.; Barink, M.

    2017-01-01

    The conductivity of transparent front contacts can be improved by patterned metallic nanowires, albeit at the cost of optical loss. The associated optical penalty can be strongly reduced by texturization of the cell stack. Remarkably, the nanowires themselves are not textured and not covered in our

  2. A four-functional composite-hierarchical anatase TiO2 microsphere consisting of nanoparticles, nanowires and submicron ellipsoidal spheres for Dye Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Huang, Niu; Chen, Feitai; Sun, Panpan; Sun, Xiaohua; Sebo, Bobby; Zhao, Xingzhong

    2014-01-01

    Graphical abstract: - Abstract: In this paper, we prepare a composite-hierarchical microsphere (HMS) which is composed of two kinds of HMSs: one flower-like microsphere (FMS, ∼1.5 μm, containing nanoparticles and nanowires) and plentiful mesoporous submicron ellipsoidal spheres (ESs, ∼200 nm, assembled with nanoparticles) which are embedded evenly in the FMS. For comparing, pure FMS and ES are prepared, respectively. It is found that the composite-HMS possesses (a) the highest BET surface area, (b) the highest light scattering ability, (c) the fastest electron transport and the longest electron life time, and (d) light trapping ability enabled by multiple light reflection and scattering between ESs and nanowires inside each FMS*ESs particle. The energy conversion efficiency of 7.91% of the DSSC based on FMS*ESs is higher than devices based on ES and FMS (7.22% and 7.24%, respectively), which also benefits from the structural advantages of the composite-HMS compared with non-composite HMSs

  3. Magnetic Composite Thin Films of FexOy Nanoparticles and Photocrosslinked Dextran Hydrogels

    International Nuclear Information System (INIS)

    Brunsen, Annette; Utech, Stefanie; Maskos, Michael; Knoll, Wolfgang; Jonas, Ulrich

    2012-01-01

    Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP–HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By utilizing a surface layer of a photoreactive adhesion promoter on the substrates, the MNP–HG films were covalently immobilized during photocrosslinking. The high stability of the composite was documented by rinsing experiments with UV–Vis spectroscopy, while surface plasmon resonance and optical waveguide mode spectroscopy was employed to investigate the swelling behavior in dependence of the nanoparticle concentration, the particle type, and salt concentration. - Highlights: ► blending of iron oxide nanoparticles with photocrosslinkable carboxymethyldextran. ► UV irradiation of blend yields surface-attached, magnetic hydrogel films. ► film characterization by surface plasmon resonance/optical waveguide spectroscopy. ► swelling decreases with increasing nanoparticle content. ► swelling decreases with increasing NaCl salt concentration in the aqueous medium.

  4. Surface plasmon resonance caused by gold nanoparticles formed on sprayed TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Oja Acik, I., E-mail: ilona.oja@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Dolgov, L. [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Krunks, M.; Mere, A.; Mikli, V. [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Pikker, S.; Loot, A.; Sildos, I. [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia)

    2014-02-28

    Titania films covered by gold nanoparticles are prepared by combination of spray pyrolysis and spin-coating methods. Proposed combination of techniques is prospective for photovoltaic coatings with plasmonic properties. The prepared TiO{sub 2} films with Au nanoparticles demonstrate variation in size of the gold nanocrystallites from 36 to 56 nm depending on the concentration of the HAuCl{sub 4}∙ 3H{sub 2}O solution and plasmonic light extinction in the spectral range of 600–650 nm. It is shown that gold nanocrystallites enhance Raman scattering from the underlying thin TiO{sub 2} film. - Highlights: • TiO{sub 2} thin films with Au-nanoparticles were produced by chemical solution methods. • The size and shape of Au-nanoparticles are controlled by the [HAuCl{sub 4}∙ 3H{sub 2}O]. • Plasmon light extinction was tuned from 600 to 650 nm by changing [HAuCl{sub 4}∙ 3H{sub 2}O]. • Raman scattering intensity of TiO{sub 2} films is enhanced by the Au-nanoparticles.

  5. Electrophoretic Deposition of Hydroxyapatite Film Containing Re-Doped MoS₂ Nanoparticles.

    Science.gov (United States)

    Shalom, Hila; Feldman, Yishay; Rosentsveig, Rita; Pinkas, Iddo; Kaplan-Ashiri, Ifat; Moshkovich, Alexey; Perfilyev, Vladislav; Rapoport, Lev; Tenne, Reshef

    2018-02-26

    Films combining hydroxyapatite (HA) with minute amounts (ca. 1 weight %) of (rhenium doped) fullerene-like MoS₂ (IF) nanoparticles were deposited onto porous titanium substrate through electrophoretic process (EPD). The films were analyzed by scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The SEM analysis showed relatively uniform coatings of the HA + IF on the titanium substrate. Chemical composition analysis using energy dispersive X-ray spectroscopy (EDS) of the coatings revealed the presence of calcium phosphate minerals like hydroxyapatite, as a majority phase. Tribological tests were undertaken showing that the IF nanoparticles endow the HA film very low friction and wear characteristics. Such films could be of interest for various medical technologies. Means for improving the adhesion of the film to the underlying substrate and its fracture toughness, without compromising its biocompatibility are discussed at the end.

  6. Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

    International Nuclear Information System (INIS)

    Liu, Zhiming; Wang, Xuefeng; Wu, Wenjian; Li, Mei

    2015-01-01

    Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10 −9 M after being loaded with CaM proteins. (paper)

  7. Electrophoretic Deposition of Hydroxyapatite Film Containing Re-Doped MoS2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hila Shalom

    2018-02-01

    Full Text Available Films combining hydroxyapatite (HA with minute amounts (ca. 1 weight % of (rhenium doped fullerene-like MoS2 (IF nanoparticles were deposited onto porous titanium substrate through electrophoretic process (EPD. The films were analyzed by scanning electron microscopy (SEM, X-ray diffraction and Raman spectroscopy. The SEM analysis showed relatively uniform coatings of the HA + IF on the titanium substrate. Chemical composition analysis using energy dispersive X-ray spectroscopy (EDS of the coatings revealed the presence of calcium phosphate minerals like hydroxyapatite, as a majority phase. Tribological tests were undertaken showing that the IF nanoparticles endow the HA film very low friction and wear characteristics. Such films could be of interest for various medical technologies. Means for improving the adhesion of the film to the underlying substrate and its fracture toughness, without compromising its biocompatibility are discussed at the end.

  8. Synthesis of silver nanowires using hydrothermal technique for flexible transparent electrode application

    Energy Technology Data Exchange (ETDEWEB)

    Vijila, C. V. Mary; Rahman, K. K. Arsina; Parvathy, N. S.; Jayaraj, M. K., E-mail: mkj@cusat.ac.in [Nanophotonic and Optoelectronic Division, Dept. of Physics, Cochin University of Science and Technology, Kochi, Kerala (India)

    2016-05-23

    Transparent conducting films are becoming increasingly interesting because of their applications in electronics industry such as their use in solar energy applications. In this work silver nanowires were synthesized using solvothermal method by reducing silver nitrate and adding sodium chloride for assembling silver into nanowires. Absorption spectra of nanowires in the form of a dispersion in deionized water, AFM and SEM images confirm the nanowire formation. Solution of nanowire was coated over PET films to obtain transparent conducting films.

  9. Fabrication and characterization of novel antimicrobial films derived from thymol-loaded zein-sodium caseinate (SC) nanoparticles.

    Science.gov (United States)

    Li, Kang-Kang; Yin, Shou-Wei; Yang, Xiao-Quan; Tang, Chuan-He; Wei, Zi-Hao

    2012-11-21

    The objective of this research was to fabricate novel antimicrobial films based on zein colloidal nanoparticles coated with sodium caseinate (SC), an emulsifier/stabilizer. Thymol-loaded zein-SC nanoparticles were prepared using an antisolvent technique, with the average particle size and zeta potential about 200 ± 20 nm and -40 mV, respectively. Zein-SC nanoparticle-based films exhibited higher mechanical resistance and water barrier capacity than the SC films and concomitant good extensibility as compared with zein films. Thymol loadings endowed zein-SC nanoparticle-based films with antimicrobial activity against Escherichia coli and Salmonella as well as DPPH radical scavenging activity. Water vapor permeability, microstructure, mechanical, and controlled release properties of the films were evaluated. The possible relationship between some selected physical properties and microstructure were also discussed. Atomic force microscopy (AFM) analysis indicated that thymol loadings resulted in the emergence phenomena of the nanoparticles to form large particles or packed structure, consisting of clusters of nanoparticles, within the film matrix, in a thymol loading dependent manner. The appearance of large particles or an agglomerate of particles may weaken the compactness of protein network of films and thus impair the water barrier capacity, mechanical resistance, and extensibility of the films. The release kinetics of thymol from nanoparticle-based films can be described as a two-step biphasic process, that is, an initial burst effect followed by subsequent slower release, and zein-SC nanoparticles within the films matrices gave them the ability to sustain the release of thymol. In addition, a schematic illustration of the formation pathway of zein-SC nanoparticle-based films with or without thymol was proposed to illuminate the possible relationship between some selected physical properties and the microstructure of the films.

  10. The effects of Fe2O3 nanoparticles on MgB2 superconducting thin films

    International Nuclear Information System (INIS)

    Koparan, E.T.; Sidorenko, A.; Yanmaz, E.

    2013-01-01

    Full text: Since the discovery of superconductivity in binary MgB 2 compounds, extensive studies have been carried out because of its excellent properties for technological applications, such as high transition temperature (T c = 39 K), high upper critical field (H c2 ), high critical current density (J c ). Thin films are important for fundamental research as well as technological applications of any functional materials. Technological applications primarily depend on critical current density. The strong field dependence of J c for MgB 2 necessitates an enhancement in flux pinning performance in order to improve values in high magnetic fields. An effective way to improve the flux pinning is to introduce flux pinning centers into MgB 2 through a dopant having size comparable to the coherence length of MgB 2 . In this study, MgB 2 film with a thickness of about 600 nm was deposited on the MgO (100) single crystal substrate using a 'two-step' synthesis technique. Firstly, deposition of boron thin film was carried out by rf magnetron sputtering on MgO substrates and followed by a post deposition annealing at 850 degrees Celsius in magnesium vapour. In order to investigate the effect of Fe 2 O 3 nanoparticles on the structural and magnetic properties of films, MgB 2 films were coated with different concentrations of Fe 2 O 3 nanoparticles by a spin coating process. The effects of different concentrations of ferromagnetic Fe 2 O 3 nanoparticles on superconducting properties of obtained films were carried out by using structural (XRD, SEM, AFM), electrical (R-T) and magnetization (M-H, M-T and AC Susceptibility) measurements. It was calculated that anisotropic coefficient was about γ = 1.2 and coherence length of 5 nm for the uncoated film. As a result of coherence length, the appropriate diameters of Fe 2 O 3 nanoparticles were found to be 10 nm, indicating that these nanoparticles served as the pinning centers. Based on the data obtained from this study, it can be

  11. Preparation and electrochemical properties of gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films

    International Nuclear Information System (INIS)

    Yu Aimin; Zhang Xing; Zhang Haili; Han, Deyan; Knight, Allan R.

    2011-01-01

    Highlights: → Gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films were prepared via layer-by-layer self-assembly technique. → The electron transfer behaviour of the hybrid thin films were investigated using an electrochemical probe. → The resulting thin films exhibited an electrocatalytic activity towards the oxidation of nitric oxide. - Abstract: Multi-walled carbon nanotubes (MWCNT)/polyelectrolyte (PE) hybrid thin films were fabricated by alternatively depositing negatively charged MWCNT and positively charged (diallyldimethylammonium chloride) (PDDA) via layer-by-layer (LbL) assembly technique. The stepwise growth of the multilayer films of MWCNT and PDDA was characterized by UV-vis spectroscopy. Scanning electron microscopy (SEM) images indicated that the MWCNT were uniformly embedded in the film to form a network and the coverage density of MWCNT increased with layer number. Au nanoparticles (NPs) could be further adsorbed onto the film to form PE/MWCNT/Au NPs composite films. The electron transfer behaviour of multilayer films with different compositions were studied by cyclic voltammetry using [Fe(CN) 6 ] 3-/4- as an electrochemical probe. The results indicated that the incorporation of MWCNT and Au NPs not only greatly improved the electronic conductivity of pure polyelectrolyte films, but also provided excellent electrocatalytic activity towards the oxidation of nitric oxide (NO).

  12. Diazonium-derived aryl films on gold nanoparticles: evidence for a carbon-gold covalent bond.

    Science.gov (United States)

    Laurentius, Lars; Stoyanov, Stanislav R; Gusarov, Sergey; Kovalenko, Andriy; Du, Rongbing; Lopinski, Gregory P; McDermott, Mark T

    2011-05-24

    Tailoring the surface chemistry of metallic nanoparticles is generally a key step for their use in a wide range of applications. There are few examples of organic films covalently bound to metal nanoparticles. We demonstrate here that aryl films are formed on gold nanoparticles from the spontaneous reduction of diazonium salts. The structure and the bonding of the film is probed with surface-enhanced Raman scattering (SERS). Extinction spectroscopy and SERS show that a nitrobenzene film forms on gold nanoparticles from the corresponding diazonium salt. Comparison of the SERS spectrum with spectra computed from density functional theory models reveals a band characteristic of a Au-C stretch. The observation of this stretch is direct evidence of a covalent bond. A similar band is observed in high-resolution electron energy loss spectra of nitrobenzene layers on planar gold. The bonding of these types of films through a covalent interaction on gold is consistent with their enhanced stability observed in other studies. These findings provide motivation for the use of diazonium-derived films on gold and other metals in applications where high stability and/or strong adsorbate-substrate coupling are required.

  13. Preparation and antibacterial properties of hybrid-zirconia films with silver nanoparticles

    International Nuclear Information System (INIS)

    Azócar, Ignacio; Vargas, Esteban; Duran, Nicole; Arrieta, Abel; González, Evelyn

    2012-01-01

    The antimicrobial effect of incorporating silver nanoparticles (AgNps) into zirconia matrix–polyether glycol was studied. AgNps of 4–6 nm in size were synthesized using the inverse micelles method, and different doses of metallic nanoparticles were incorporated into zirconia–polyether glycol mixtures during the ageing procedure. Atomic force microscopy (AFM) of the modified hybrid film showed a homogenous distribution of 20–80 nm diameter AgNps, indicating agglomeration of these structures during film modification; such agglomerations were greater when increasing the dosage of the colloidal system. The AgNps-hybrid films showed higher antimicrobial activity against Gram-positive bacteria than for Gram-negative bacteria. Hybrid films prepared with dioctyl sodium sulfosuccinate (AOT) stabilized AgNps presented enhanced antibacterial activity compared to that obtained through the addition of a high AgNO 3 concentration (0.3 wt%). -- Graphical abstract: Atomic Force Micrographs, top and cross section view, showing silver nanoparticles embedded in a zirconia–polyether glycol hybrid film. Highlights: ► Antibacterial activity of films (zirconia–polyether glycol) modified with silver nanoparticles. ► Biofilm formation is prevented. ► High sensibility against gram positive bacteria.

  14. Preparation and antibacterial properties of hybrid-zirconia films with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Azocar, Ignacio, E-mail: manuel.azocar@usach.cl [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Vargas, Esteban [Facultad de Ingenieria, Departamento de Metalurgia, Universidad de Santiago de Chile, USACH (Chile); Duran, Nicole [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Arrieta, Abel [Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH (Chile); Gonzalez, Evelyn [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Facultad de Ingenieria, Departamento de Metalurgia, Universidad de Santiago de Chile, USACH (Chile); Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH (Chile); Departamento de Quimica Farmacologica y Toxicologica, Facultad de Ciencias Quimicas, Universidad de Chile, Sergio Livingstone Polhammer 1007, Santiago (Chile); and others

    2012-11-15

    The antimicrobial effect of incorporating silver nanoparticles (AgNps) into zirconia matrix-polyether glycol was studied. AgNps of 4-6 nm in size were synthesized using the inverse micelles method, and different doses of metallic nanoparticles were incorporated into zirconia-polyether glycol mixtures during the ageing procedure. Atomic force microscopy (AFM) of the modified hybrid film showed a homogenous distribution of 20-80 nm diameter AgNps, indicating agglomeration of these structures during film modification; such agglomerations were greater when increasing the dosage of the colloidal system. The AgNps-hybrid films showed higher antimicrobial activity against Gram-positive bacteria than for Gram-negative bacteria. Hybrid films prepared with dioctyl sodium sulfosuccinate (AOT) stabilized AgNps presented enhanced antibacterial activity compared to that obtained through the addition of a high AgNO{sub 3} concentration (0.3 wt%). -- Graphical abstract: Atomic Force Micrographs, top and cross section view, showing silver nanoparticles embedded in a zirconia-polyether glycol hybrid film. Highlights: Black-Right-Pointing-Pointer Antibacterial activity of films (zirconia-polyether glycol) modified with silver nanoparticles. Black-Right-Pointing-Pointer Biofilm formation is prevented. Black-Right-Pointing-Pointer High sensibility against gram positive bacteria.

  15. Enhanced tribological behavior of anodic films containing SiC and PTFE nanoparticles on Ti6Al4V alloy

    International Nuclear Information System (INIS)

    Li, Songmei; Zhu, Mengqi; Liu, Jianhua; Yu, Mei; Wu, Liang; Zhang, Jindan; Liang, Hongxing

    2014-01-01

    Highlights: • An environmental friendly sodium tartrate (C 4 O 6 H 4 Na 2 ) electrolyte is used. • SiC and PTFE nanoparticles reduce friction coefficient of composite films. • SiC and PTFE nanoparticles demonstrate a favorable synergistic effect on improving tribological properties of composite films. • Lubricating mechanisms of SiC and PTFE nanoparticles are discussed. - Abstract: Anodic films containing SiC and polytetrafluoroethylene (PTFE) nanoparticles were successfully fabricated on Ti6Al4V alloy by using anodic oxidation method in an environmental friendly electrolyte. The morphology, structure and composition of the films were studied with the scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the film contained a layered structure and have a surface full of petaloid bulges, which was totally different from the common anodic oxide film of the porous kind. The tribological properties of the films were investigated with dry friction tests in terms of the friction coefficient, wear rate and the morphology of worn surfaces. The results indicated that the SiC/PTFE composite film exhibited much better anti-wear and anti-friction performances than that of the SiC composite film, the PTFE composite film and the ordinary film without nanoparticles. The SiC/PTFE composite film has friction coefficient of 0.1 and wear rate of 20.133 mg/m, which was decreased respectively by 80% and 44.5% compared with that of the ordinary film. The lubricating mechanisms of the composite film containing SiC and PTFE nanoparticles were discussed. PTFE nanoparticles could lead to the formation of lubricating layer while SiC nanoparticles inside the lubricating layer turned sliding friction to rolling friction

  16. Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jingyu; Xiao, Yihan; Xu, Ting [UCB

    2017-02-20

    Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules with a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. The present studies opened a viable route to achieve designer functional composite thin films via kinetic control.

  17. Liquid phase assisted grain growth in Cu2ZnSnS4 nanoparticle thin films by alkali element incorporation

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Canulescu, Stela; Schou, Jørgen

    2018-01-01

    The effect of adding LiCl, NaCl, and KCl to Cu2ZnSnS4 (CZTS) nanoparticle thin-film samples annealed in a nitrogen and sulfur atmosphere is reported. We demonstrate that the organic ligand-free nanoparticles previously developed can be used to produce an absorber layer of high quality. The films...

  18. High resolution selective multilayer laser processing by nanosecond laser ablation of metal nanoparticle films

    International Nuclear Information System (INIS)

    Ko, Seung H.; Pan Heng; Hwang, David J.; Chung, Jaewon; Ryu, Sangil; Grigoropoulos, Costas P.; Poulikakos, Dimos

    2007-01-01

    Ablation of gold nanoparticle films on polymer was explored using a nanosecond pulsed laser, with the goal to achieve feature size reduction and functionality not amenable with inkjet printing. The ablation threshold fluence for the unsintered nanoparticle deposit was at least ten times lower than the reported threshold for the bulk film. This could be explained by the combined effects of melting temperature depression, lower conductive heat transfer loss, strong absorption of the incident laser beam, and the relatively weak bonding between nanoparticles. The ablation physics were verified by the nanoparticle sintering characterization, ablation threshold measurement, time resolved ablation plume shadowgraphs, analysis of ablation ejecta, and the measurement and calculation of optical properties. High resolution and clean feature fabrication with small energy and selective multilayer processing are demonstrated

  19. Self-Powered Solar-Blind Photodetector with Fast Response Based on Au/β-Ga2O3 Nanowires Array Film Schottky Junction.

    Science.gov (United States)

    Chen, Xing; Liu, Kewei; Zhang, Zhenzhong; Wang, Chunrui; Li, Binghui; Zhao, Haifeng; Zhao, Dongxu; Shen, Dezhen

    2016-02-17

    Because of the direct band gap of 4.9 eV, β-Ga2O3 has been considered as an ideal material for solar-blind photodetection without any bandgap tuning. Practical applications of the photodetectors require fast response speed, high signal-to-noise ratio, low energy consumption and low fabrication cost. Unfortunately, most reported β-Ga2O3-based photodetectors usually possess a relatively long response time. In addition, the β-Ga2O3 photodetectors based on bulk, the individual 1D nanostructure, and the film often suffer from the high cost, the low repeatability, and the relatively large dark current, respectively. In this paper, a Au/β-Ga2O3 nanowires array film vertical Schottky photodiode is successfully fabricated by a simple thermal partial oxidation process. The device exhibits a very low dark current of 10 pA at -30 V with a sharp cutoff at 270 nm. More interestingly, the 90-10% decay time of our device is only around 64 μs, which is much quicker than any other previously reported β-Ga2O3-based photodetectors. Besides, the self-powering, the excellent stability and the good reproducibility of Au/β-Ga2O3 nanowires array film photodetector are helpful to its commercialization and practical applications.

  20. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    KAUST Repository

    Kim, Jin Young; Adinolfi, Valerio; Sutherland, Brandon R; Voznyy, Oleksandr; Kwon, S Joon; Kim, Tae Wu; Kim, Jeongho; Ihee, Hyotcherl; Kemp, Kyle; Adachi, Michael; Yuan, Mingjian; Kramer, Illan; Zhitomirsky, David; Hoogland, Sjoerd; Sargent, Edward H

    2015-01-01

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

  1. Improved performance of silicon-nanoparticle film-coated dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ravindra Kumar; Bedja, Idriss M. [CRC, Department of Optometry, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433 (Saudi Arabia); Aldwayyan, Abdullah Saleh [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

    2012-11-15

    Silicon (Si) nanoparticles with average size of 13 nm and orange-red luminescence under UV absorption were synthesized using electrochemical etching of silicon wafers. A film of Si nanoparticles with thickness of 0.75 {mu}m to 2.6 {mu}m was coated on the glass (TiO{sub 2} side) of a dye-sensitized solar cell (DSSC). The cell exhibited nearly 9% enhancement in power conversion efficiency ({eta}) at film thickness of {proportional_to}2.4 {mu}m under solar irradiation of 100 mW/cm{sup 2} (AM 1.5) with improved fill factor and short-circuit current density. This study revealed for the first time that the Si-nanoparticle film converting UV into visible light and helping in homogeneous irradiation, can be utilized for improving the efficiency of the DSSCs. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Electrostatically self-assembled films containing II-VI semiconductor nanoparticles: Optical and electrical properties

    International Nuclear Information System (INIS)

    Suryajaya; Nabok, A.V.; Tsargorodskaya, A.; Hassan, A.K.; Davis, F.

    2008-01-01

    CdS and ZnS semiconducting colloid nanoparticles were deposited as thin films using the technique of electrostatic self-assembly. The process of alternative deposition of Poly-allylamine Hydrochloride (PAH) and CdS (or ZnS) layers were monitored with a novel optical method of total internal reflection ellipsometry (TIRE). The fitting of TIRE spectra allowed the evaluation of the parameter (thickness, refractive index and extinction coefficients) of all consecutively deposited layers. I-V characteristics of the films obtained were studied in sandwich structures on Indium Tin Oxide (ITO) conductive electrodes using the mercury probe technique. The presence of CdS (or ZnS) nanoparticles in the polyelectrolyte films leads to a switching behaviour, which may be attributed to the resonance electron tunneling via semiconducting nanoparticles

  3. XRD total scattering of the CZTS nanoparticle absorber layer for the thin film solar cells

    DEFF Research Database (Denmark)

    Symonowicz, Joanna; Jensen, Kirsten M. Ø.; Engberg, Sara Lena Josefin

    Cu2ZnSnS4 (CZTS) thin film solar cells are cheap, non-toxic and present an efficiency up to 9,2% [1]. They can be easily manufactured by the deposition of the nanoparticle ink as a thin film followed by a thermal treatment to obtain large grains [2]. Therefore, CZTS has the potential...... to revolutionize the solar energy market. However, to commercialize CZTS nanoparticle thin films, the efficiency issues must yet be resolved. In order to do so, it is vital to understand in detail their nanoscale atomic structure. CZTS crystallize in the kesterite structure, where Cu and Zn is distributed between......-ray Diffraction data with X-ray total scattering with Pair Distribution Function analysis. Powder neutron diffraction will furthermore allow characterization of the cation disorder on the metal sites in the kesterite structure. The nanoparticle ink is also characterized by XRD, EDS, and Raman spectroscopy...

  4. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    KAUST Repository

    Kim, Jin Young

    2015-07-13

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

  5. Physical modeling and characterization of thermo-acoustic loudspeakers made of silver nano-wire films

    Science.gov (United States)

    La Torraca, P.; Larcher, L.; Bobinger, M.; Pavan, P.; Seeber, B.; Lugli, P.

    2017-06-01

    Recent developments of ultra-low heat capacity nanostructured materials revived the interest in the thermo-acoustic (TA) loudspeaker technology, which shows important advantages compared to the classical dynamic loudspeakers as they feature a lower cost and weight, flexibility, conformability to the surface of various shapes, and transparency. The development of the TA loudspeaker technology requires accurate physical models connecting the material properties to the thermal and acoustic speaker's performance. We present here a combined theoretical and experimental analysis of TA loudspeakers, where the electro-thermal and the thermo-acoustic transductions are handled separately, thus allowing an in-depth description of both the pressure and temperature dynamics. The electro-thermal transduction is analyzed by accounting for all the heat flow processes taking place between the TA loudspeaker and the surrounding environment, with focus on their frequency dependence. The thermo-acoustic conversion is studied by solving the coupled thermo-acoustic equations, derived from the Navier-Stokes equations, and by exploiting the Huygens-Fresnel principle to decompose the TA loudspeaker surface into a dense set of TA point sources. A general formulation of the 3D pressure field is derived summing up the TA point source contributions via a Rayleigh integral. The model is validated against temperature and sound pressure level measured on the TA loudspeaker sample made of a Silver Nanowire random network deposited on a polyimide substrate. A good agreement is found between measurements and simulations, demonstrating that the model is capable of connecting material properties to the thermo-acoustic performance of the device, thus providing a valuable tool for the design and optimization of TA loudspeakers.

  6. 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.

  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. The disclosed transformation of pre-sputtered Ti films into nanoparticles via controlled thermal oxidation

    Science.gov (United States)

    Awad, M. A.; Raaif, M.

    2018-05-01

    Nanoparticles of TiO2 were successfully prepared from pre-sputtered Ti films using the controlled thermal oxidation. The effect of oxidation temperature on structural, morphological and optical properties in addition to photocatalysis activity of the sputtered films was tested and explained. Analysis of XRD and EDAX elucidated the enhancement in crystallization and oxygen content with the increase of oxidation temperature. SEM depicted the formation of very fine nanoparticles with no specific border on the films oxidized at 550 and 600 °C, whilst crystallites with larger size of approximately from 16 to 23 nm have been observed for the film oxidized at 650 °C. Both optical transmission and refractive index were increased with increasing the oxidation temperature. A red shift in the absorption edge was obtained for the films oxidized at 650 °C compared to that oxidized at 600 °C. The photocatalysis tests demonstrated the priority of 600 °C nanoparticle films to decompose methyl orange (MO) more than 650 °C treated film.

  9. Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

    Science.gov (United States)

    Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

    2017-04-01

    The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Influence of Heat Treatment on the Morphologies of Copper Nanoparticles Based Films by a Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2017-01-01

    Full Text Available We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices.

  11. MAPLE deposition and characterization of SnO2 colloidal nanoparticle thin films

    International Nuclear Information System (INIS)

    Caricato, A P; Martino, M; Romano, F; Tunno, T; Valerini, D; Epifani, M; Rella, R; Taurino, A

    2009-01-01

    In this paper we report on the deposition and characterization of tin oxide (SnO 2 ) nanoparticle thin films. The films were deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. SnO 2 colloidal nanoparticles with a trioctylphosphine capping layer were diluted in toluene with a concentration of 0.2 wt% and frozen at liquid nitrogen temperature. The frozen target was irradiated with a KrF (248 nm, τ = 20 ns) excimer laser (6000 pulses at 10 Hz). The nanoparticles were deposited on silica (SiO 2 ) and (1 0 0) Si substrates and submitted to morphological (high resolution scanning electron microscopy (SEM)), structural Fourier transform infrared spectroscopy (FTIR) and optical (UV-Vis transmission) characterizations. SEM and FTIR analyses showed that trioctylphosphine was the main component in the as-deposited films. The trioctylphosphine was removed after an annealing in vacuum at 400 0 C, thus allowing to get uniform SnO 2 nanoparticle films in which the starting nanoparticle dimensions were preserved. The energy gap value, determined by optical characterizations, was 4.2 eV, higher than the bulk SnO 2 energy gap (3.6 eV), due to quantum confinement effects.

  12. Structural studies of thin films of semiconducting nanoparticles in polymer matrices

    International Nuclear Information System (INIS)

    Di Luccio, Tiziana; Piscopiello, Emanuela; Laera, Anna Maria; Antisari, Marco Vittori

    2007-01-01

    Ordered films of nanoscale materials are issue of wide interest for applications in several fields, such as optics, catalysis, and bioelectronics. In particular, semiconducting nanoparticles incorporation in a processable polymer film is an easy way to manipulate such materials for their application. We deposited thin layers of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between 200 and 300 deg. C depending on the desired size. The precursor/polymer solutions were spin-coated in order to get thin films. The spinning conditions were changed in order to optimise the layer thickness and uniformity. The samples were mainly characterised by X-ray reflectivity (XRR) and by high-resolution transmission electron microscopy (HRTEM) analyses. The thinnest layer we have deposited is 8 nm thick, as evaluated by XRR. The HRTEM measurements showed that the nanoparticles have quasi-spherical shape without evident microstructural defects. The size of the nanoparticles depends on the annealing temperature, e.g. at 232 deg. C the size of the CdS nanoparticles is about 4-5 nm

  13. Simulation study of depositing the carbon film on nanoparticles in the magnetized methane plasma

    Science.gov (United States)

    Mohammadzadeh, Hosein; Pourali, Nima; Ebadi, Zahra

    2018-03-01

    Plasma coating of nanoparticles in low-temperature magnetized methane plasma is studied by a simulation approach. To this end, by using the global model, the electron temperature and concentration of different species considered in this plasma are determined in the center of a capacitively coupled discharge. Then, the plasma-wall transition region in the presence of an oblique magnetic field is simulated by the multi-component fluid description. Nanoparticles with different radii are injected into the transition region and surface deposition and heating models, as well as dynamics and charging models, are employed to examine the coating process. The results of the simulation show that the non-spherical growth of nanoparticles is affected by the presence of the magnetic field, as with passing time, an oscillating increase is seen in the thickness of the film deposited on nanoparticles. Also, it is shown that the uniformity of the deposited film is dependent on the rotation velocity of nanoparticles. Generally, the obtained results imply that the sphericity of nanoparticles and uniformity of the film coated on them are controllable by the magnitude and orientation of the magnetic field.

  14. Structural studies of thin films of semiconducting nanoparticles in polymer matrices

    Energy Technology Data Exchange (ETDEWEB)

    Di Luccio, Tiziana [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy)], E-mail: tiziana.diluccio@portici.enea.it; Piscopiello, Emanuela; Laera, Anna Maria [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy); Antisari, Marco Vittori [ENEA, Centro Ricerche Casaccia, Via Anguillarese 301, I-00060 S. Maria di Galeria (Roma) (Italy)

    2007-09-15

    Ordered films of nanoscale materials are issue of wide interest for applications in several fields, such as optics, catalysis, and bioelectronics. In particular, semiconducting nanoparticles incorporation in a processable polymer film is an easy way to manipulate such materials for their application. We deposited thin layers of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between 200 and 300 deg. C depending on the desired size. The precursor/polymer solutions were spin-coated in order to get thin films. The spinning conditions were changed in order to optimise the layer thickness and uniformity. The samples were mainly characterised by X-ray reflectivity (XRR) and by high-resolution transmission electron microscopy (HRTEM) analyses. The thinnest layer we have deposited is 8 nm thick, as evaluated by XRR. The HRTEM measurements showed that the nanoparticles have quasi-spherical shape without evident microstructural defects. The size of the nanoparticles depends on the annealing temperature, e.g. at 232 deg. C the size of the CdS nanoparticles is about 4-5 nm.

  15. Biodegradable Starch/Copolyesters Film Reinforced with Silica Nanoparticles: Preparation and Characterization

    Science.gov (United States)

    Lima, Roberta A.; Oliveira, Rene R.; Wataya, Célio H.; Moura, Esperidiana A. B.

    Biodegradable starch/copolyesters/silica nanocomposite films were prepared by melt extrusion, using a twin screw extruder machine and blown extrusion process. The influence of the silica nanoparticle addition on mechanical and thermal properties of nanocomposite films was investigated by tensile tests; X-rays diffraction (XRD), differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM) analysis and the correlation between properties was discussed. The results showed that incorporation of 2 % (wt %) of SiO2 nanoparticle in the blend matrix of PBAT/Starch, resulted in a gain of mechanical properties of blend.

  16. Flexible Nb2O5 nanowires/graphene film electrode for high-performance hybrid Li-ion supercapacitors

    Science.gov (United States)

    Song, Hao; Fu, Jijiang; Ding, Kang; Huang, Chao; Wu, Kai; Zhang, Xuming; Gao, Biao; Huo, Kaifu; Peng, Xiang; Chu, Paul K.

    2016-10-01

    The hybrid Li-ion electrochemical supercapacitor (Li-HSC) combining the battery-like anode with capacitive cathode is a promising energy storage device boasting large energy and power densities. Orthorhombic Nb2O5 is a good anode material in Li-HSCs because of its large pseudocapacitive Li-ion intercalation capacity. Herein, we report a high-performance, binder-free and flexible anode consisting of long Nb2O5 nanowires and graphene (L-Nb2O5 NWs/rGO). The paper-like L-Nb2O5 NWs/rGO film electrode has a large mass loading of Nb2O5 of 93.5 wt% as well as short solid-state ion diffusion length, and enhanced conductivity (5.1 S cm-1). The hybrid L-Nb2O5 NWs/rGO paper electrode shows a high reversible specific capacity of 160 mA h g-1 at a current density of 0.2 A g-1, superior rate capability with capacitance retention of 60% when the current density increases from 0.2 to 5 A g-1, as well as excellent cycle stability. The Li-HSC device based on the L-Nb2O5/rGO anode and the cathode of biomass-derived carbon nanosheets delivers an energy density of 106 Wh kg-1 at 580 W kg-1 and 32 Wh kg-1 at a large power density of 14 kW kg-1. Moreover, the Li-HSC device exhibits excellent cycling performance without obvious capacitance decay after 1000 cycles.

  17. Novel Flexible Transparent Conductive Films with Enhanced Chemical and Electromechanical Sustainability: TiO2 Nanosheet-Ag Nanowire Hybrid.

    Science.gov (United States)

    Sohn, Hiesang; Kim, Seyun; Shin, Weonho; Lee, Jong Min; Lee, Hyangsook; Yun, Dong-Jin; Moon, Kyoung-Seok; Han, In Taek; Kwak, Chan; Hwang, Seong-Ju

    2018-01-24

    Flexible transparent conductive films (TCFs) of TiO 2 nanosheet (TiO 2 NS) and silver nanowire (Ag NW) network hybrid were prepared through a simple and scalable solution-based process. The as-formed TiO 2 NS-Ag NW hybrid TCF shows a high optical transmittance (TT: 97% (90.2% including plastic substrate)) and low sheet resistance (R s : 40 Ω/sq). In addition, the TiO 2 NS-Ag NW hybrid TCF exhibits a long-time chemical/aging and electromechanical stability. As for the chemical/aging stability, the hybrid TCF of Ag NW and TiO 2 NS reveals a retained initial conductivity (ΔR s /R s 4000%) or RuO 2 NS-Ag NW hybrid (ΔR s /R s > 200%). As corroborated by the density functional theory simulation, the superb chemical stability of TiO 2 NS-Ag NW hybrid is attributable to the unique role of TiO 2 NS as a barrier, which prevents Ag NW's chemical corrosion via the attenuated adsorption of sulfidation molecules (H 2 S) on TiO 2 NS. With respect to the electromechanical stability, in contrast to Ag NWs (ΔR/R 0 ∼ 152.9%), our hybrid TCF shows a limited increment of fractional resistivity (ΔR/R 0 ∼ 14.4%) after 200 000 cycles of the 1R bending test (strain: 6.7%) owing to mechanically welded Ag NW networks by TiO 2 NS. Overall, our unique hybrid of TiO 2 NS and Ag NW exhibits excellent electrical/optical properties and reliable chemical/electromechanical stabilities.

  18. Kinetic Monte Carlo simulation of nanoparticle film formation via nanocolloid drying

    Science.gov (United States)

    Kameya, Yuki

    2017-06-01

    A kinetic Monte Carlo simulation of nanoparticle film formation via nanocolloid drying is presented. The proposed two-dimensional model addresses the dynamics of nanoparticles in the vertical plane of a drying nanocolloid film. The gas-liquid interface movement due to solvent evaporation was controlled by a time-dependent chemical potential, and the resultant particle dynamics including Brownian diffusion and aggregate growth were calculated. Simulations were performed at various Peclet numbers defined based on the rate ratio of solvent evaporation and nanoparticle diffusion. At high Peclet numbers, nanoparticles accumulated at the top layer of the liquid film and eventually formed a skin layer, causing the formation of a particulate film with a densely packed structure. At low Peclet numbers, enhanced particle diffusion led to significant particle aggregation in the bulk colloid, and the resulting film structure became highly porous. The simulated results showed some typical characteristics of a drying nanocolloid that had been reported experimentally. Finally, the potential of the model as well as the remaining challenges are discussed.

  19. Modification of polypyrrole nanowires array with platinum nanoparticles and glucose oxidase for fabrication of a novel glucose biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Xu Guangqing [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia); School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Adeloju, Samuel B., E-mail: Sam.Adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia); Wu Yucheng [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zhang Xinyi [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia)

    2012-11-28

    Highlights: Black-Right-Pointing-Pointer Fabrication of well aligned PPyNWA of 20 nm diameter within AAO template. Black-Right-Pointing-Pointer Improvement of electrochemical properties by decoration with PtNPs. Black-Right-Pointing-Pointer Sensitive amperometric and potentiometric detection of glucose by adsorption of GOx on PPyNWA-PtNPs. Black-Right-Pointing-Pointer Detection of as little as 5.6 {mu}M glucose with potentiometric detection. Black-Right-Pointing-Pointer Comparable or better detection limit and sensitivity than some glucose biosensors fabricated with nanomaterials. - Abstract: A novel glucose biosensor, based on the modification of well-aligned polypyrrole nanowires array (PPyNWA) with Pt nanoparticles (PtNPs) and subsequent surface adsorption of glucose oxidase (GOx), is described. The distinct differences in the electrochemical properties of PPyNWA-GOx, PPyNWA-PtNPs, and PPyNWA-PtNPs-GOx electrodes were revealed by cyclic voltammetry. In particular, the results obtained for PPyNWA-PtNPs-GOx biosensor showed evidence of direct electron transfer due mainly to modification with PtNPs. Optimum fabrication of the PPyNWA-PtNPs-GOx biosensor for both potentiometric and amperometric detection of glucose were achieved with 0.2 M pyrrole, applied current density of 0.1 mA cm{sup -2}, polymerization time of 600 s, cyclic deposition of PtNPs from -200 mV to 200 mV, scan rate of 50 mV s{sup -1}, and 20 cycles. A sensitivity of 40.5 mV/decade and a linear range of 10 {mu}M to 1000 {mu}M (R{sup 2} = 0.9936) were achieved for potentiometric detection, while for amperometric detection a sensitivity of 34.7 {mu}A cm{sup -2} mM{sup -1} at an applied potential of 700 mV and a linear range of 0.1-9 mM (R{sup 2} = 0.9977) were achieved. In terms of achievable detection limit, potentiometric detection achieved 5.6 {mu}M of glucose, while amperometric detection achieved 27.7 {mu}M.

  20. Modification of polypyrrole nanowires array with platinum nanoparticles and glucose oxidase for fabrication of a novel glucose biosensor

    International Nuclear Information System (INIS)

    Xu Guangqing; Adeloju, Samuel B.; Wu Yucheng; Zhang Xinyi

    2012-01-01

    Highlights: ► Fabrication of well aligned PPyNWA of 20 nm diameter within AAO template. ► Improvement of electrochemical properties by decoration with PtNPs. ► Sensitive amperometric and potentiometric detection of glucose by adsorption of GOx on PPyNWA–PtNPs. ► Detection of as little as 5.6 μM glucose with potentiometric detection. ► Comparable or better detection limit and sensitivity than some glucose biosensors fabricated with nanomaterials. - Abstract: A novel glucose biosensor, based on the modification of well-aligned polypyrrole nanowires array (PPyNWA) with Pt nanoparticles (PtNPs) and subsequent surface adsorption of glucose oxidase (GOx), is described. The distinct differences in the electrochemical properties of PPyNWA–GOx, PPyNWA–PtNPs, and PPyNWA–PtNPs–GOx electrodes were revealed by cyclic voltammetry. In particular, the results obtained for PPyNWA–PtNPs–GOx biosensor showed evidence of direct electron transfer due mainly to modification with PtNPs. Optimum fabrication of the PPyNWA–PtNPs–GOx biosensor for both potentiometric and amperometric detection of glucose were achieved with 0.2 M pyrrole, applied current density of 0.1 mA cm −2 , polymerization time of 600 s, cyclic deposition of PtNPs from −200 mV to 200 mV, scan rate of 50 mV s −1 , and 20 cycles. A sensitivity of 40.5 mV/decade and a linear range of 10 μM to 1000 μM (R 2 = 0.9936) were achieved for potentiometric detection, while for amperometric detection a sensitivity of 34.7 μA cm −2 mM −1 at an applied potential of 700 mV and a linear range of 0.1–9 mM (R 2 = 0.9977) were achieved. In terms of achievable detection limit, potentiometric detection achieved 5.6 μM of glucose, while amperometric detection achieved 27.7 μM.

  1. Vertically aligned ZnO nanowire arrays in Rose Bengal-based dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Basudev; Batabyal, Sudip K.; Pal, Amlan J. [Indian Association for the Cultivation of Science, Department of Solid State Physics, Kolkata 700032 (India)

    2007-05-23

    We fabricate dye-sensitized solar cells (DSSC) using vertically oriented, high density, and crystalline array of ZnO nanowires, which can be a suitable alternative to titanium dioxide nanoparticle films. The vertical nanowires provide fast routes or channels for electron transport to the substrate electrode. As an alternative to conventional ruthenium complex, we introduce Rose Bengal dye, which acts as a photosensitizer in the dye-sensitized solar cells. The dye energetically matches the ZnO with usual KI-I{sub 2} redox couple for dye-sensitized solar cell applications. (author)

  2. Laser-induced atomic assembling of periodic layered nanostructures of silver nanoparticles in fluoro-polymer film matrix

    International Nuclear Information System (INIS)

    Bagratashvili, V N; Minaev, N V; Timashev, P S; Yusupov, V I; Rybaltovsky, A O; Firsov, V V

    2010-01-01

    Fluorinated acrylic polymer (FAP) films have been impregnated with silver precursor (Ag(hfac)COD) by supercritical fluid technique and next irradiated with laser (λ = 532 nm). Laser-chemically reduced Ag atoms have been assembled into massifs of Ag nanoparticles (3 – 8 nm) in FAP/Ag(hfac)COD films matrix in the form of periodic layered nanostructures (horizontal to film surface) with unexpectedly short period (90 – 180 nm). The wavelet analysis of TEM images reveals the existence of even shorter-period structures in such films. Photolysis with non-coherent light or pyrolysis of FAP/Ag(hfac)COD film results in formation of Ag nanoparticles massifs but free of any periodic nanoparticle assemblies. Our interpretation of the observed effect of laser formation of short-period nano-sized Ag nanoparticle assemblies is based on self-enhanced interference process in the course of modification of optical properties of film

  3. Gold-coated iron nanoparticles in transparent Si3N4 matrix thin films

    Science.gov (United States)

    Sánchez-Marcos, J.; Céspedes, E.; Jiménez-Villacorta, F.; Muñoz-Martín, A.; Prieto, C.

    2013-06-01

    A new method to prepare thin films containing gold-coated iron nanoparticles is presented. The ternary Fe-Au-Si3N4 system prepared by sequential sputtering has revealed a progressive variation of microstructures from Au/Fe/Au/Si3N4 multilayers to iron nanoparticles. Microstructural characterization by transmission electron microscopy, analysis of the magnetic properties and probing of the iron short-range order by X-ray absorption spectroscopy confirm the existence of a gold-coated iron nanoparticles of 1-2 nm typical size for a specific range of iron and gold contents per layer in the transparent silicon nitride ceramic matrix.

  4. 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.

  5. Noble metals nanoparticles on titanium dioxide nanostructured films and the influence of their photocatalytic activity

    International Nuclear Information System (INIS)

    Nakamura, Liana Key Okada

    2012-01-01

    Currently, nanoscience and nanotechnology are considered an emerging field and continuously breaking the barrier among various disciplines. The main focus of study involves controlling structures at molecular level, arranging the atoms in order to achieve an understanding and controlling the fundamental properties of matter. In this study, molecular changes on the basis of morphology, optical and crystalline properties of TiO 2 hin films in order to increase their photon efficiency were proposed. The TiO 2 thin films were prepared by sol gel process evaluating the influence of different acids and templates to obtain the nano structured arrangements. Then, metal nanoparticles like Au, Ag, Pd and Pt were incorporated on TiO 2 thin films. This incorporation might minimize the electron-hole recombination, so it could improve the photon efficiency. From the several routes studied, the TiO 2 thin films prepared with acetic acid showed the best performance by the reason of low agglomeration of TiO 2 grains, which favors the exposure of the photoactive sites. The presence of template in the formulation had a slightly effect on photon efficiency, possible due to the higher agglomeration of the grains on the TiO 2 thin films. The addition of Pt and Au nanoparticles on TiO 2 thin films showed superior photon efficiency. The TiO 2 thin films with hexamine and metallic nanoparticles did not show the improvement on photon efficiency except for Pt and Au nanoparticles. On these situations, the improvement on photon efficiency is might be due to a possible decrease at the electron-hole recombination's velocity. Thus, the present work demonstrates the great influence of preparation conditions on the optical, morphological properties and the photon efficiency. In the future, with greater understanding of the mechanism of this influence, the properties of TiO 2 thin films will be able tailoring depending on the application. (author)

  6. Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

    Directory of Open Access Journals (Sweden)

    Luiza A. Mercante

    2015-01-01

    Full Text Available The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride (Au@PAH NPs, as well as the capability of this material to form multilayer Layer-by-Layer (LbL nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc. Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM, and Fourier transform infrared spectroscopy (FTIR. Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA, revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

  7. Addition of silica nanoparticles to tailor the mechanical properties of nanofibrillated cellulose thin films.

    Science.gov (United States)

    Eita, Mohamed; Arwin, Hans; Granberg, Hjalmar; Wågberg, Lars

    2011-11-15

    Over the last decade, the use of nanocellulose in advanced technological applications has been promoted both due the excellent properties of this material in combination with its renewability. In this study, multilayered thin films composed of nanofibrillated cellulose (NFC), polyvinyl amine (PVAm) and silica nanoparticles were fabricated on polydimethylsiloxane (PDMS) using a layer-by-layer adsorption technique. The multilayer build-up was followed in situ by quartz crystal microbalance with dissipation, which indicated that the PVAm-SiO(2)-PVAm-NFC system adsorbs twice as much wet mass material compared to the PVAm-NFC system for the same number of bilayers. This is accompanied with a higher viscoelasticity for the PVAm-SiO(2)-PVAm-NFC system. Ellipsometry indicated a dry-state thickness of 2.2 and 3.4 nm per bilayer for the PVAm-NFC system and the PVAm-SiO(2)-PVAm-NFC system, respectively. Atomic force microscopy height images indicate that in both systems, a porous network structure is achieved. Young's modulus of these thin films was determined by the Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) technique. The Young's modulus of the PVAm/NFC films was doubled, from 1 to 2 GPa, upon incorporation of silica nanoparticles in the films. The introduction of the silica nanoparticles lowered the refractive index of the films, most probably due to an increased porosity of the films. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Enhanced electrochromic coloration in Ag nanoparticle decorated WO3 thin films

    International Nuclear Information System (INIS)

    Kharade, Rohini R.; Mali, Sawanta S.; Patil, Satish P.; Patil, Kashinath R.; Gang, Myong G.; Patil, Pramod S.; Kim, Jin H.; Bhosale, Popatrao N.

    2013-01-01

    Highlights: • Electrochromic WO 3 /Ag nanocomposites prepared by hybrid physico-chemical route. • XRD and XPS results confirm formation of Ag 8 W 4 O 16 phase. • WO 3 /Ag thin films showed good optical transmittance change and coloration efficiency. • SPR enhanced coloration and bleaching mechanism is well explained for electrochromism. • Color stimuli are quantified using CIE chromaticity principles. -- Abstract: WO 3 /Ag composite thin films were prepared by microwave assisted sol–gel synthesis (MW-SGS) of WO 3 followed by vacuum evaporation of Ag nanoparticles and their enhanced electrochromic coloration was investigated. The composition and morphology of WO 3 thin films with different thickness of Ag layer obtained by vacuum evaporation were investigated. Distinct plasmon absorption bands of Ag nanoparticle thin films were obtained. The optical band gap energy of WO 3 /Ag films decreased with increasing the Ag layer thickness. The surface of these films has been examined using X-ray photoelectron spectroscopy (XPS) to gain information about the chemical states of species present at surfaces. Experimental results indicated that the conductivity of the films increased after surface modification by Ag layer. To investigate the origin of enhanced electrochromic absorption in optical properties, working electrode consisting of WO 3 /Ag thin film was used and observed the optical properties during electrochemical reaction. It was found that composite electrode shows enhancement in electrochromic properties in terms of optical modulation (ΔOD) and coloration efficiency (η)

  9. Investigation of physicochemical and microbiological characteristics of prepared films containing nanoparticles of titanium oxide based on soy flour polysaccharide

    Directory of Open Access Journals (Sweden)

    D Salarbashi

    2016-11-01

    Full Text Available Introduction: The natural derived biopolymers are highly interested in recent years. These polymers are considering as the alternative for un-biodegradable plastic films. This is due to the low cost and their availability from biodegradable and renewable sources. In this study, the effect of different concentrations of Tio2 nanoparticles on physicochemical and microbiological characteristics of prepared edible films based on soy flour soluble polysaccharide was investigated. MethodS: The nanocomposite films were prepared by adding the Tio2 nanoparticles (5, 10 and 15%/ db to the soy flour. In order to investigate the physicochemical and microbiological properties, the resulted nanocomposite films were synthetized based on the casting method. Results: When the content of nanoparticles increased, the moisture content and solubility of the film specimens were significantly decreased, whereas the mechanical resistance was significantly increased. Tio2 nanoparticle was highly effective against basillus cereus, staphylococus ureus and staphylococuss epidermidis. Meanwhile, MIC and MBC of molds were not affected by these films. MIC for penicilium expansum was significantly affected when the Tio2 nanoparticles increased. Conclusion: the results indicated that Tio2 nanoparticles are applicable into the polysaccharide soy films. The nanocomposite film developed in the current study could be used in food applications and as a biodegradable film.

  10. The Optical Properties of Cu-Ni Nanoparticles Produced via Pulsed Laser Dewetting of Ultrathin Films: The Effect of Nanoparticle Size and Composition on the Plasmon Response

    International Nuclear Information System (INIS)

    Wu, Yeuyeng; Fowlkes, Jason Davidson; Rack, Philip D.

    2011-01-01

    Thin film Cu-Ni alloys ranging from 2-8nm were synthesized and their optical properties were measured as-deposited and after a laser treatment which dewet the films into arrays of spatially correlated nanoparticles. The resultant nanoparticle size and spacing are attributed to laser induced spinodal dewetting process. The evolution of the spinodal dewetting process is investigated as a function of the thin film composition which ultimately dictates the size distribution and spacing of the nanoparticles. The optical measurements of the copper rich alloy nanoparticles reveal a signature absorption peak suggestive of a plasmonic peak which red-shifts with increasing nanoparticle size and blue shifts and dampens with increasing nickel concentration.

  11. The improvement of characteristics of biodegradable films made from kefiran-whey protein by nanoparticle incorporation.

    Science.gov (United States)

    Zolfi, Mohsen; Khodaiyan, Faramarz; Mousavi, Mohammad; Hashemi, Maryam

    2014-08-30

    Biodegradable kefiran-whey protein isolate (WPI) nanocomposites were produced using montmorillonite (MMT) and nano-TiO2 as nanoparticles in the percentage of 1, 3, and 5% (w/w) by a casting and solvent-evaporation method. Physical, mechanical, and water-vapor permeability (WVP) properties were determined as a function of nanoparticle concentration. The results revealed that the effect of these nanoparticles was different according to their nature and percentage. The films incorporated with 5% (w/w) MMT showed the highest tensile strength, Young's modulus, puncture strength, and the lowest WVP compared with the control and TiO2 added films. In contrast to MMT, addition of TiO2 nanoparticles due to the plasticizing effect led to a significant change in color and transparency of nanocomposite. Scanning electron microscopy (SEM) observations demonstrated the films' properties in relation to their microstructures. The surface topography results also showed a considerable increase in roughness parameters by incorporating the nanoparticles in kefiran-WPI matrix. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Nanoparticles Stabilize Thin Polymer Films: A Fundamental Study to Understand the Phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Michael E. Mackay

    2009-03-04

    A new understanding of thermodynamics at the nanoscale resulted in a recently discovered first order phase transition that nanoparticles in a polymer film will all segregate to the supporting substrate. This is an unusual phase transition that was predicted using a modeling technique developed at Sandia National Laboratories and required the equivalent of many computational years on one computer. This project is a collaboration between Prof. Michael Mackay's group and Dr. Amalie Frischknecht (Sandia National Laboratories) where experimental observation and theoretical rationalization and prediction are brought together. Other discoveries were that this phase transition could be avoided by changing the nanoparticle properties yielding control of the assembly process at the nanoscale. In fact, the nanoparticles could be made to assemble to the supporting substrate, to the air interface or not assemble at all within a thin polymer film of order 100 nm in thickness. However, when the assembly process is present it is so robust that it is possible to make rough liquid films at the nanoscale due to nanoparticles assembling around three-dimensional objects. From this knowledge we are able to design and manufacture new coatings with particular emphasis on polymer-based solar cells. Careful control of the morphology at the nanoscale is expected to provide more efficient devices since the physics of these systems is dictated at this length scale and assembly of nanoparticles to various interfaces is critical to operation.

  13. Effect of chitosan nanoparticles and pectin content on mechanical properties and water vapor permeability of banana puree films.

    Science.gov (United States)

    Martelli, Milena R; Barros, Taís T; de Moura, Márcia R; Mattoso, Luiz H C; Assis, Odilio B G

    2013-01-01

    Puree prepared from over-ripe peeled bananas was used as raw material for films processing in a laboratory padder. Pectin and glycerol as plasticizer were added in small concentrations and chitosan nanoparticles (88.79 ± 0.42 nm medium size) incorporated at 0.2% (dry weight basis) as reinforcement material. The mechanical properties, water vapor transmission, thermal stability, and scanning electron microscopy of fractured film surfaces were characterized. Both pectin and glycerol demonstrated an important role in promoting elongation and film handability as was expected. The incorporation of nanoparticles promoted noticeable improvement of the mechanical properties and acted in reducing the water vapor permeation rate, by 21% for films processed with pectin and up to 38% for films processed without pectin, when compared to the control (puree films with no pectin and nanoparticles additions). Microscopic observation revealed a denser matrix when nanoparticles are incorporated into the films. The development of films from fruit purees head to a new strategy for plastic processing from natural resources. The over-ripe or even waste banana can be adequately prepared for batch films processed with reasonable mechanical and barrier properties, suitable for applications in the food segment. The addition of small fractions of chitosan nanoparticles, form nanocomposites enhancing mechanical and thermal stability broadening potential film applications. © 2012 Institute of Food Technologists®

  14. Antimony doped tin oxide nanoparticles and their assembly in mesostructured film

    Czech Academy of Sciences Publication Activity Database

    Müller, V.; Rasp, M.; Stefanic, G.; Günther, S.; Rathouský, Jiří; Niederberger, M.; Fattakhova-Rohlfing, D.

    2011-01-01

    Roč. 8, č. 6 (2011), s. 1759-1763 ISSN 1862-6351 R&D Projects: GA ČR GA104/08/0435 Institutional research plan: CEZ:AV0Z40400503 Keywords : transparent conducting oxides * mesoporous films * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry

  15. Molecular dynamics simulations of the embedding of a nano-particle into a polymer film

    International Nuclear Information System (INIS)

    Ochoa, J G Diaz; Binder, K; Paul, W

    2006-01-01

    In this work we report on molecular dynamics simulations of the embedding process of a nano-particle into a polymeric film as a function of temperature. This process has been employed experimentally in recent years to test for a shift of the glass transition of a material due to the confined film geometry and to test for the existence of a liquid-like layer on top of a glassy polymer film. The embedding process is governed thermodynamically by the prewetting properties of the polymer on the nano-particle. We show that the dynamics of the process depends on the Brownian motion characteristics of the nano-particle in and on the polymer film. It displays large sample to sample variations, suggesting that it is an activated process. On the timescales of the simulation an embedding of the nano-particle is only observed for temperatures above the bulk glass transition temperature of the polymer, agreeing with experimental observations on noble metal clusters of comparable size

  16. Electron transport in disordered films of metal nanoparticles linked by organic molecules

    International Nuclear Information System (INIS)

    Mueller, K.H.; Wei, G.; Herrmann, J.; Raguse, B.; Baxter, G.

    2004-01-01

    Full text: We have investigated theoretically and experimentally the mechanism of electron transport in films made of ∼10 nm sized gold nanoparticles linked by alkanedithiol molecules. Conduction in these films is due to linker-molecule assisted single-electron tunnelling between neighbouring nanoparticles where electrons have to overcome the Coulomb blockade energy. Strong disorder in our films in the form of separation gap fluctuations between adjacent nanoparticles and variations in Coulomb blockade energies cause electron current percolation. We have found that the dependence of the conduction on the length of the alkanedithiol molecules is affected by the degree of disorder. In addition, we have observed that percolation leads to a non-Arrhenius-like temperature dependence of the conduction and to a film-thickness dependent conductivity. I-V characteristics at low temperatures reveal Coulomb blockade effects. The strong dependence of the electrical conduction on the separation gaps between adjacent nanoparticles can be utilized in strain gauge and gas sensor applications

  17. Characterization of starch films containing starch nanoparticles. Part 2: viscoelasticity and creep properties.

    Science.gov (United States)

    Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

    2013-07-25

    Starch films were successfully produced by incorporating spray dried and vacuum-freeze dried starch nanoparticles. The frequency sweep, creep-recovery behavior and time-temperature superposition (TTS) on these films were studied. All these films exhibited dominant elastic behavior (than viscous behavior) over the entire frequency range (0.1-100 rad/s). The incorporation of both types of starch nanoparticles increased the storage and loss modulus, tanδ, creep strain, creep compliance and creep rate at long time frame and reduced the recovery rate of films while the effect of different kinds of starch nanoparticles on these parameters was similar both in magnitude and trend. TTS method was successfully used to predict long time (over 20 days) creep behavior through the master curves. The addition of these nanoparticles could increase the activation energy parameter used in TTS master curves. Power law and Burger's models were capable of fitting storage and loss modulus (R(2)>0.79) and creep data (R(2)>0.96), respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Nanoparticle Thin Films for Gas Sensors Prepared by Matrix Assisted Pulsed Laser Evaporation

    Directory of Open Access Journals (Sweden)

    Roberto Rella

    2009-04-01

    Full Text Available The matrix assisted pulsed laser evaporation (MAPLE technique has been used for the deposition of metal dioxide (TiO2, SnO2 nanoparticle thin films for gas sensor applications. For this purpose, colloidal metal dioxide nanoparticles were diluted in volatile solvents, the solution was frozen at the liquid nitrogen temperature and irradiated with a pulsed excimer laser. The dioxide nanoparticles were deposited on Si and Al2O3 substrates. A rather uniform distribution of TiO2 nanoparticles with an average size of about 10 nm and of SnO2 nanoparticles with an average size of about 3 nm was obtained, as demonstrated by high resolution scanning electron microscopy (SEM-FEG inspections. Gas-sensing devices based on the resistive transduction mechanism were fabricated by depositing the nanoparticle thin films onto suitable rough alumina substrates equipped with interdigitated electrical contacts and heating elements. Electrical characterization measurements were carried out in controlled environment. The results of the gas-sensing tests towards low concentrations of ethanol and acetone vapors are reported. Typical gas sensor parameters (gas responses, response/recovery time, sensitivity, and low detection limit towards ethanol and acetone are presented.

  19. Nanoparticle thin films for gas sensors prepared by matrix assisted pulsed laser evaporation.

    Science.gov (United States)

    Caricato, Anna Paola; Luches, Armando; Rella, Roberto

    2009-01-01

    The matrix assisted pulsed laser evaporation (MAPLE) technique has been used for the deposition of metal dioxide (TiO(2), SnO(2)) nanoparticle thin films for gas sensor applications. For this purpose, colloidal metal dioxide nanoparticles were diluted in volatile solvents, the solution was frozen at the liquid nitrogen temperature and irradiated with a pulsed excimer laser. The dioxide nanoparticles were deposited on Si and Al(2)O(3) substrates. A rather uniform distribution of TiO(2) nanoparticles with an average size of about 10 nm and of SnO(2) nanoparticles with an average size of about 3 nm was obtained, as demonstrated by high resolution scanning electron microscopy (SEM-FEG) inspections. Gas-sensing devices based on the resistive transduction mechanism were fabricated by depositing the nanoparticle thin films onto suitable rough alumina substrates equipped with interdigitated electrical contacts and heating elements. Electrical characterization measurements were carried out in controlled environment. The results of the gas-sensing tests towards low concentrations of ethanol and acetone vapors are reported. Typical gas sensor parameters (gas responses, response/recovery time, sensitivity, and low detection limit) towards ethanol and acetone are presented.

  20. Resonant silicon nanoparticles for enhancement of light absorption and photoluminescence from hybrid perovskite films and metasurfaces.

    Science.gov (United States)

    Tiguntseva, E; Chebykin, A; Ishteev, A; Haroldson, R; Balachandran, B; Ushakova, E; Komissarenko, F; Wang, H; Milichko, V; Tsypkin, A; Zuev, D; Hu, W; Makarov, S; Zakhidov, A

    2017-08-31

    Recently, hybrid halide perovskites have emerged as one of the most promising types of materials for thin-film photovoltaic and light-emitting devices because of their low-cost and potential for high efficiency. Further boosting their performance without detrimentally increasing the complexity of the architecture is critically important for commercialization. Despite a number of plasmonic nanoparticle based designs having been proposed for solar cell improvement, inherent optical losses of the nanoparticles reduce photoluminescence from perovskites. Here we use low-loss high-refractive-index dielectric (silicon) nanoparticles for improving the optical properties of organo-metallic perovskite (MAPbI 3 ) films and metasurfaces to achieve strong enhancement of photoluminescence as well as useful light absorption. As a result, we observed experimentally a 50% enhancement of photoluminescence intensity from a perovskite layer with silicon nanoparticles and 200% enhancement for a nanoimprinted metasurface with silicon nanoparticles on top. Strong increase in light absorption is also demonstrated and described by theoretical calculations. Since both silicon nanoparticle fabrication/deposition and metasurface nanoimprinting techniques are low-cost, we believe that the developed all-dielectric approach paves the way to novel scalable and highly effective designs of perovskite based metadevices.

  1. Preparation of pectin/silver nanoparticles composite films with UV-light barrier and properties.

    Science.gov (United States)

    Shankar, Shiv; Tanomrod, Nattareya; Rawdkuen, Saroat; Rhim, Jong-Whan

    2016-11-01

    Silver nanoparticles (AgNPs) was synthesized by a green method using an aqueous extract of Caesalpinia mimosoides Lamk (CMLE) as reducing and stabilizing agents, and they were used for the preparation of pectin-based antimicrobial composite films. The AgNPs were spherical in shape with the size in the range of 20-80nm and showed the absorption peak around 500nm. The pectin/AgNPs composite film exhibited characteristic absorption peak of AgNPs at 480nm. The surface color and light transmittance of the pectin films were greatly influenced by the addition of AgNPs. The lightness of the films decreased, however, redness and yellowness of the films increased after incorporation of AgNPs. UV-light barrier property of the pectin film increased significantly with a little decrease in the transparency. Though there were no structural changes in the pectin film by the incorporation of CMLE and AgNPs as indicated by the FTIR results, the film properties such as thermal stability, mechanical strength, and water vapor barrier properties of the pectin films increased. The pectin/AgNPs nanocomposite films exhibited strong antibacterial activity against food-borne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. k-Carrageenan/poly vinyl pyrollidone/polyethylene glycol/silver nanoparticles film for biomedical application.

    Science.gov (United States)

    Fouda, Moustafa M G; El-Aassar, M R; El Fawal, G F; Hafez, Elsayed E; Masry, Saad Hamdy Daif; Abdel-Megeed, Ahmed

    2015-03-01

    Biopolymer composite film containing k-carrageenan (KC), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) was formulated by dissolving KC and PVP in water containing PEG. Silver nanoparticles (AgNPs), was produced by Honeybee and added to solution. Finally, all solutions were poured onto dishes and dried overnight at 40°C to form the final films. Tensile strength (TS) and elongation (E %) is evaluated. The water contact angle is inspected. Thermal properties (TGA) and swelling behavior for water were considered. Fungal activity is also examined. Morphology of all films was also explored using scanning electron microscope. AgNPs induced significant hydrophilicity to KC-PVP-PEG film with contact angle of 41.6 and 34.7 for KC-PVP-PEG-AgNPs. Films with AgNPs exhibited higher thermal stability and strength properties than other films without. Films with AgNPs explore lower swelling behavior than other films without. Both SEM and EDX proved the deposition of AgNPs on the surface of films. Films with AgNPs showed higher activity against pathogenic fungi compared with the chemical fungicide; fluconazole. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Characterization of films made with chayote tuber and potato starches blending with cellulose nanoparticles.

    Science.gov (United States)

    Aila-Suárez, Selene; Palma-Rodríguez, Heidi M; Rodríguez-Hernández, Adriana I; Hernández-Uribe, Juan P; Bello-Pérez, Luis A; Vargas-Torres, Apolonio

    2013-10-15

    The aim of this study was to characterize chayotextle starch films reinforced with cellulose (C) and cellulose nanoparticle (CN) (at concentrations of 0.3%, 0.5%, 0.8% and 1.2%), using thermal, mechanical, physicochemical, permeability, and water solubility tests. C was acid-treated to obtain CN. The films were prepared by casting; potato starch and C were used as the control. The solubility of the starch films decreased with the addition of C and CN compared with its respective film without C and CN. No statistical difference (α=0.05) was found in the films added with different concentrations of C and CN. In general, the mechanical properties were improved with the addition of C and CN, and higher values of tensile strength and elastic modulus were determined in the films reinforced with CN. The melting temperature and enthalpy increased with the addition of C and CN, and the values of both thermal parameters were higher in the films with CN than with C; the enthalpy value of the film decreased when the concentration of C or CN increased in the composite. Low concentration of C and CN is better distributed in the matrix film. The addition of C and CN in the starch films improved some mechanical, barrier, and functional properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Efficient production of nanoparticle-loaded orodispersible films by process integration in a stirred media mill.

    Science.gov (United States)

    Steiner, Denise; Finke, Jan Henrik; Kwade, Arno

    2016-09-25

    Orodispersible films possess a great potential as a versatile platform for nanoparticle-loaded oral dosage forms. In this case, poorly water-soluble organic materials were ground in a stirred media mill and embedded into a polymer matrix. The aim of this study was the shortening of this manufacturing process by the integration of several process steps into a stirred media mill without facing disadvantages regarding the film quality. Furthermore, this process integration is time conserving due to the high stress intensities provided in the mill and applicable for high solids contents and high suspension viscosities. Two organic materials, the model compound Anthraquinone and the active pharmaceutical ingredient Naproxen were investigated in this study. Besides the impact of the film processing on the crystallinity of the particles in the orodispersible film, a particle load of up to 50% was investigated with the new developed processing route. Additionally, a disintegration test was developed, combining an appropriate amount of saliva substitute and a clear endpoint determination. In summary, high nanoparticle loads in orodispersible films with good particle size preservation after film redispersion in water as well as a manufacturing of the film casting mass within a few minutes in a stirred media mill was achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Microwave sintering of Ag-nanoparticle thin films on a polyimide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, S., E-mail: fujii.s.ap@m.titech.ac.jp [Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo 152-8522 (Japan); Department of Information and Communication System Engineering, National Institute of Technology, Okinawa College, Nago, Okinawa 905-2192 (Japan); Kawamura, S.; Maitani, M. M.; Suzuki, E.; Wada, Y. [Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo 152-8522 (Japan); Mochizuki, D. [Interdisciplinary Cluster for Cutting Edge Research, Center for Energy and Environmental Science, Shinshu University, Ueda, Nagano 386-8567 (Japan)

    2015-12-15

    Ag-nanoparticle thin films on a polyimide substrate were subjected to microwave sintering by use of a single-mode waveguide applicator. A two-step sintering process was employed. First, at low conductivities of the film, the film sample was placed at the site of the maximum electric field and subjected to microwave irradiation. Second, when the conductivity of the film increased, the film sample was placed at the site of the maximum magnetic field and again subjected to microwave irradiation. The microwave sintering process was completed within 1.5 min, which is significantly lower than the time required for the oven heating process. The resulting conductivity of the film, albeit only 30% of that of the bulk material, was seven times that of a film annealed at the same temperature in a furnace. Scanning electron microscopy images revealed that the nanoparticles underwent both grain necking and grain growth during microwave sintering. In addition, this sintering process was equivalent to the oven heating process performed at a 50 °C higher annealing temperature. An electromagnetic wave simulation and a heat transfer simulation of the microwave sintering process were performed to gain a thorough understanding of the process.

  6. Microwave sintering of Ag-nanoparticle thin films on a polyimide substrate

    Directory of Open Access Journals (Sweden)

    S. Fujii

    2015-12-01

    Full Text Available Ag-nanoparticle thin films on a polyimide substrate were subjected to microwave sintering by use of a single-mode waveguide applicator. A two-step sintering process was employed. First, at low conductivities of the film, the film sample was placed at the site of the maximum electric field and subjected to microwave irradiation. Second, when the conductivity of the film increased, the film sample was placed at the site of the maximum magnetic field and again subjected to microwave irradiation. The microwave sintering process was completed within 1.5 min, which is significantly lower than the time required for the oven heating process. The resulting conductivity of the film, albeit only 30% of that of the bulk material, was seven times that of a film annealed at the same temperature in a furnace. Scanning electron microscopy images revealed that the nanoparticles underwent both grain necking and grain growth during microwave sintering. In addition, this sintering process was equivalent to the oven heating process performed at a 50 °C higher annealing temperature. An electromagnetic wave simulation and a heat transfer simulation of the microwave sintering process were performed to gain a thorough understanding of the process.

  7. Controlled release of ketorolac through nanocomposite films of hydrogel and LDH nanoparticles

    International Nuclear Information System (INIS)

    Xu Zhiping; Gu Zi; Cheng Xiaoxi; Rasoul, Firas; Whittaker, Andrew K.; Lu Gaoqing Max

    2011-01-01

    A novel nanocomposite film for sustained release of anionic ophthalmic drugs through a double-control process has been examined in this study. The film, made as a drug-loaded contact lens, consists principally of a polymer hydrogel of 2-hydroxyethyl methacrylate (HEMA), in whose matrix MgAl-layered double hydroxide (MgAl-LDH) nanoparticles intercalated with the anionic drug are well dispersed. Such nanocomposite films (hydrogel-LDH-drug) contained 0.6–0.8 mg of MgAl-LDH and 0.08–0.09 mg of the ophthalmic drug (ketorolac) in 1.0 g of hydrogel. MgAl-drug-LDH nanoparticles were prepared with the hydrodynamic particle size of 40–200 nm. TEM images show that these nanoparticles are evenly dispersed in the hydrogel matrix. In vitro release tests of hydrogel-LDH-drug in pH 7.4 PBS solution at 32 °C indicate a sustained release profile of the loaded drug for 1 week. The drug release undergoes a rapid initial burst and then a monotonically decreasing rate up to 168 h. The initial burst release is determined by the film thickness and the polymerization conditions, but the following release rate is very similar, with the effective diffusion coefficient being nearly constant (3.0 × 10 −12 m 2 /s). The drug release from the films is mechanistically attributed to anionic exchange and the subsequent diffusion in the hydrogel matrix.

  8. Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

    International Nuclear Information System (INIS)

    Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

    2007-01-01

    In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

  9. Introduction of gold nanoparticles into myoglobin-Nafion film for direct electrochemistry application.

    Science.gov (United States)

    Xie, Wenting; Kong, Linlin; Kan, Meixiu; Han, Dongmei; Wang, Xueji; Zhang, Hui-Min

    2010-10-01

    An effective myoglobin-Nafion film is prepared by introducing gold nanoparticles in through a simple procedure by ion-exchange combined with electrochemical reduction. Gold nanoparticles are highly dispersed in myoglobin-Nafion film with an average size of 2.3 +/- 0.2 nm. The electrochemical behavior of myoglobin entrapped in the film has been carefully investigated with cyclic voltammetry. The results show that the introduction of gold nanoparticles into myoglobin-Nafion film makes the direct electron transfer of myoglobin efficient. A pair of well-defined redox peaks for myoglobin heme Fe(II)/Fe(III) is observed with a formal potential of -0.150 V in 0.1 M phosphate buffer (pH 7.0). The electrochemical parameters of myoglobin in the composite film are further calculated with the results of the electron-transfer rate constant (k(s)) as 0.93 s(-1) and the charge transfer coefficient (alpha) as 0.69. The experimental results also demonstrate that the immobilized myoglobin retains its electrocatalytic activity for the reduction of hydrogen peroxide and the catalytic reduction peak of myoglobin appear in a linear relationship with H2O2 concentration in the range of 10.0-235.0 microM with correlation coefficient of 0.9970. Thus fabricated Au/Mb/Nafion electrode should give a new approach for developing redox protein or enzyme-based biosensors.

  10. Organized mesoporous silica films as templates for the elaboration of organized nanoparticle networks

    International Nuclear Information System (INIS)

    Gacoin, T; Besson, S; Boilot, J P

    2006-01-01

    Tremendous work achieved in the last 20 years on nanoparticle synthesis has allowed us to study many new physical properties that are found in the nanometre size range. New developments are now expected when considering assemblies of nanoparticles such as 2D or 3D organized arrays. These systems are indeed expected to exhibit original physical properties resulting from particle-particle interactions. Studies in this field are clearly dependent on the elaboration of materials with controlled particle size, organization and interparticle distance. This paper presents a strategy of elaboration that is based on the use of organized mesoporous silica films as templates. These films are made by sol-gel polymerization around surfactant assemblies and further elimination of the surfactant. This provides porous matrices with a pore organization that is the almost perfect replica of the initial micellar structure. The use of such films for the elaboration of organized arrays of nanoparticles is detailed in the case of CdS and Ag particles. The formation of particles inside the pores is achieved through impregnation with precursors that are allowed to diffuse inside the pores. This leads to particles with a size and a spatial arrangement that is directly related to the initial pore structure of the films. This process opens a wide range of investigations due to the relative ease of fabrication over large surfaces and the numerous possibilities offered by the elaboration of porous films with different pore sizes and organizations

  11. Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

    2007-10-15

    In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

  12. Plasma treatment of ITO films for the formation of nanoparticles toward scalable production of novel nanostructure-based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Cigang; Bailey, Louise R.; Proudfoot, Gary; Cooke, Mike [Oxford Instruments Plasma Technology, Bristol (United Kingdom); Eisenhawer, Bjoern; Jia, Guobin; Bergmann, Joachim; Falk, Fritz [Leibniz Institute of Photonic Technology, Jena (Germany); Ulyashin, Alexander [Department of Industrial Processes, SINTEF, Oslo (Norway)

    2015-01-01

    Plasma treatment of indium tin oxide (ITO) has been studied to form metallic nanoparticles (NPs) for nanostructure-based solar cells. It is demonstrated that NPs can be formed at temperatures as low as 100 C, and the size of NPs increases with temperature. An ITO layer treated at 100 C has higher transmission than that treated at 200 C for the same time. It is suggested that such NPs can be used for the conversion efficiency enhancement of ITO/Si heterojunction solar cells. It is also shown that NPs can be produced on different substrates covered by an ITO layer, such as ITO/Al foil, ITO/glass, ITO/stainless steel, and ITO/Si, where the resulting NPs were used for catalytic growth of Si nanowires (NWs). The morphology and density of Si NWs depend on a substrate. It is established that p-doped Si NWs show larger diameters, and n-doped Si NWs do not show obvious change of diameters compared to undoped Si NWs. New types of solar cell structures with combined radial and axial junctions have been proposed. As an example, p-n junction-based 3D structures using the NPs obtained from treatment of ITO film are presented. Finally, a potentially scalable process flow for fabrication of nanostructure-based solar cells is discussed. Schematic illustration of fabrication steps to produce the proposed novel solar cell with combined radial and axial junctions. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke, E-mail: dnagao@tohoku.ac.jp; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

    2016-09-15

    Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO{sub 2} nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

  14. Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, William D.; Miller, James B. [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Yolcu, Cem [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Gellman, Andrew J., E-mail: gellman@cmu.edu [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2012-11-01

    Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: Black-Right-Pointing-Pointer Pd dewetting from SiN occurs by a spinodal dewetting mechanism. Black-Right-Pointing-Pointer Dewetting occurs at temperatures well below the

  15. Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

    International Nuclear Information System (INIS)

    Michalak, William D.; Miller, James B.; Yolcu, Cem; Gellman, Andrew J.

    2012-01-01

    Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: ► Pd dewetting from SiN occurs by a spinodal dewetting mechanism. ► Dewetting occurs at temperatures well below the melting point of Pd. ► Spinodal dewetting allows

  16. Synthesis and characterization of permalloy nanostructured films by deposition of laser ablated nanoparticles

    International Nuclear Information System (INIS)

    Huang, Chong; Yun, Eui-Jung; Ma, James; Keto, John W.; Becker, Michael F.; Kovar, Desiderio

    2009-01-01

    A permalloy (Ni 81 Fe 19 ; at%) microparticle (MP) aerosol was ablated to produce a nanoparticle (NP) aerosol that was then impacted at high velocity onto a substrate to produce porous thick films. The structure of the NPs was analyzed by transmission electron microscopy and the morphologies of the NPs and the nanostructured films were studied using high-resolution transmission electron microscopy and scanning electron microscopy. These analyses showed that the original composition and structure of the MPs were preserved in the NPs and films. The majority of NPs that were produced ranged in size between 2 and 15 nm with some larger particles present. Magnetization-temperature curves showed that the films consisted of a mixture of small superparamagnetic NPs and larger ferromagnetic NPs. A high saturation magnetization of 62.3 emu/g at 300 K was retained in the films indicating that they remained free of significant oxidation.

  17. Zinc oxide nanoparticle-coated films: fabrication, characterization, and antibacterial properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yunhong, E-mail: y.jiang@leeds.ac.uk [University of Leeds, Institute of Particle Science and Engineering (United Kingdom); O’Neill, Alex J. [University of Leeds, School of Molecular and Cellular Biology (United Kingdom); Ding, Yulong [University of Leeds, Institute of Particle Science and Engineering (United Kingdom)

    2015-04-15

    In this article, novel antibacterial PVC-based films coated with ZnO nanoparticles (NPs) were fabricated, characterized, and studied for their antibacterial properties. It was shown that the ZnO NPs were coated on the surface of the PVC films uniformly and that the coating process did not affect the size and shape of the NPs on the surface of PVC films. Films coated with concentrations of either 0.2 or 0.075 g/L of ZnO NPs exhibited antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, but exhibited no antifungal activity against Aspergillus flavus and Penicillium citrinum. Smaller particles (100 nm) exhibited more potent antibacterial activity than larger particles (1000 nm). All ZnO-coated films maintained antibacterial activity after 30 days in water.

  18. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films

    Science.gov (United States)

    Kim, Jin Young; Adinolfi, Valerio; Sutherland, Brandon R.; Voznyy, Oleksandr; Kwon, S. Joon; Kim, Tae Wu; Kim, Jeongho; Ihee, Hyotcherl; Kemp, Kyle; Adachi, Michael; Yuan, Mingjian; Kramer, Illan; Zhitomirsky, David; Hoogland, Sjoerd; Sargent, Edward H.

    2015-01-01

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles—yet size–effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector. PMID:26165185

  19. Guided assembly of nanoparticles on electrostatically charged nanocrystalline diamond thin films

    Directory of Open Access Journals (Sweden)

    Verveniotis Elisseos

    2011-01-01

    Full Text Available Abstract We apply atomic force microscope for local electrostatic charging of oxygen-terminated nanocrystalline diamond (NCD thin films deposited on silicon, to induce electrostatically driven self-assembly of colloidal alumina nanoparticles into micro-patterns. Considering possible capacitive, sp2 phase and spatial uniformity factors to charging, we employ films with sub-100 nm thickness and about 60% relative sp2 phase content, probe the spatial material uniformity by Raman and electron microscopy, and repeat experiments at various positions. We demonstrate that electrostatic potential contrast on the NCD films varies between 0.1 and 1.2 V and that the contrast of more than ±1 V (as detected by Kelvin force microscopy is able to induce self-assembly of the nanoparticles via coulombic and polarization forces. This opens prospects for applications of diamond and its unique set of properties in self-assembly of nano-devices and nano-systems.

  20. Blue shift in the luminescence spectra of MEH-PPV films containing ZnO nanoparticles

    International Nuclear Information System (INIS)

    Ton-That, Cuong; Phillips, Matthew R.; Nguyen, Thien-Phap

    2008-01-01

    Luminescence properties of nanocomposites consisting of ZnO nanoparticles in a conjugated polymer, poly [2-methoxy-5-(2'-ethyl hexyloxy)-phenylene vinylene] (MEH-PPV), were investigated. Photoluminescence measurements reveal a blue shift in the emission spectrum of MEH-PPV upon incorporation of ZnO nanoparticles into the polymer film while the emission is increasingly quenched with increasing ZnO concentration. In contrast, the structure of the polymer and its conjugation length are not affected by the presence of ZnO nanoparticles (up to 16 wt% ZnO) as revealed by Raman spectroscopy. The blue shift and photoluminescence quenching are explained by the separation of photogenerated electron-hole pairs at the MEH-PPV/ZnO interface and the charging of the nanoparticles

  1. Nanostructures from nanoparticles

    International Nuclear Information System (INIS)

    Mendes, Paula M; Chen Yu; Palmer, Richard E; Nikitin, Kirill; Fitzmaurice, Donald; Preece, Jon A

    2003-01-01

    This paper reviews recent experimental approaches to the development of surface nanostructures from nanoparticles. The formation of nanowires by electron beam writing in films of gold nanoparticles passivated with a specially designed class of ligand molecules (dialkyl sulfides) is presented, together with illustrations of practical nanostructures. Potential applications of this methodology are discussed. Another alternative to the controlled fabrication of arrays of nanoparticles, based on nanocrystals which contain molecular recognition elements in the ligand shell, is also surveyed. These particles aggregate in the presence of specifically designed molecular dications which act as a molecular binder. Finally, recent work on the formation of nanoscale surface architectures using x-ray patterning of self-assembled monolayers is introduced. Current and potential future applications of these surface nanostructures are discussed

  2. Evaluation of the genotoxicity of chitosan nanoparticles for use in food packaging films.

    Science.gov (United States)

    De Lima, Renata; Feitosa, Leandro; do Espírito Santo Pereira, Anderson; de Moura, Márcia Regina; Ahmad Aouada, Fauze; Henrique Capparelli Mattoso, Luiz; Fernandes Fraceto, Leonardo

    2010-08-01

    The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging.

  3. Controlling Growth High Uniformity Indium Selenide (In2Se3) Nanowires via the Rapid Thermal Annealing Process at Low Temperature.

    Science.gov (United States)

    Hsu, Ya-Chu; Hung, Yu-Chen; Wang, Chiu-Yen

    2017-09-15

    High uniformity Au-catalyzed indium selenide (In 2 Se 3) nanowires are grown with the rapid thermal annealing (RTA) treatment via the vapor-liquid-solid (VLS) mechanism. The diameters of Au-catalyzed In 2 Se 3 nanowires could be controlled with varied thicknesses of Au films, and the uniformity of nanowires is improved via a fast pre-annealing rate, 100 °C/s. Comparing with the slower heating rate, 0.1 °C/s, the average diameters and distributions (standard deviation, SD) of In 2 Se 3 nanowires with and without the RTA process are 97.14 ± 22.95 nm (23.63%) and 119.06 ± 48.75 nm (40.95%), respectively. The in situ annealing TEM is used to study the effect of heating rate on the formation of Au nanoparticles from the as-deposited Au film. The results demonstrate that the average diameters and distributions of Au nanoparticles with and without the RTA process are 19.84 ± 5.96 nm (30.00%) and about 22.06 ± 9.00 nm (40.80%), respectively. It proves that the diameter size, distribution, and uniformity of Au-catalyzed In 2 Se 3 nanowires are reduced and improved via the RTA pre-treated. The systemic study could help to control the size distribution of other nanomaterials through tuning the annealing rate, temperatures of precursor, and growth substrate to control the size distribution of other nanomaterials. Graphical Abstract Rapid thermal annealing (RTA) process proved that it can uniform the size distribution of Au nanoparticles, and then it can be used to grow the high uniformity Au-catalyzed In 2 Se 3 nanowires via the vapor-liquid-solid (VLS) mechanism. Comparing with the general growth condition, the heating rate is slow, 0.1 °C/s, and the growth temperature is a relatively high growth temperature, > 650 °C. RTA pre-treated growth substrate can form smaller and uniform Au nanoparticles to react with the In 2 Se 3 vapor and produce the high uniformity In 2 Se 3 nanowires. The in situ annealing TEM is used to realize the effect of heating

  4. Conduction and reversible memory phenomena in Au-nanoparticles-incorporated TeO{sub 2}–ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Bontempo, L., E-mail: bontempo@usp.br [Laboratório de Sistemas Integráveis, Escola Politécnica da Universidade de São Paulo, Av. Prof. Luciano Gualberto, 158, Travessa 3, 05508-900 São Paulo, SP (Brazil); Laboratório de Materiais Fotônicos e Optoeletrônicos, Faculdade de Tecnologia de São Paulo, Praça Cel. Fernando Prestes, 30, 01124-060 São Paulo, SP (Brazil); Santos Filho, S.G. dos, E-mail: sgsantos@usp.br [Laboratório de Sistemas Integráveis, Escola Politécnica da Universidade de São Paulo, Av. Prof. Luciano Gualberto, 158, Travessa 3, 05508-900 São Paulo, SP (Brazil); Kassab, L.R.P., E-mail: kassablm@osite.com.br [Laboratório de Materiais Fotônicos e Optoeletrônicos, Faculdade de Tecnologia de São Paulo, Praça Cel. Fernando Prestes, 30, 01124-060 São Paulo, SP (Brazil)

    2016-07-29

    A reversible memory behavior in TeO{sub 2}–ZnO thin films containing Au nanoparticles prepared using the sputtering technique has been observed. The current–voltage characteristics of the films, having Al and Si as electrodes, showed a switching behavior starting from an initial state of low conductivity to a high conductivity one. As a result, an abrupt increase of current (10{sup −7} to 10{sup −3} A) was observed for 6.5 V (100 nm thickness). Au nanoparticles provide a larger electron storage capability, and do not favor the transport through the insulator; they present a higher trapped charge concentration, which reduces the leakage current to lower levels. The influence of the Au nanoparticle diameter and volumetric concentration to reach the abrupt current transition and the value of the transition voltage was studied. These parameters were found to play an important role on reversible memory phenomena as they determine the facility/difficulty to fill and saturate the traps (Au nanoparticles) with electrons. - Highlights: • TeO{sub 2}–ZnO thin films with Au nanoparticles grown by magnetron co-sputtering for memory devices • Nucleation of gold nanoparticles by annealing process • Electrical properties of TeO{sub 2}–ZnO thin films with and without gold nanoparticles • Reversible memory phenomenum in Au-nanoparticles-incorporated TeO{sub 2}–ZnO thin films.

  5. Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Md Taibur; McCloy, John; Panat, Rahul, E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99163 (United States); Ramana, C. V., E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

    2016-08-21

    Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

  6. Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

    International Nuclear Information System (INIS)

    Rahman, Md Taibur; McCloy, John; Panat, Rahul; Ramana, C. V.

    2016-01-01

    Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

  7. Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

    Science.gov (United States)

    Rahman, Md Taibur; McCloy, John; Ramana, C. V.; Panat, Rahul

    2016-08-01

    Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24-500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

  8. Nanoparticle Encapsulation in Diblock Copolymer/Homopolymer Blend Thin Film Mixtures

    Science.gov (United States)

    Zhao, Junnan; Chen, Xi; Green, Peter

    2014-03-01

    We investigated the organization of low concentrations of poly (2-vinylpyridine) (P2VP) grafted gold nanoparticles within a diblock copolymer polystyrene-b-poly (2-vinylpyridine) (PS-b-P2VP)/homopolymer polystyrene (PS) blend thin film. The PS-b-P2VP copolymers formed micelles, composed of inner cores of P2VP block and outer coronae of PS blocks, throughout the homopolymer PS. All nanoparticles were encapsulated within micelle cores and each micelle contained one or no nanoparticle, on average. When the host PS chains are much longer than corona chains, micelles tended to self-organize at the interfaces. Otherwise, they were dispersed throughout the PS host. In comparison to the neat PS-b-P2VP/PS blend, the nanoparticles/PS-b-P2VP/PS system had a higher density of smaller micelles, influenced largely by the number of nanoparticles in the system. The behavior of this system is understood in terms of the maximization of the nanoparticle/micelle core interactions and of the translational entropies of the micelles and the nanoparticles.

  9. Modification of physicochemical and thermal properties of starch films by incorporation of TiO2 nanoparticles.

    Science.gov (United States)

    Oleyaei, Seyed Amir; Zahedi, Younes; Ghanbarzadeh, Babak; Moayedi, Ali Akbar

    2016-08-01

    In this research, potato starch and TiO2 nanoparticles (0.5, 1 and 2wt%) films were developed. Influences of different concentrations of TiO2 on the functional properties of nanocomposite films (water-related properties, mechanical characteristics, and UV transmittance) were investigated. XRD, FTIR, and DSC analyses were used to characterize the morphology and thermal properties of the films. The results revealed that TiO2 nanoparticles dramatically decreased the values of water-related properties (water vapor permeability: 11-34%; water solubility: 1.88-9.26%; moisture uptake: 2.15-11.18%). Incorporation of TiO2 led to a slight increment of contact angle and tensile strength, and a decrease in elongation at break of the films. TiO2 successfully blocked more than 90% of UV light, while opacity and white index of the films were enhanced. Glass transition temperature and melting point of the films were positively affected by the addition of TiO2 nanoparticles. The result of XRD study exhibited that due to a limited agglomeration of TiO2 nanoparticles, the mean crystal size of TiO2 increased. Formation of new hydrogen bonds between the hydroxyl groups of starch and nanoparticles was confirmed by FTIR spectroscopy. In conclusion, TiO2 nanoparticles improved the functional properties of potato starch film and extended the potential for food packaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Green synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films

    Science.gov (United States)

    Dinh, D. A.; Hui, K. S.; Hui, K. N.; Cho, Y. R.; Zhou, Wei; Hong, Xiaoting; Chun, Ho-Hwan

    2014-04-01

    A green facile chemical approach to control the dimensions of Ag nanoparticles-graphene oxide (AgNPs/GO) composites was performed by the in situ ultrasonication of a mixture of AgNO3 and graphene oxide solutions with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N2/H2 gas flow for 1 h. Four-point probe measurements showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). The formation mechanisms of the as-prepared AgNPs/rGO films are proposed. This study provides a guide to controlling the dimensions of AgNPs/rGO films, which might hold promise as advanced materials for a range of analytical applications, such as catalysis, sensors and microchips.

  11. One-Step Process for High-Performance, Adhesive, Flexible Transparent Conductive Films Based on p-Type Reduced Graphene Oxides and Silver Nanowires.

    Science.gov (United States)

    Lai, Yi-Ting; Tai, Nyan-Hwa

    2015-08-26

    This work demonstrates a one-step process to synthesize uniformly dispersed hybrid nanomaterial containing silver nanowires (AgNWs) and p-type reduced graphene (p-rGO). The hybrid nanomaterial was coated onto a polyethylene terephthalate (PET) substrate for preparing high-performance flexible transparent conductive films (TCFs). The p-rGO plays the role of bridging discrete AgNWs, providing more electron holes and lowering the resistance of the contacted AgNWs; therefore, enhancing the electrical conductivity without sacrificing too much transparence of the TCFs. Additionally, the p-rGO also improves the adhesion between AgNWs and substrate by covering the AgNWs on the substrate tightly. The study shows that coating of the hybrid nanomaterials on the PET substrate demonstrates exceptional optoelectronic properties with a transmittance of 94.68% (at a wavelength of 550 nm) and a sheet resistance of 25.0 ± 0.8 Ω/sq. No significant variation in electric resistance can be detected even when the film was subjected to a bend loading with a radius of curvature of 5.0 mm or the film was loaded with a reciprocal tension or compression for 1000 cycles. Furthermore, both chemical corrosion resistance and haze effect were improved when p-rGO was introduced. The study shows that the fabricated flexible TCFs have the potential to replace indium tin oxide film in the optoelectronic industry.

  12. Time-resolved analysis of the white photoluminescence from chemically synthesized SiC_xO_y thin films and nanowires

    International Nuclear Information System (INIS)

    Tabassum, Natasha; Nikas, Vasileios; Ford, Brian; Huang, Mengbing; Kaloyeros, Alain E.; Gallis, Spyros

    2016-01-01

    The study reported herein presents results on the room-temperature photoluminescence (PL) dynamics of chemically synthesized SiC_xO_y_≤_1_._6 (0.19 < x < 0.6) thin films and corresponding nanowire (NW) arrays. The PL decay transients of the SiC_xO_y films/NWs are characterized by fast luminescence decay lifetimes that span in the range of 350–950 ps, as determined from their deconvoluted PL decay spectra and their stretched-exponential recombination behavior. Complementary steady-state PL emission peak position studies for SiC_xO_y thin films with varying C content showed similar characteristics pertaining to the variation of their emission peak position with respect to the excitation photon energy. A nearly monotonic increase in the PL energy emission peak, before reaching an energy plateau, was observed with increasing excitation energy. This behavior suggests that band-tail states, related to C-Si/Si-O-C bonding, play a prominent role in the recombination of photo-generated carriers in SiC_xO_y. Furthermore, the PL lifetime behavior of the SiC_xO_y thin films and their NWs was analyzed with respect to their luminescence emission energy. An emission-energy-dependent lifetime was observed, as a result of the modulation of their band-tail states statistics with varying C content and with the reduced dimensionality of the NWs.

  13. Polypropylene film with silver nanoparticles and nanoclay aiming to action biocidal

    International Nuclear Information System (INIS)

    Oliani, W.L.; Lima, L.F.C.P.; Lugao, A.B.; Parra, D.F.; Fermino, D.M.; Diaz, F.R.V.

    2014-01-01

    This paper presents an initial study of films made of polypropylene nanoclay and silver nanoparticles. The nanocomposite of polypropylene (iPP), commercial organoclay - montmorillonite (MMT), Cloisite 20A at concentrations of 1.0% and silver nanoparticles (AgNPs) at a concentration of 0.1% were prepared in a twin-screw-extruder, using polypropylene with maleic anhydride (PP-g-MA) as coupling agent. The properties of nanocomposites of PP/MMT/AgNPs are closely related to the dispersion of silver particles and the distribution of sheets of MMT in the polymer matrix, which define its efficiency in the case of the particles and their interaction clay/polymer matrix. However, this combination of MMT and AgNPs that are polar, with the polymer matrix nonpolar in the molten state, presents a challenge. The characterization of the film was performed by analysis of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and reduction of colony forming unit (CFU %). The results indicate the formation of predominantly exfoliated microstructures and agglomeration of silver nanoparticles in the film. The effect of silver nanoparticles was evaluated against bacteria E.coli and S.aureus. (author)

  14. Silver Nanoparticles Synthesized Using Mint Extract and their Application in Chitosan/Gelatin Composite Packaging Film

    Science.gov (United States)

    Bhoir, Shraddha A.; Chawla, S. P.

    The present study reports synthesis of silver nanoparticles (AgNPs) using mint extract (ME) in the presence of polyvinyl alcohol (PVA) as capping material. PVA, ME and silver nitrate at concentration of 1%, 0.01% and 0.02%, respectively were found to be optimum for the synthesis of nanoparticles. The formation of AgNPs was confirmed by measuring surface plasmon resonance (SPR) peak. The intensity of SPR peak remained unaltered thus suggesting stability of colloid without aggregation during storage. The nanoparticles inhibited the growth of food borne bacteria namely Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. The incorporation of these nanoparticles in chitosan and gelatin blend resulted in homogenous films. Mechanical properties and water vapor transmission rate of chitosan-gelatin films improved due to addition of AgNPs, whereas optical (opacity and UV light transmittance) and oxygen permeability properties remained unchanged. These films had the ability to inhibit growth of 5 log CFU of the above test organisms. These findings suggest that the AgNPs obtained by reduction of silver by ME can be effectively utilized to prepare antibacterial eco-friendly food packaging material.

  15. Transport properties of β-Ga2O3 nanoparticles embedded in Nb thin films

    Directory of Open Access Journals (Sweden)

    L.S. Vaidhyanathan

    2015-01-01

    Full Text Available The origin of ferromagnetism in nanoparticles of nonmagnetic oxides is an interesting area of research. In the present work, transport properties of niobium thin films, with β-Ga2O3 nanoparticles embedded within them, are presented. Nanoparticles of β-Ga2O3 embedded in a Nb matrix were prepared at room temperature by radio frequency co-sputtering technique on Si (100 and glass substrates held at room temperature. The thin films deposited on Si substrates were subjected to Ar annealing at a temperature range of 600-650 C for 1 hour. Films were characterized by X-ray diffraction (XRD, Micro-Raman and elemental identification was performed with an Energy Dispersive X-ray Spectroscopy (EDS. Transport measurements were performed down to liquid helium temperatures by four-probe contact technique, showed characteristics analogous to those observed in the context of a Kondo system. A comparison of the experimental data with the theoretical formalism of Kondo and Hamann is presented. It is suggested that this behavior arises from the existence of magnetic moments associated with the oxygen vacancy defects in the nanoparticles of the nonmagnetic oxide Ga2O3.

  16. Fabrication of conducting polymer-gold nanoparticles film on electrodes using monolayer protected gold nanoparticles and its electrocatalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Palanisamy [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India); School of Chemical and Biomedical Engineering, N1.3, B4-01, 70 Nanyang Drive, Nanyang Technological University, Singapore 637457 (Singapore); John, S. Abraham, E-mail: abrajohn@yahoo.co.in [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India)

    2011-08-01

    We wish to report a simple and new strategy for the fabrication of gold nanoparticles-conducting polymer film on glassy carbon (GC) and indium tin oxide (ITO) surfaces using 5-amino-2-mercapto-1,3,4-thiadiazole capped gold nanoparticles (AMT-AuNPs) in 0.01 M H{sub 2}SO{sub 4} by electropolymerization. The presence of amine groups on the surface of the AuNPs was responsible for the deposition of the AMT-AuNPs film on the electrode surface. The atomic force microscopy (AFM) studies reveal that the fabricated p-AMT-AuNPs film showed homogeneously distributed AuNPs with a spherical shape of {approx}8 nm diameter. The XPS spectrum shows the binding energies at 83.8 and 87.5 eV in the Au 4f region corresponding to 4f{sub 7/2} and 4f{sub 5/2}, respectively. The position and difference between these two peaks (3.7 eV) exactly match the value reported for Au{sup 0}. The N1s XPS showed three binding energies at 396.7, 399.6 and 403.3 eV, corresponding to the =NH, -NH- and -N{sup +}H-, respectively, confirming that the electropolymerization proceeded through the oxidation of -NH{sub 2} groups present on the periphery of the AMT-AuNPs. The application of the present p-AMT-AuNPs modified electrode was demonstrated by studying the electro reduction of oxygen at pH 7.2. The p-AMT-AuNPs film enhanced the oxygen reduction current more than three times than that of p-AMT film prepared under identical conditions.

  17. UV absorption by cerium oxide nanoparticles/epoxy composite thin films

    International Nuclear Information System (INIS)

    Dao, Ngoc Nhiem; Luu, Minh Dai; Nguyen, Quang Khuyen; Kim, Byung Sun

    2011-01-01

    Cerium oxide (CeO 2 ) nanoparticles have been used to modify properties of an epoxy matrix in order to improve the ultra-violet (UV) absorption property of epoxy thin films. The interdependence of mechanical properties, UV absorption property and the dispersed concentration of CeO 2 nanoparticles was investigated. Results showed that, by increasing the dispersed concentration of CeO 2 nanoparticles up to 3 wt%, tensile modulus increases while two other mechanical properties, namely tensile strength and elongation, decrease. The UV absorption peak and the absorption edges of the studied thin films were observed in the UV-Vis absorption spectra. By incorporating CeO 2 nanoparticles into the epoxy matrix, an absorption peak appears at around 318 nm in UV-Vis spectra with increasing CeO 2 concentration from 0.1 to 1.0 wt%. Scanning electron microscopy (SEM) images revealed that a good dispersion of nanoparticles in the epoxy matrix by an ultrasonic method was achieved

  18. Biotemplated Synthesis of PZT Nanowires

    Science.gov (United States)

    2013-11-25

    electromechanical coupling coefficient , Y is the Young’s modulus, and Ri is intrinsic resistance. The PZT nanowire- based film is taken to have negligible...robotic actuation, and bioMEMS. Lead zirconate titanate ( PZT ), in particular, has attracted significant attention, owing to its superior...electromechanical conversion performance. Yet, the ability to synthesize crystalline PZT nanowires with reproducible and well-controlled properties remains a

  19. Growth and characterization of NixCu1-x alloy films, NixCu1-x/NiyCu1-y multilayers, and nanowires

    International Nuclear Information System (INIS)

    Kazeminezhad, I.

    2001-12-01

    It was found that it is possible to grow Ni x Cu 1-x alloy systems of arbitrary composition by electrodepositing well-defined sub-monolayer quantities of Ni and Cu in alternation using a new method based on that used previously to prepare potentiostatically deposited magnetic multilayers from a single sulphamate-based electrolyte. Following growth, the chemical composition of Ni x Cu 1-x alloy films was obtained by ZAF-corrected energy dispersive X-Ray (EDX) analysis and less than a 4% difference between the nominal and actual composition was observed. The structure of the films was investigated by high-angle X-ray diffractometry (HAXRD) and transmission electron microscopy (TEM). The films grown on polycrystalline Cu substrates had (100) texture, while those grown on Au-coated glass had (111) texture. Some evidence of Ni clustering was obtained by vibrating sample magnetometry (VSM). Self-organisation of the deposited metal was suggested for Ni potentials more positive than ∼-1.4V. The transition from a Ni/Cu multilayer to a Ni x Cu 1-x alloy was also studied and an interesting aspect, namely a plateau region in a plot of magnetisation as a function of Ni layer thickness was observed, suggesting a preferred Ni cluster size in these alloy films. Anisotropic magnetoresistance (AMR) of the films decreased with increasing Cu content at 300K and 77K. SQUID measurements for Ni 0.52 Cu 0.48 and Ni 0.62 CU 0.38 films showed that they become much more strongly ferromagnetic at low temperatures. Evidence for blocked -superparamagnetic behaviour above a blocking temperature (T B ) of the films was obtained from zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility measurements. Ni x Cu 1-x /Ni y Cu 1-y alloy/alloy multilayer films with short repeat distance were successfully fabricated using this method. Up to third order satellite peaks observed in HAXRD showed that the interface is sharp. Room temperature longitudinal magnetoresistance measurements showed

  20. High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates.

    Science.gov (United States)

    Li, Xue; Lau, King Hang Aaron; Kim, Dong Ha; Knoll, Wolfgang

    2005-05-24

    Highly dense arrays of titania nanoparticles were fabricated using surface micellar films of poly(styrene-block-2-vinylpyridine) diblock copolymers (PS-b-P2VP) as reaction scaffolds. Titania could be introduced selectively within P2VP nanodomains in PS-b-P2VP films through the binary reaction between water molecules trapped in the P2VP domains and the TiCl(4) vapor precursors. Subsequent UV exposure or oxygen plasma treatment removed the organic matrix, leading to titania nanoparticle arrays on the substrate surface. The diameter of the titania domains and the interparticle distance were defined by the lateral scale present in the microphase-separated morphology of the initial PS-b-P2VP films. The typical diameter of titania nanoparticles obtained by oxygen plasma treatment was of the order of approximately 23 nm. Photoluminescence (PL) properties were investigated for films before and after plasma treatment. Both samples showed PL properties with major physical origin due to self-trapped excitons, indicating that the local environment of the titanium atoms is similar.

  1. Large enhancement of Faraday rotation by localized surface plasmon resonance in Au nanoparticles embedded in Bi:YIG film

    International Nuclear Information System (INIS)

    Uchida, H.; Masuda, Y.; Fujikawa, R.; Baryshev, A.V.; Inoue, M.

    2009-01-01

    A large enhancement of the Faraday rotation, which is associated with localized surface plasmon resonance (LSPR), was obtained in a sample with Au nanoparticles embedded in a Bi-substituted yttrium iron garnet (Bi:YIG) film. On a quartz substrate, Au nanoparticles were formed by heating an Au thin film, and a Bi:YIG film was then deposited on them. A sample containing the Au nanoparticles produced by 1000 deg. C heating showed a resonant attenuation with narrower bandwidth in the transmission spectrum than nanoparticles of other samples formed by low-temperature heating. The sharp resonant Faraday rotation angle was 4.4 times larger than the estimated intrinsic Bi:YIG film at the LSPR wavelength; the angular difference was 0.14 deg. A discrepancy in the bandwidth between the transmission attenuation and the resonant Faraday rotation is discussed

  2. Optical Design of Textured Thin-Film CIGS Solar Cells with Nearly-Invisible Nanowire Assisted Front Contacts

    Directory of Open Access Journals (Sweden)

    Joop van Deelen

    2017-04-01

    Full Text Available The conductivity of transparent front contacts can be improved by patterned metallic nanowires, albeit at the cost of optical loss. The associated optical penalty can be strongly reduced by texturization of the cell stack. Remarkably, the nanowires themselves are not textured and not covered in our design. This was shown by optical modeling where the width of the nanowire, the texture height and the texture period were varied in order to obtain a good insight into the general trends. The optical performance can be improved dramatically as the reflection, which is the largest optical loss, can be reduced by 95% of the original value. The spectra reveal absorption in the Cu(In,GaSe2 (CIGS layer of 95% and reflection below 2% over a large part of the spectrum. In essence, a virtually black CIGS cell stack can be achieved for textured cells with a metal nanogrid. Moreover, it turned out that the ratio between the width of the nanowire and the height of the texture is a critical parameter for optical losses.

  3. High magnetic field matching effects in NbN films induced by template grown dense ferromagnetic nanowires arrays

    DEFF Research Database (Denmark)

    Hallet, X.; Mátéfi-Tempfli, Mária; Michotte, S.

    2009-01-01

    magnetic nanowires. Matching effects have been observed up to 2.5 T (11th matching field) and are maintained at low temperature. An appreciable enhancement of the superconducting properties is observed. At low fields, a hysteretic behavior in the magnetoresistance is found, directly related...

  4. Gold nanoparticle plasmon resonance in near-field coupled Au NPs layer/Al film nanostructure: Dependence on metal film thickness

    Science.gov (United States)

    Yeshchenko, Oleg A.; Kozachenko, Viktor V.; Naumenko, Antonina P.; Berezovska, Nataliya I.; Kutsevol, Nataliya V.; Chumachenko, Vasyl A.; Haftel, Michael; Pinchuk, Anatoliy O.

    2018-05-01

    We study the effects of coupling between plasmonic metal nanoparticles and a thin metal film by using light extinction spectroscopy. A planar monolayer of gold nanoparticles located near an aluminum thin film (thicknesses within the range of 0-62 nm) was used to analyze the coupling between the monolayer and the thin metal film. SPR peak area increase for polymer coated Au NPs, non-monotonical behavior of the peak area for bare Au NPs, as well as red shift and broadening of SPR at the increase of the Al film thickness have been observed. These effects are rationalized as a result of coupling of the layer of Au NPs with Al film through the field of localized surface plasmons in Au NPs that causes the excitation of collective plasmonic gap mode in the nanostructure. An additional mechanism for bare Au NPs is the non-radiative damping of SPR that is caused by the electrical contact between metal NPs and film.

  5. Fabrication of Si/ZnS radial nanowire heterojunction arrays for white light emitting devices on Si substrates.

    Science.gov (United States)

    Katiyar, Ajit K; Sinha, Arun Kumar; Manna, Santanu; Ray, Samit K

    2014-09-10

    Well-separated Si/ZnS radial nanowire heterojunction-based light-emitting devices have been fabricated on large-area substrates by depositing n-ZnS film on p-type nanoporous Si nanowire templates. Vertically oriented porous Si nanowires on p-Si substrates have been grown by metal-assisted chemical etching catalyzed using Au nanoparticles. Isolated Si nanowires with needle-shaped arrays have been made by KOH treatment before ZnS deposition. Electrically driven efficient white light emission from radial heterojunction arrays has been achieved under a low forward bias condition. The observed white light emission is attributed to blue and green emission from the defect-related radiative transition of ZnS and Si/ZnS interface, respectively, while the red arises from the porous surface of the Si nanowire core. The observed white light emission from the Si/ZnS nanowire heterojunction could open up the new possibility to integrate Si-based optical sources on a large scale.

  6. Biodegradable starch/poly (vinyl alcohol) film reinforced with titanium dioxide nanoparticles

    Science.gov (United States)

    Hejri, Zahra; Seifkordi, Ali Akbar; Ahmadpour, Ali; Zebarjad, Seyed Mojtaba; Maskooki, Abdolmajid

    2013-10-01

    Biodegradable starch/poly (vinyl alcohol)/nano-titanium dioxide (ST/PVA/nano-TiO2) nanocomposite films were prepared via a solution casting method. Their biodegradability, mechanical properties, and thermal properties were also studied in this paper. A general full factorial experimental approach was used to determine effective parameters on the mechanical properties of the prepared films. ST/PVA/TiO2 nanocomposites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results of mechanical analysis show that ST/PVA films with higher contents of PVA have much better mechanical properties. In thermal analysis, it is found that the addition of TiO2 nanoparticles improves the thermal stability of the films. SEM micrographs, taken from the fracture surface of samples, illustrate that the addition of PVA makes the film softer and more flexible. The results of soil burial biodegradation indicate that the biodegradability of ST/PVA/TiO2 films strongly depends on the starch proportion in the film matrix. The degradation rate is increased by the addition of starch in the films.

  7. Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

    International Nuclear Information System (INIS)

    Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

    2016-01-01

    Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

  8. Work function measurements of copper nanoparticle intercalated polyaniline nanocomposite thin films

    Science.gov (United States)

    Patil, U. V.; Ramgir, Niranjan S.; Bhogale, A.; Debnath, A. K.; Muthe, K. P.; Gadkari, S. C.; Kothari, D. C.

    2017-05-01

    The nature of contact between the electrode and the sensing material plays a crucial role in governing the sensing mechanism. Thin films of polyaniline (PANI) and copper-polyaniline nanocomposite (NC) have been deposited at room temperatures by in-situ oxidative polymerization of aniline in the presence of Cu nanoparticles. For sensing applications a thin film Au (gold) ˜100 nm is deposited and used as a conducting electrode. To understand the nature of contact (i.e., ohmic or Schottky) the work function of the conducting polyaniline and nanocomposite films were measured using Kelvin Probe method. I-V characteristics of PANI and NC films investigated at room temperatures further corroborates and confirms the formation of Ohmic contact as evident from work function measurements.

  9. 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

  10. High-coercivity FePt nanoparticle assemblies embedded in silica thin films

    International Nuclear Information System (INIS)

    Yan, Q; Purkayastha, A; Singh, A P; Li, H; Ramanath, G; Li, A; Ramanujan, R V

    2009-01-01

    The ability to process assemblies using thin film techniques in a scalable fashion would be a key to transmuting the assemblies into manufacturable devices. Here, we embed FePt nanoparticle assemblies into a silica thin film by sol-gel processing. Annealing the thin film composite at 650 deg. C transforms the chemically disordered fcc FePt phase into the fct phase, yielding magnetic coercivity values H c >630 mT. The positional order of the particles is retained due to the protection offered by the silica host. Such films with assemblies of high-coercivity magnetic particles are attractive for realizing new types of ultra-high-density data storage devices and magneto-composites.

  11. Intrinsic stress modulation in diamond like carbon films with incorporation of gold nanoparticles by PLA

    Science.gov (United States)

    Panda, Madhusmita; Krishnan, R.; Krishna, Nanda Gopala; Madapu, Kishore K.; Kamruddin, M.

    2018-04-01

    Intrinsic stress modulation in the diamond-like carbon (DLC) coatings with incorporation of gold nanoparticles was studied qualitatively from Raman shift. The films were deposited on Si (1 0 0) substrates by using Pulsed laser ablation (PLA) of pure pyrolytic graphite target and with a gold foil on it. Films compositional and chemical behavior was studied by X-ray photoelectron spectroscopy (XPS) and Visible Raman spectroscopy, respectively. The sp3 content obtained from XPS shows dramatic variation in DLC, DLC-Au(100), DLC-Au(200) and DLC-Au(300) as 39%, 41%, 47% and 66% with various gold contentsas 0%, 12%, 7.3% and 4.7%, respectively. The Raman spectra of DLC/Au films showed G-peak shift towards lower wavenumber indicating the reduction of intrinsic stress (internal compressive stress). The sp2, sp3 fraction in the films are also determined from FWHM (G-Peak).

  12. Mechanical control of the plasmon coupling with Au nanoparticle arrays fixed on the elastomeric film via chemical bond

    Science.gov (United States)

    Bedogni, Elena; Kaneko, Satoshi; Fujii, Shintaro; Kiguchi, Manabu

    2017-03-01

    We have fabricated Au nanoparticle arrays on the flexible poly(dimethylsiloxane) (PDMS) film. The nanoparticles were bound to the film via a covalent bond by a ligand exchange reaction. Thanks to the strong chemical bonding, highly stable and uniformly dispersed Au nanoparticle arrays were fixed on the PDMS film. The Au nanoparticle arrays were characterized by the UV-vis, scanning electron microscope (SEM) and surface enhanced Raman scattering (SERS). The UV-vis and SEM measurements showed the uniformity of the surface-dispersed Au nanoparticles, and SERS measurement confirmed the chemistry of the PDMS film. Reflecting the high stability and the uniformity of the Au nanoparticle arrays, the plasmon wavelength of the Au nanoparticles reversely changed with modulation of the interparticle distance, which was induced by the stretching of the PDMS film. The plasmon wavelength linearly decreased from 664 to 591 nm by stretching of 60%. The plasmon wavelength shift can be explained by the change in the strength of the plasmon coupling which is mechanically controlled by the mechanical strain.

  13. 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

  14. Silver nanoparticle-loaded chitosan-starch based films: Fabrication and evaluation of tensile, barrier and antimicrobial properties

    International Nuclear Information System (INIS)

    Yoksan, Rangrong; Chirachanchai, Suwabun

    2010-01-01

    The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20-25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 μg/mL. The silver nanoparticle-loaded chitosan-starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan-starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications.

  15. The Effect of UV Aging on Antimicrobial and Mechanical Properties of PLA Films with Incorporated Zinc Oxide Nanoparticles.

    Science.gov (United States)

    Mizielińska, Małgorzata; Kowalska, Urszula; Jarosz, Michał; Sumińska, Patrycja; Landercy, Nicolas; Duquesne, Emmanuel

    2018-04-18

    The aim of this study was to examine the influence of accelerated UV-aging on the activity against chosen microorganisms and the mechanical properties of poly-lactic acid (PLA) films enhanced with ZnO nanoparticles. The pure PLA films and tri-layered PLAZnO1%/PLA/PLAZnO1% films of 150 µm thickness were extruded. The samples were treated with UV-A and Q-SUN irradiation. After irradiation the antimicrobial activity and mechanical properties of the films were analyzed. The results of the study demonstrated that PLA films did not inhibit the growth of Staphylococcus aureus , Bacillus cereus , Escherichia coli , Bacillus atrophaeus , and Candida albicans cells. PLA films with incorporated zinc oxide nanoparticles decreased the number of analyzed microorganisms. Accelerated UV aging had no negative effect on the activity of the film containing nano-ZnO against Gram-positive bacteria, but it influenced the activity against Gram-negative cells and C. albicans . Q-SUN irradiation decreased the antimicrobial effect of films with incorporated nanoparticles against B. cereus . UV-A and Q-UV irradiation did not influence the mechanical properties of PLA films containing incorporated ZnO nanoparticles.

  16. Construction of conductive multilayer films of biogenic triangular gold nanoparticles and their application in chemical vapour sensing

    Science.gov (United States)

    Singh, Amit; Chaudhari, Minakshi; Sastry, Murali

    2006-05-01

    Metal nanoparticles are interesting building blocks for realizing films for a number of applications that include bio- and chemical sensing. To date, spherical metal nanoparticles have been used to generate functional electrical coatings. In this paper we demonstrate the synthesis of electrically conductive coatings using biologically prepared gold nanotriangles as the building blocks. The gold nanotriangles are prepared by the reduction of aqueous chloroaurate ions using an extract of the lemongrass plant (Cymbopogon flexuosus) which are thereafter assembled onto a variety of substrates by simple solution casting. The conductivity of the film shows a drastic fall upon mild heat treatment, leading to the formation of electrically conductive thin films of nanoparticles. We have also investigated the possibility of using the gold nanotriangle films in vapour sensing. A large fall in film resistance is observed upon exposure to polar molecules such as methanol, while little change occurs upon exposure to weakly polar molecules such as chloroform.

  17. Formation of electrically conducting, transparent films using silver nanoparticles connected by carbon nanotubes

    International Nuclear Information System (INIS)

    Hwang, Sunna; Noh, Sun Young; Kim, Heesuk; Park, Min; Lee, Hyunjung

    2014-01-01

    To achieve both optical transparency and electrical conductivity simultaneously, we fabricated a single-walled carbon nanotube (SWNT)/silver fiber-based transparent conductive film using silver fibers produced by the electrospinning method. Electrospun silver fibers provided a segregated structure with the silver nanoparticles within the fibrous microstructures as a framework. Additional deposition of SWNT/poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) layers resulted in a remarkable decrease in the surface resistance from very high value (> 3000 kΩ/sq) for the films of electrospun silver fibers, without affecting the optical transmittance at 550 nm. The surface resistance of the SWNT/silver film after the deposition of three layers decreased to 17 Ω/sq with 80% transmittance. Successive depositions of SWNT/PEDOT:PSS layers reduced the surface resistance to 2 Ω/sq without severe loss in optical transmittance (ca. 65%). The transparent conductive films exhibited a performance comparable to that of commercial indium tin oxide films. The individual silver nanoparticles within the electrospun fibers on the substrate were interconnected with SWNTs, which resulted in the efficient activation of a conductive network by bridging the gaps among separate silver nanoparticles. Such a construction of microscopically conductive networks with the minimum use of electrically conductive nanomaterials produced superior electrical conductivity, while maintaining the optical transparency. - Highlights: • Silver fibrous structures were produced by electrospinning method. • SWNTs/PEDOT:PSS was deposited on silver fibrous structures. • These films exhibited a low sheet resistance (∼ 17 Ω/sq) at ∼ 80% optical transparency. • Successive depositions of SWNT/PEDOT:PSS layers reduced the surface resistance to 2 Ω/sq

  18. Synthesis of oxidation resistant lead nanoparticle films by modified pulsed laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Eunsung; Murray, P. Terrence; Subramanyam, Guru; Malik, Hans K.; Schwartz, Kenneth L. [Research Institute, University of Dayton, Dayton, OH 45469-0170 (United States); Research Institute, University of Dayton, Dayton, OH 45469-0170, USA and Graduate Materials Engineering, University of Dayton, Dayton, OH 45469-0240 (United States); Department of Electrical and Computer Engineering, University of Dayton, Dayton, OH 45469-0232 (United States); Northrop Grumman Electronic Systems, Linthicum, MD 21090 (United States)

    2012-07-30

    Thin layers of lead nanoparticles have been produced by a modified pulsed laser ablation (PLA) process in which smaller nanoparticles were swept out of the ablation chamber by a stream of flowing Ar. Large ({mu}m-sized) particles, which are usually deposited during the standard PLA process, were successfully eliminated from the deposit. The nanoparticles deposited on room temperature substrates were well distributed, and the most probable particle diameter was in the order of 30 nm. Since lead is highly reactive, the nanoparticles formed in Ar were quickly oxidized upon exposure to air. A small partial pressure of H{sub 2}S gas was subsequently added to the effluent, downstream from the ablation chamber, and this resulted in the formation of nanoparticle deposits that were surprisingly oxidation resistant. The properties of the nanoparticle films (as determined by transmission electron microscopy, scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and conductivity measurements) are reported, and the mechanism of the oxidation retardation process is discussed.

  19. Superconducting nanowire single photon detectors fabricated from an amorphous Mo{sub 0.75}Ge{sub 0.25} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Verma, V. B.; Lita, A. E.; Vissers, M. R.; Marsili, F.; Pappas, D. P.; Mirin, R. P.; Nam, S. W. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States)

    2014-07-14

    We present the characteristics of superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous Mo{sub 0.75}Ge{sub 0.25} thin-films. Fabricated devices show a saturation of the internal detection efficiency at temperatures below 1 K, with system dark count rates below 500 cps. Operation in a closed-cycle cryocooler at 2.5 K is possible with system detection efficiencies exceeding 20% for SNSPDs which have not been optimized for high detection efficiency. Jitter is observed to vary between 69 ps at 250 mK and 187 ps at 2.5 K using room temperature amplifiers.

  20. Solution-processed copper-nickel nanowire anodes for organic solar cells

    Science.gov (United States)

    Stewart, Ian E.; Rathmell, Aaron R.; Yan, Liang; Ye, Shengrong; Flowers, Patrick F.; You, Wei; Wiley, Benjamin J.

    2014-05-01

    This work describes a process to make anodes for organic solar cells from copper-nickel nanowires with solution-phase processing. Copper nanowire films were coated from solution onto glass and made conductive by dipping them in acetic acid. Acetic acid removes the passivating oxide from the surface of copper nanowires, thereby reducing the contact resistance between nanowires to nearly the same extent as hydrogen annealing. Films of copper nanowires were made as oxidation resistant as silver nanowires under dry and humid conditions by dipping them in an electroless nickel plating solution. Organic solar cells utilizing these completely solution-processed copper-nickel nanowire films exhibited efficiencies of 4.9%.This work describes a process to make anodes for organic solar cells from copper-nickel nanowires with solution-phase processing. Copper nanowire films were coated from solution onto glass and made conductive by dipping them in acetic acid. Acetic acid removes the passivating oxide from the surface of copper nanowires, thereby reducing the contact resistance between nanowires to nearly the same extent as hydrogen annealing. Films of copper nanowires were made as oxidation resistant as silver nanowires under dry and humid conditions by dipping them in an electroless nickel plating solution. Organic solar cells utilizing these completely solution-processed copper-nickel nanowire films exhibited efficiencies of 4.9%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01024h

  1. Fabrication of semi-transparent superoleophobic thin film from fabrics and nanoparticle-based hierarchical structure

    Directory of Open Access Journals (Sweden)

    Nishizawa S.

    2013-08-01

    Full Text Available Superoleophobic thin films have many potential applications including fluid transfer, fluid power systems, stain resistant and antifouling materials, and microfluidics among others. Transparency is also desired with superhydrophobicity for their numerous applications; however transparency and oleophobicity are almost incompatible relationship with each other in the point of surface structure. Because oleophobicity required rougher structure at nano-micro scale than hydrophobicity, and these rough structure brings light scattering. So far, there is very few report of the compatible of transparency and superoleophobicity. In this report, we proposed the see-through type fabrics using the nanoparticle-based hierarchical structure thin film for improving both of oleophobicity and transparency. The vacant space between fibrils of fabrics has two important roles: the one is to through the light, another one is to introduce air layer to realize Cassie state of liquid droplet on thin film. To realize the low surface energy and nanoscale rough structure surface on fibrils, we used the spray method with perfluoroalkyl methacrylic copolymer (PMC, silica nano particles and volatile solvent. From the SEM image, the hierarchical structures of nanoparticle were formed uniformly on the fabrics. The transparency of thin film obtained was approximately 61% and the change of transparency between pre-coated fabrics and coated was 11%. From investigation of the surface wettability, the contact angles of oils (rapeseed oil and hexadecane and water droplet on the fabricated film were over 150 degree.

  2. Metal nanoparticle film-based room temperature Coulomb transistor.

    Science.gov (United States)

    Willing, Svenja; Lehmann, Hauke; Volkmann, Mirjam; Klinke, Christian

    2017-07-01

    Single-electron transistors would represent an approach to developing less power-consuming microelectronic devices if room temperature operation and industry-compatible fabrication were possible. We present a concept based on stripes of small, self-assembled, colloidal, metal nanoparticles on a back-gate device architecture, which leads to well-defined and well-controllable transistor characteristics. This Coulomb transistor has three main advantages. By using the scalable Langmuir-Blodgett method, we combine high-quality chemically synthesized metal nanoparticles with standard lithography techniques. The resulting transistors show on/off ratios above 90%, reliable and sinusoidal Coulomb oscillations, and room temperature operation. Furthermore, this concept allows for versatile tuning of the device properties such as Coulomb energy gap and threshold voltage, as well as period, position, and strength of the oscillations.

  3. Multi-level switching in TiOx Fy film with nanoparticles

    International Nuclear Information System (INIS)

    Sun, Xiangyu; Wu, Chuangui; Shuai, Yao; Pan, Xinqiang; Luo, Wenbo; You, Tiangui; Du, Nan; Schmidt, Heidemarie

    2017-01-01

    A reliable bipolar resistive switching device was achieved with multi-level switching behavior in fluorine-doped titanium oxide (TiO x F y ) film. Different resistance states can be precisely controlled by different pulse voltages, which reveals the device’s high potential in neuromorphic research. The characteristics of I – V curves in each resistance state were analyzed. Nanoparticles were observed in the TiO x F y film by HR-TEM. The underlying physical mechanisms during resistance switching are discussed and a model of a meshy conducting path is proposed. (paper)

  4. Local Fatigue Evaluation in PZT Thin Films with Nanoparticles by Piezoresponse Force Microscopy

    OpenAIRE

    B. S. Li

    2012-01-01

    Lead zirconate titanate (PZT) thin films with the morphotropic phase boundary composition (Zr/Ti = 52/48) have been prepared using a modified diol-based sol-gel route by introducing 1–5 mol% barium titanate (BT) nanoseeds into the precursor solution on platinized silicon substrates (Pt/Ti/SiO2/Si). Macroscopic electric properties of PZT film with nanoparticle showed a significant improvement of ferroelectric properties. This work aims at the systematic study of the local switching polarizatio...

  5. Langmuir-Blodgett films of alkane chalcogenice (S, Se, Te) stabilized gold nanoparticles

    DEFF Research Database (Denmark)

    Brust, M.; Stuhr-Hansen, N.; Norgaard, K.

    2001-01-01

    Gold nanoparticles stabilized by alkanethiolates, alkaneselenides, and alkanetellurides have been prepared by analogous methods. Chloroform solutions of thiolate and selenide stabilized particles were spread and evaporated on the water/air interface where the particles formed well-defined Langmuir...... films. The films were transferred to solid supports of freshly cleaved mica and were studied by atomic force microscopy (AFM). The particles were found to have an average core diameter of 2 nm. The stability of the particles under ambient conditions increased in the order Te

  6. Cu2ZnSnS4 Nanoparticle Absorber Layers for Thin-Film Solar Cells

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin

    or a precursor ink that can be printed, sprayed, or in another way coated on a substrate appropriate for mass production. For CZTS, the power conversion effciency of these device are lagging behind the vacuum processed CZTS thin films, as certain challenges arise with solution-processing. The conversion...... of the as-deposited amorphous or nanocrystalline thin films into an almost "monocrystalline" material is not effective under the current sulfurization conditions. In this work, means have been taken to improve the properties of the nanoparticles in order to make them easier to handle and better...

  7. TiO2-Anatase Nanowire Dispersed Composite Electrode for Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Asagoe, K; Suzuki, Y; Ngamsinlapasathian, S; Yoshikawa, S

    2007-01-01

    TiO 2 anatase nanowires have been prepared by a hydrothermal process followed by post-heat treatment in air. TiO 2 nanoparticle/TiO 2 nanowire composite electrodes were prepared for dye-sensitized solar cells (DSC) in order to improve light-to-electricity conversion efficiency. The TiO 2 NP/TiO 2 NW composite cells showed higher DSC performance than ordinary nanoparticle cells and fully nanowire cells: efficiency (η = 6.53 % for DSC with 10% nanowire, whereas 5.59% for 0% nanowire, and 2.42% for 100% nanowire

  8. The Self- and Directed Assembly of Nanowires

    Science.gov (United States)

    Smith, Benjamin David

    This thesis explores the self- and directed assembly of nanowires. Specifically, we examine the driving forces behind nanowire self-assembly and the macro-structures that are formed. Particle-dense, oriented nanowire structures show promise in the fields of photonics, energy, sensing, catalysis, and electronics. Arrays of spherical particles have already found uses in electronic inks, sensing arrays, and many other commercial applications; but, it is a challenge to create specific arrays of morphologically and/or compositionally anisotropic particles. The following chapters illuminate the interactions that drive the assembly of anisotropic particles in high density solutions in the absence of applied fields or solution drying. Special emphasis is placed on the structures that are formed. The properties of micro- and nanoparticles and their assembly are introduced in Chapter 1. In particular, the properties of shape and material anisotropic particles are highlighted, while challenges in producing desired arrays are discussed. In this thesis, metallic nanowires of increasing complexity were used to examine the self-assembly behavior of both shape and material anisotropic particles. Nanowires were synthesized through templated electrodeposition. In this process, porous alumina membranes served as a template in which metal salts were reduced to form particles. Upon template dissolution, billions of nominally identical particles were released. We specifically focused on segmented, metallic nanowires 2-13 mum in length and 180 to 350 nm in diameter. Since these particles have strong van der Waals (VDWs) attractions, an electrostatically repulsive coating was necessary to prevent aggregation; we used small molecule, DNA, or amorphous silica coatings. Nanowires and their coatings were characterized by electron microscopy. In order to study self-assembly behavior, particle-dense aqueous suspensions were placed within an assembly chamber defined by a silicone spacer. The

  9. The Effects of SiO2 Nanoparticles on Mechanical and Physicochemical Properties of Potato Starch Films

    Directory of Open Access Journals (Sweden)

    Z. Torabi

    2013-06-01

    Full Text Available In this paper effect of SiO2 nanoparticles was investigated on potato starch films. Potato starch films were prepared by casting method with addition of nano-silicon dioxide and a mixture of sorbitol/glycerol (weight ratio of 3 to 1 as plasticizers. SiO2 nanoparticles incorporated to the potato starch films at different concentrations 0, 1, 2, 3, and 5% of total solid, and the films were dried under controlled conditions.  Physicochemical properties such as water absorption capacity (WAC, water vapor permeability (WVP and mechanical properties of the films were measured. Results show that by increasing the concentration of silicon dioxide nanoparticles, mechanical properties of films can be improved. Also incorporation of silicon dioxide nanoparticles in the structure of biopolymer decrease permeability of the gaseous molecules such as water vapor. In summary, addition of silicon dioxide nanoparticles improves functional properties of potato starch films and these bio Nano composites can be used in food packaging.

  10. Highly Conductive Cu 2– x S Nanoparticle Films through Room-Temperature Processing and an Order of Magnitude Enhancement of Conductivity via Electrophoretic Deposition

    KAUST Repository

    Otelaja, Obafemi O.; Ha, Don-Hyung; Ly, Tiffany; Zhang, Haitao; Robinson, Richard D.

    2014-01-01

    © 2014 American Chemical Society. A facile room-temperature method for assembling colloidal copper sulfide (Cu2-xS) nanoparticles into highly electrically conducting films is presented. Ammonium sulfide is utilized for connecting the nanoparticles

  11. Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting

    Directory of Open Access Journals (Sweden)

    Sun-Kyu Lee

    2017-05-01

    Full Text Available We propose a nanofabrication process to generate large-area arrays of noble metal nanoparticles on glass substrates via nanoimprinting and dewetting of metallic thin films. Glass templates were made via pattern transfer from a topographic Si mold to an inorganically cross-linked sol–gel (IGSG resist on glass using a two-layer polydimethylsiloxane (PDMS stamp followed by annealing, which turned the imprinted resist into pure silica. The transparent, topographic glass successfully templated the assembly of Au and Ag nanoparticle arrays via thin-film deposition and dewetting at elevated temperatures. The microstructural and mechanical characteristics that developed during the processes were discussed. The results are promising for low-cost mass fabrication of devices for several photonic applications.

  12. Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting.

    Science.gov (United States)

    Lee, Sun-Kyu; Hwang, Sori; Kim, Yoon-Kee; Oh, Yong-Jun

    2017-01-01

    We propose a nanofabrication process to generate large-area arrays of noble metal nanoparticles on glass substrates via nanoimprinting and dewetting of metallic thin films. Glass templates were made via pattern transfer from a topographic Si mold to an inorganically cross-linked sol-gel (IGSG) resist on glass using a two-layer polydimethylsiloxane (PDMS) stamp followed by annealing, which turned the imprinted resist into pure silica. The transparent, topographic glass successfully templated the assembly of Au and Ag nanoparticle arrays via thin-film deposition and dewetting at elevated temperatures. The microstructural and mechanical characteristics that developed during the processes were discussed. The results are promising for low-cost mass fabrication of devices for several photonic applications.

  13. Organic Nanowires

    DEFF Research Database (Denmark)

    Balzer, Frank; Schiek, Manuela; Al-Shamery, Katharina

    Single crystalline nanowires from fluorescing organic molecules like para-phenylenes or thiophenes are supposed to become key elements in future integrated optoelectronic devices [1]. For a sophisticated design of devices based on nanowires the basic principles of the nanowire formation have...... atomic force microscopy and from polarized far-field optical microscopy for various prototypical molecules are reproduced by electrostatic and Monte Carlo calculations. Based on the crystal structure, predictions on the growth habit from other conjugated molecules become in reach....

  14. Synthesis of Oxidation-Resistant Cupronickel Nanowires for Transparent Conducting Nanowire Networks

    Energy Technology Data Exchange (ETDEWEB)

    Rathmall, Aaron [Duke University; Nguyen, Minh [Duke University; Wiley, Benjamin J [Duke University

    2012-01-01

    Nanowires of copper can be coated from liquids to create flexible, transparent conducting films that can potentially replace the dominant transparent conductor, indium tin oxide, in displays, solar cells, organic light-emitting diodes, and electrochromic windows. One issue with these nanowire films is that copper is prone to oxidation. It was hypothesized that the resistance to oxidation could be improved by coating copper nanowires with nickel. This work demonstrates a method for synthesizing copper nanowires with nickel shells as well as the properties of cupronickel nanowires in transparent conducting films. Time- and temperature-dependent sheet resistance measurements indicate that the sheet resistance of copper and silver nanowire films will double after 3 and 36 months at room temperature, respectively. In contrast, the sheet resistance of cupronickel nanowires containing 20 mol % nickel will double in about 400 years. Coating copper nanowires to a ratio of 2:1 Cu:Ni gave them a neutral gray color, making them more suitable for use in displays and electrochromic windows. These properties, and the fact that copper and nickel are 1000 times more abundant than indium or silver, make cupronickel nanowires a promising alternative for the sustainable, efficient production of transparent conductors.

  15. Synthesis and Characterization of BSA Conjugated Silver Nanoparticles (Ag/BSA Nanoparticles) and Evaluation of Biological Properties of Ag/BSA Nanoparticles and Ag/BSA Nanoparticles Loaded Poly(hydroxy butyrate valerate) PHBV Films

    Science.gov (United States)

    Ambaye, Almaz

    Ag/BSA nanoparticles was found to be in a range of 9-13 nm. X-ray photo electron spectroscopy measurements of argon sputtered Ag/BSA nanoparticles provided evidence that the outer and inner region of nanoparticles are mainly composed of BSA and silver, respectively. Having characterized the nanoparticles, the next phase of the study was to evaluate the antibacterial activity and cytotoxicity level of BSA stabilized silver nanoparticles. The antibacterial efficacy of Ag/BSA nanoparticles against E. coli and S. aureus was evaluated, and minimum lethal concentration was found to be 2ppm and 7ppm, respectively. E. coli showed a higher susceptibility to silver nanoparticles than S. aureus, which could be attributed to the difference in the cell wall structure. We have also investigated the cytotoxicity level of Ag/BSA nanoparticles towards MC3T3-E1 osteoblast cells. The minimum bactericidal concentration found for both strains is lower than the silver nanoparticles concentration that was toxic to the osteoblast cells. Preliminary studies of Ag/BSA nanoparticles loaded collagen immobilized PHBV film showed that the Ag/BSA nanoparticles loaded PHBV film inhibit bacterial growth. The findings of our study can be extremely useful in the design of novel scaffold to address the critical needs of bone tissue engineering community.

  16. Brush-Coated Nanoparticle Polymer Thin Films: structure-mechanical-optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter F. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

    2014-08-15

    Our work was devoted to understanding the structure and properties of a class of thin film polymer nanocomposites (PNCs). PNCs are composed of polymer hosts into which nanoparticles (metallic nanoparticles, quantum dots, nanorods, C60, nanotubes) are incorporated. PNCs exhibit a diverse range of functional properties (optical, electronic, mechanical, biomedical, structural), determined in part by the chemical composition of the polymer host and the type of nanoparticle. The properties PNCs rely not only on specific functional, size-dependent, behavior of the nanoparticles, but also on the dispersion, and organizational order in some cases, inter-nanoparticle separation distances, and on relative interactions between the nanoparticles and the host. Therefore the scientific challenges associated with understanding the interrelations between the structure and function/properties of PNCs are far more complex than may be understood based only on the knowledge of the compositions of the constituents. The challenges of understanding the structure-function behavior of PNCs are further compounded by the fact that control of the dispersion of the nanoparticles within the polymer hosts is difficult; one must learn how to disperse inorganic particles within an organic host. The goal of this proposal was to develop an understanding of the connection between the structure and the thermal (glass transition), mechanical and optical properties of a specific class of PNCs. Specifically PNCs composed of polymer chain grafted gold nanoparticles within polymer hosts. A major objective was to understand how to develop basic principles that enable the fabrication of functional materials possessing optimized morphologies and combinations of materials properties.

  17. Locally formation of Ag nanoparticles in chalcogenide phase change thin films induced by nanosecond laser pulses

    International Nuclear Information System (INIS)

    Huang, Huan; Zhang, Lei; Wang, Yang; Han, Xiaodong; Wu, Yiqun; Zhang, Ze; Gan, Fuxi

    2012-01-01

    A simple method to optically synthesize Ag nanoparticles in Ge 2 Sb 2 Te 5 phase change matrix is described. The fine structures of the locally formed phase change chalcogenide nanocomposite are characterized by high-resolution transmission electron microscopy. The formation mechanism of the nanocomposite is discussed with temperature evolution and distribution simulations. This easy-prepared metal nano-particle-embedded phase change microstructure will have great potential in nanophotonics applications, such as for plasmonic functional structures. This also provides a generalized approach to the preparation of well-dispersed nanoparticle-embedded composite thin films in principle. -- Highlights: ► We describe a method to prepare chalcogenide microstructures with Ag nanoparticles. ► We give the fine structural images of phase change nanocomposites. ► We discuss the laser-induced fusion mechanism by temperature simulation. ► This microstructure will have great potential in nanophotonics applications.

  18. Deposition of Polymer Thin Films on ZnO Nanoparticles by a Plasma Treatment

    Science.gov (United States)

    2001-11-01

    exchange for removing metal ions frori water. If on the surface of these nanoparticles, an extremely thin layer of polyacrylic filr can be coated by a...plasma treatment. The polyacrylic film will react with metallic ions in water. As a result of the high surface-to-volume ratio of these narioparticles, the...experiments performed on a JEM 2010F. In FFIR experiment, potassium bromide(KBr) of 99%+ purity was obtained from Aldrich Chemical Company Inc

  19. Improved diode performance of Ag nanoparticle dispersed Er doped In2O3 film

    Science.gov (United States)

    Ghosh, Anupam; Dwivedi, Shyam Murli Manohar Dhar; Chakrabartty, Shubhro; Mondal, Aniruddha

    2018-04-01

    Ag nanoparticle(NP) dispersedEr doped In2O3 film was prepared by sol-gel method followed by thermal evaporation cum glancing angle deposition technique. The Schottky contact based devicecontaining Ag NPs shows ideality factor of ˜180 at 10 K and ˜5 at 300 K, which is lesser as compared to the device that does not contain Ag NPs. The lower ideality factor value all over the temperature range makes the diode more reliable.

  20. In situ AFM analysis investigating disassembly of DNA nanoparticles and nano-films.

    Science.gov (United States)

    Zou, Yi; Wan, Lei; Blacklock, Jenifer; Oupicky, David; Mao, Guangzhao

    2013-01-01

    Synthetic vector-based gene delivery systems continue to gain strength as viable alternatives to viral vectors due to safety and other concerns. DNA release dynamics is key to the understanding and control of gene delivery from nano-systems. Here we describe atomic force microscope application to the understanding of DNA release dynamics from bioreducible polycation-based nano-systems. The two nano-systems are polyplex nanoparticles and layer-by-layer films.

  1. Solution synthesis of mixed-metal chalcogenide nanoparticles and spray deposition of precursor films

    Science.gov (United States)

    Schulz, Douglas L.; Curtis, Calvin J.; Ginley, David S.

    2000-01-01

    A colloidal suspension comprising metal chalcogenide nanoparticles and a volatile capping agent. The colloidal suspension is made by reacting a metal salt with a chalcogenide salt in an organic solvent to precipitate a metal chalcogenide, recovering the metal chalcogenide, and admixing the metal chalcogenide with a volatile capping agent. The colloidal suspension is spray deposited onto a substrate to produce a semiconductor precursor film which is substantially free of impurities.

  2. Cassava starch films containing acetylated starch nanoparticles as reinforcement: Physical and mechanical characterization.

    Science.gov (United States)

    Teodoro, Ana Paula; Mali, Suzana; Romero, Natália; de Carvalho, Gizilene Maria

    2015-08-01

    This paper reports the use of acetylated starch nanoparticles (NPAac) as reinforcement in thermoplastic starch films. NPAac with an average size of approximately 500 nm were obtained by nanoprecipitation. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) indicated that NPAac are more thermally stable and essentially amorphous when compared with acetylated starch. Thermoplastic starch films with different proportions of NPAac (0.5, 1.0, 1.5, 10.0%, w/w) were obtained and characterized by scanning electron microscopy (SEM), water vapor permeability (WVP), adsorption isotherms, TGA and mechanical tests. The inclusion of reinforcement caused changes in film properties: WVP was lowered by 41% for film with 1.5% (w/w) of NPAac and moisture adsorption by 33% for film with 10% (w/w) of NPAac; and the Young's modulus and thermal stability were increased by 162% and 15%, respectively, for film with 0.5% (w/w) of NPAac compared to the starch film without the addition of NPAac. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. The role of polymer films on the oxidation of magnetite nanoparticles

    Science.gov (United States)

    Letti, C. J.; Paterno, L. G.; Pereira-da-Silva, M. A.; Morais, P. C.; Soler, M. A. G.

    2017-02-01

    A detailed investigation about the role of polymer films on the oxidation process of magnetite nanoparticles (∼7 nm diameter), under laser irradiation is performed employing micro Raman spectroscopy. To support this investigation, Fe3O4-np are synthesized by the co-precipitation method and assembled layer-by-layer with sodium sulfonated polystyrene (PSS). Polymer films (Fe3O4-np/PSS)n with n=2,3,5,7,10 and 25 bilayers are employed as a model system to study the oxidation process under laser irradiation. Raman data are further processed by principal component analysis. Our findings suggest that PSS protects Fe3O4-np from oxidation when compared to powder samples, even for the sample with the greater number of bilayers. Further, the oxidation of magnetite to maghemite occurs preferably for thinner films up to 7 bilayers, while the onset for the formation of the hematite phase depends on the laser intensity for thicker films. Water takes part on the oxidation processes of magnetite, the oxidation/phase transformation of Fe3O4-np is intensified in films with more bilayers, since more water is included in those films. Encapsulation of Fe3O4-np by PSS in layer-by-layer films showed to be very efficient to avoid the oxidation process in nanosized magnetite.

  4. Single-Nanoparticle Photoelectrochemistry at a Nanoparticulate TiO2 -Filmed Ultramicroelectrode.

    Science.gov (United States)

    Peng, Yue-Yi; Ma, Hui; Ma, Wei; Long, Yi-Tao; Tian, He

    2018-03-26

    An ultrasensitive photoelectrochemical method for achieving real-time detection of single nanoparticle collision events is presented. Using a micrometer-thick nanoparticulate TiO 2 -filmed Au ultra-microelectrode (TiO 2 @Au UME), a sub-millisecond photocurrent transient was observed for an individual N719-tagged TiO 2 (N719@TiO 2 ) nanoparticle and is due to the instantaneous collision process. Owing to a trap-limited electron diffusion process as the rate-limiting step, a random three-dimensional diffusion model was developed to simulate electron transport dynamics in TiO 2 film. The combination of theoretical simulation and high-resolution photocurrent measurement allow electron-transfer information of a single N719@TiO 2 nanoparticle to be quantified at single-molecule accuracy and the electron diffusivity and the electron-collection efficiency of TiO 2 @Au UME to be estimated. This method provides a test for studies of photoinduced electron transfer at the single-nanoparticle level. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Spray-coated ligand-free Cu2ZnSnS4 nanoparticle thin films

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Murthy, Swathi; Kofod, Guggi

    We have fabricated Cu2ZnSnS4 (CZTS) thin films from spray-coating ligand-free nanoparticle inks. The as-synthesized CZTS nanoparticles were inherently ligand-free [1], which allows the use of polar solvents, such as water and ethanol. Another advantage of these particles is that user- and environ......We have fabricated Cu2ZnSnS4 (CZTS) thin films from spray-coating ligand-free nanoparticle inks. The as-synthesized CZTS nanoparticles were inherently ligand-free [1], which allows the use of polar solvents, such as water and ethanol. Another advantage of these particles is that user......- and environmentally-friendly alkali metal chloride salts can be directly dissolved in controllable amounts. The homogeneous distribution of alkali metals in the ink allows uniform grain growth within the deposited absorber layer as a result of liquid phase assisted sintering. We find that particularly beneficial...... as an unquantifiable amount of ZnS. A Sono-tek spray-coating system is used which utilizes ultrasonic atomization. We investigate the effect of different binders, ink concentration, and spray-coating conditions, i.e. spray power, flow rate from syringe pump, distance between spray nozzle and the substrate, and time...

  6. Optical and photoelectrical studies of gold nanoparticle-decorated C{sub 60} films

    Energy Technology Data Exchange (ETDEWEB)

    Dmitruk, N.L., E-mail: dmitruk@isp.kiev.u [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Borkovskaya, O.Yu.; Mamykin, S.V.; Naumenko, D.O. [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Meza-Laguna, V. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior, Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Basiuk Golovataya-Dzhymbeeva, E.V. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico (UNAM), Circuito exterior S/N Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Lee, I. Puente [Facultad de Quimica, UNAM, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2010-01-01

    Optical and photoelectrical studies were performed on octane-1,8-dithiol cross-linked fullerene films, with supported gold nanoparticles (C{sub 60}-DT-Au). According to high-resolution transmission electron microscopy observations, the average size of obtained gold nanoparticles was about 5 nm, and the shape was spherical. The comparative investigation of optical properties of pristine and cross-linked with octane-1,8-dithiol C{sub 60} films, decorated with gold nanoparticles, found the difference in the extinction coefficient spectra, which was observed also in the photocurrent spectra of barrier heterostructure Au/C{sub 60}/Si. The analysis of dark current-voltage characteristics for Au/C{sub 60}/Si heterostructures showed that the model for them includes the barrier at the C{sub 60}/Si interface and internal barriers in the C{sub 60} layer, caused by the trapping centers. The hopping mechanism of the current transport in the C{sub 60} layer was supplemented with the Poole-Frenkel emission process on these centers, with the barrier height greater for the fullerene C{sub 60} film cross-linked with octane-1,8-dithiol.

  7. Nanocomposite films containing Au nanoparticles formed by electrochemical reduction of metal ions in the multilayer films as electrocatalyst for dioxygen reduction

    International Nuclear Information System (INIS)

    Huang Minghua; Shen Yan; Cheng Wenlong; Shao Yong; Sun Xuping; Liu Baifeng; Dong Shaojun

    2005-01-01

    Through electrostatic layer-by-layer assembly, AuCl 4 - anions and [tetrakis(N-methylpyridyl)porphyrinato] cobalt (CoTMPyP) cations were alternately deposited on indium tin oxide (ITO) substrates, and 4-aminobenzoic acid modified glassy carbon electrode. Electrochemical reduction of AuCl 4 - anions sandwiched between CoTMPyP layers leads to the in situ formation of Au nanoparticles in the multilayer films. Regular growth of the multilayer films is monitored by UV-vis spectroscopy. UV-vis spectroscopy, X-ray photoelectron spectroscopy and cyclic voltammetry confirm the formation of Au nanoparticles in the multilayer films after electrochemical reduction of AuCl 4 - anions. Atomic force spectroscopy verifies that the as-prepared Au nanoparticles are uniformly distributed with average particles diameters of 20-25 nm. The resulting composite films containing Au nanoparticles with high stability exhibit high electrocatalytic activity for the reduction of dioxygen. Rotating disk electrode voltammetry and rotating ring-disk electrode voltammetry demonstrate the Au nanoparticles-containing films can catalyze two-electron reduction of O 2 to H 2 O 2 in O 2 -saturated 0.1 M H 2 SO 4 solution

  8. Electron Microscopy Characterization of Vanadium Dioxide Thin Films and Nanoparticles

    Science.gov (United States)

    Rivera, Felipe

    Vanadium dioxide (VO_2) is a material of particular interest due to its exhibited metal to insulator phase transition at 68°C that is accompanied by an abrupt and significant change in its electronic and optical properties. Since this material can exhibit a reversible drop in resistivity of up to five orders of magnitude and a reversible drop in infrared optical transmission of up to 80%, this material holds promise in several technological applications. Solid phase crystallization of VO_2 thin films was obtained by a post-deposition annealing process of a VO_{x,x approx 2} amorphous film sputtered on an amorphous silicon dioxide (SiO_2) layer. Scanning electron microscopy (SEM) and electron-backscattered diffraction (EBSD) were utilized to study the morphology of the solid phase crystallization that resulted from this post-deposition annealing process. The annealing parameters ranged in temperature from 300°C up to 1000°C and in time from 5 minutes up to 12 hours. Depending on the annealing parameters, EBSD showed that this process yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. In addition to these films on SiO_2, other VO_2 thin films were deposited onto a-, c-, and r-cuts of sapphire and on TiO_2(001) heated single-crystal substrates by pulsed-laser deposition (PLD). The temperature of the substrates was kept at ˜500°C during deposition. EBSD maps and orientation imaging microscopy were used to study the epitaxy and orientation of the VO_2 grains deposited on the single crystal substrates, as well as on the amorphous SiO_2 layer. The EBSD/OIM results showed that: 1) For all the sapphire substrates analyzed, there is a predominant family of crystallographic relationships wherein the rutile VO_2{001} planes tend to lie parallel to the sapphire's {10-10} and the rutile VO_2{100} planes lie parallel to the sapphire's {1-210} and {0001}. Furthermore, while this family of

  9. CZTS nanoparticle absorber layer for thin film solar cells

    DEFF Research Database (Denmark)

    Symonowicz, Joanna; Jensen, Kirsten M. Ørnsbjerg; Engberg, Sara Lena Josefin

    a pure CZTS kesterite phase without secondary phases as they result in structural inhomogeneity, local fluctuation of open circuit voltage and high carrier recombination [3]. This leads to poor device performance and repeatability issues. Here, we present how the synthesis parameters affect the resulting...... CZTS nanoparticles. The product is characterized by XRD, EDS, and Raman spectroscopy in order to fully detect possible secondary phases and characterize the CZTS phase. By combining Rietveld refinement of the XRD data with X-ray total scattering with PDF analysis, the nanoscale atomic structure...

  10. Enhanced photoelectrocatalytic performance of α-Fe2O3 thin films by surface plasmon resonance of Au nanoparticles coupled with surface passivation by atom layer deposition of Al2O3.

    Science.gov (United States)

    Liu, Yuting; Xu, Zhen; Yin, Min; Fan, Haowen; Cheng, Weijie; Lu, Linfeng; Song, Ye; Ma, Jing; Zhu, Xufei

    2015-12-01

    The short lifetime of photogenerated charge carriers of hematite (α-Fe2O3) thin films strongly hindered the PEC performances. Herein, α-Fe2O3 thin films with surface nanowire were synthesized by electrodeposition and post annealing method for photoelectrocatalytic (PEC) water splitting. The thickness of the α-Fe2O3 films can be precisely controlled by adjusting the duration of the electrodeposition. The Au nanoparticles (NPs) and Al2O3 shell by atom layer deposition were further introduced to modify the photoelectrodes. Different constructions were made with different deposition orders of Au and Al2O3 on Fe2O3 films. The Fe2O3-Au-Al2O3 construction shows the best PEC performance with 1.78 times enhancement by localized surface plasmon resonance (LSPR) of NPs in conjunction with surface passivation of Al2O3 shells. Numerical simulation was carried out to investigate the promotion mechanisms. The high PEC performance for Fe2O3-Au-Al2O3 construction electrode could be attributed to the Al2O3 intensified LSPR, effective surface passivation by Al2O3 coating, and the efficient charge transfer due to the Fe2O3-Au Schottky junctions.

  11. Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

    Directory of Open Access Journals (Sweden)

    A. O. Kucherik

    2017-01-01

    Full Text Available Moving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology.

  12. Uniform thin films of TiO2 nanoparticles deposited by matrix-assisted pulsed laser evaporation

    International Nuclear Information System (INIS)

    Caricato, A.P.; Manera, M.G.; Martino, M.; Rella, R.; Romano, F.; Spadavecchia, J.; Tunno, T.; Valerini, D.

    2007-01-01

    We report morphological and optical properties of a colloidal TiO 2 nanoparticle film, deposited on a quartz substrate by using the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. Atomic Force Microscopy demonstrated that a good uniformity of the deposition can be obtained. The presence of agglomerates with dimensions of about 1 μm in size was noticed. Form UV-vis transmission spectra, recorded in the 200-800 nm range, the optical constants and the energy gap were determined besides the film thickness. The optical constants resulted in agreement with the values reported in literature for TiO 2 nanoparticle thin films

  13. Hybrid chitosan–Pluronic F-127 films with BaTiO3:Co nanoparticles: Synthesis and properties

    International Nuclear Information System (INIS)

    Fuentes, S.; Dubo, J.; Barraza, N.; González, R.; Veloso, E.

    2015-01-01

    In this study, magnetic BaTiO 3 :Co (BT:Co) nanoparticles prepared using a combined sol–gel–hydrothermal technique were dispersed in a chitosan/Pluronic F-127 solution (QO/Pl) to obtain a nanocomposite hybrid films. Nanoparticles and hybrid films were characterized by X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and alternating gradient magnetometry (AGM). Experimental results indicated that the BT:Co nanoparticles were encapsulated in the QO/Pl hybrid films and that the magnetic properties of the QO/Pl/BT:Co nanocomposites are similar to the naked BT:Co nanoparticles. Results indicate that Co doping produces an enhancement in the ferromagnetic behavior of the BT nanoparticle. The coating restricts this enhancement only to low-fields, leaving the diamagnetic behavior of BT at high-fields. Magnetically stable sizes (PSD) were obtained at 3% Co doping for both naked nanoparticles and hybrid films. These show an increased magnetic memory capacity and a softer magnetic hardness with respect to non-doped BT nanoparticles. - Highlights: • We described the synthesis of magnetic BaTiO 3 :Co dispersed in chitosan (QO)/Pluronic F-127 (Pl) solution by sonication to obtain nanocomposite hybrid films. • We describe the physical and magnetic properties of BaTiO 3 :Co nanoparticles and QO/Pl/BT:Co hybrid films. • The magnetic properties are defines by the presence of magnetic domains. These magnetic domains are close related with the amount of Co in the host lattice. • The prepared phases could be considered as multifunctional materials, with magnetic and ferri-electrical properties, with potential uses in the design of devices

  14. Hybrid chitosan–Pluronic F-127 films with BaTiO{sub 3}:Co nanoparticles: Synthesis and properties

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, S., E-mail: sfuentes@ucn.cl [Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Santiago (Chile); Dubo, J. [Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Barraza, N. [Departamento de Física, Facultad de Ciencias, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); González, R. [Laboratorio de Magnetismo, Departamento de Ciencias Geológicas, Universidad Católica del Norte, Antofagasta (Chile); Veloso, E. [Dirección de Investigaciones Científicas y Tecnológicas, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Santiago (Chile)

    2015-03-01

    In this study, magnetic BaTiO{sub 3}:Co (BT:Co) nanoparticles prepared using a combined sol–gel–hydrothermal technique were dispersed in a chitosan/Pluronic F-127 solution (QO/Pl) to obtain a nanocomposite hybrid films. Nanoparticles and hybrid films were characterized by X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and alternating gradient magnetometry (AGM). Experimental results indicated that the BT:Co nanoparticles were encapsulated in the QO/Pl hybrid films and that the magnetic properties of the QO/Pl/BT:Co nanocomposites are similar to the naked BT:Co nanoparticles. Results indicate that Co doping produces an enhancement in the ferromagnetic behavior of the BT nanoparticle. The coating restricts this enhancement only to low-fields, leaving the diamagnetic behavior of BT at high-fields. Magnetically stable sizes (PSD) were obtained at 3% Co doping for both naked nanoparticles and hybrid films. These show an increased magnetic memory capacity and a softer magnetic hardness with respect to non-doped BT nanoparticles. - Highlights: • We described the synthesis of magnetic BaTiO{sub 3}:Co dispersed in chitosan (QO)/Pluronic F-127 (Pl) solution by sonication to obtain nanocomposite hybrid films. • We describe the physical and magnetic properties of BaTiO{sub 3}:Co nanoparticles and QO/Pl/BT:Co hybrid films. • The magnetic properties are defines by the presence of magnetic domains. These magnetic domains are close related with the amount of Co in the host lattice. • The prepared phases could be considered as multifunctional materials, with magnetic and ferri-electrical properties, with potential uses in the design of devices.

  15. Thermal Vapor Deposition and Characterization of Polymer-Ceramic Nanoparticle Thin Films and Capacitors

    Science.gov (United States)

    Iwagoshi, Joel A.

    Research on alternative energies has become an area of increased interest due to economic and environmental concerns. Green energy sources, such as ocean, wind, and solar power, are subject to predictable and unpredictable generation intermittencies which cause instability in the electrical grid. This problem could be solved through the use of short term energy storage devices. Capacitors made from composite polymer:nanoparticle thin films have been shown to be an economically viable option. Through thermal vapor deposition, we fabricated dielectric thin films composed of the polymer polyvinylidine fluoride (PVDF) and the ceramic nanoparticle titanium dioxide (TiO2). Fully understanding the deposition process required an investigation of electrode and dielectric film deposition. Film composition can be controlled by the mass ratio of PVDF:TiO2 prior to deposition. An analysis of the relationship between the ratio of PVDF:TiO2 before and after deposition will improve our understanding of this novel deposition method. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy were used to analyze film atomic concentrations. The results indicate a broad distribution of deposited TiO2 concentrations with the highest deposited amount at an initial mass concentration of 17% TiO2. The nanoparticle dispersion throughout the film is analyzed through atomic force microscopy and energy dispersive x-ray spectroscopy. Images from these two techniques confirm uniform TiO2 dispersion with cluster size less than 300 nm. These results, combined with spectroscopic analysis, verify control over the deposition process. Capacitors were fabricated using gold parallel plates with PVDF:TiO 2 dielectrics. These capacitors were analyzed using the atomic force microscope and a capacohmeter. Atomic force microscope images confirm that our gold films are acceptably smooth. Preliminary capacohmeter measurements indicate capacitance values of 6 nF and break down voltages of 2.4 V

  16. Growth of ordered silver nanoparticles in silica film mesostructured with a triblock copolymer PEO-PPO-PEO

    International Nuclear Information System (INIS)

    Bois, L.; Chassagneux, F.; Parola, S.; Bessueille, F.; Battie, Y.; Destouches, N.; Boukenter, A.; Moncoffre, N.; Toulhoat, N.

    2009-01-01

    Elaboration of mesostructured silica films with a triblock copolymer polyethylene oxide-polypropylene oxide-polyethylene oxide, (PEO-PPO-PEO) and controlled growth of silver nanoparticles in the mesostructure are described. The films are characterized using UV-visible optical absorption spectroscopy, TEM, AFM, SEM, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Organized arrays of spherical silver nanoparticles with diameter between 5 and 8 nm have been obtained by NaBH 4 reduction. The size and the repartition of silver nanoparticles are controlled by the film mesostructure. The localization of silver nanoparticles exclusively in the upper-side part of the silica-block copolymer film is evidenced by RBS experiment. On the other hand, by using a thermal method, 40 nm long silver sticks can be obtained, by diffusion and coalescence of spherical particles in the silica-block copolymer layer. In this case, migration of silver particles toward the glass substrate-film interface is shown by the RBS experiment. - Graphical abstract: Growth of silver nanoparticles in a mesostructured block copolymer F127-silica film is performed either by a chemical route involving NaBH 4 reduction or by a thermal method. An array of spherical silver nanoparticles with 10 nm diameter on the upper-side of the mesostructured film or silver sticks long of 40 nm with a preferential orientation are obtained according to the method used. a: TEM image of the Fag5SiNB sample illustrating the silver nanoparticles array obtained by the chemical process; b: HR-TEM image of the Fag20Sid2 sample illustrating the silver nanosticks obtained by the thermal process.

  17. POLYMER COMPOSITE FILMS WITH SIZE-SELECTED METAL NANOPARTICLES FABRICATED BY CLUSTER BEAM TECHNIQUE

    DEFF Research Database (Denmark)

    Ceynowa, F. A.; Chirumamilla, Manohar; Popok, Vladimir

    2017-01-01

    Formation of polymer films with size-selected silver and copper nanoparticles (NPs) is studied. Polymers are prepared by spin coating while NPs are fabricated and deposited utilizing a magnetron sputtering cluster apparatus. The particle embedding into the films is provided by thermal annealing...... after the deposition. The degree of immersion can be controlled by the annealing temperature and time. Together with control of cluster coverage the described approach represents an efficient method for the synthesis of thin polymer composite layers with either partially or fully embedded metal NPs....... Combining electron beam lithography, cluster beam deposition and thermal annealing allows to form ordered arrays of metal NPs on polymer films. Plasticity and flexibility of polymer host and specific properties added by coinage metal NPs open a way for different applications of such composite materials...

  18. Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

    Science.gov (United States)

    Schlicke, Hendrik; Schröder, Jan H.; Trebbin, Martin; Petrov, Alexey; Ijeh, Michael; Weller, Horst; Vossmeyer, Tobias

    2011-07-01

    A new, extremely efficient method for the fabrication of films comprised of gold nanoparticles (GNPs) crosslinked by organic dithiols is presented in this paper. The method is based on layer-by-layer spin-coating of both components, GNPs and crosslinker, and enables the deposition of films several tens of nanometers in thickness within a few minutes. X-ray diffraction and conductance measurements reveal the proper adjustment concentration of the crosslinker solution of the critical is in order to prevent the destabilization and coalescence of particles. UV/vis spectroscopy, atomic force microscopy, and conductivity measurements indicate that films prepared via layer-by-layer spin-coating are of comparable quality to coatings prepared via laborious layer-by-layer self-assembly using immersion baths. Because spin-coated films are not bound chemically to the substrate, they can be lifted-off by alkaline underetching and transferred onto 3d-electrodes to produce electrically addressable, freely suspended films. Comparative measurements of the sheet resistances indicate that the transfer process does not compromise the film quality.

  19. Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

    International Nuclear Information System (INIS)

    Schlicke, Hendrik; Schroeder, Jan H; Trebbin, Martin; Petrov, Alexey; Ijeh, Michael; Weller, Horst; Vossmeyer, Tobias

    2011-01-01

    A new, extremely efficient method for the fabrication of films comprised of gold nanoparticles (GNPs) crosslinked by organic dithiols is presented in this paper. The method is based on layer-by-layer spin-coating of both components, GNPs and crosslinker, and enables the deposition of films several tens of nanometers in thickness within a few minutes. X-ray diffraction and conductance measurements reveal the proper adjustment concentration of the crosslinker solution of the critical is in order to prevent the destabilization and coalescence of particles. UV/vis spectroscopy, atomic force microscopy, and conductivity measurements indicate that films prepared via layer-by-layer spin-coating are of comparable quality to coatings prepared via laborious layer-by-layer self-assembly using immersion baths. Because spin-coated films are not bound chemically to the substrate, they can be lifted-off by alkaline underetching and transferred onto 3d-electrodes to produce electrically addressable, freely suspended films. Comparative measurements of the sheet resistances indicate that the transfer process does not compromise the film quality.

  20. Modelling approaches to the dewetting of evaporating thin films of nanoparticle suspensions

    International Nuclear Information System (INIS)

    Thiele, U; Vancea, I; Archer, A J; Robbins, M J; Frastia, L; Stannard, A; Pauliac-Vaujour, E; Martin, C P; Blunt, M O; Moriarty, P J

    2009-01-01

    We review recent experiments on dewetting thin films of evaporating colloidal nanoparticle suspensions (nanofluids) and discuss several theoretical approaches to describe the ongoing processes including coupled transport and phase changes. These approaches range from microscopic discrete stochastic theories to mesoscopic continuous deterministic descriptions. In particular, we describe (i) a microscopic kinetic Monte Carlo model, (ii) a dynamical density functional theory and (iii) a hydrodynamic thin film model. Models (i) and (ii) are employed to discuss the formation of polygonal networks, spinodal and branched structures resulting from the dewetting of an ultrathin 'postcursor film' that remains behind a mesoscopic dewetting front. We highlight, in particular, the presence of a transverse instability in the evaporative dewetting front, which results in highly branched fingering structures. The subtle interplay of decomposition in the film and contact line motion is discussed. Finally, we discuss a simple thin film model (iii) of the hydrodynamics on the mesoscale. We employ coupled evolution equations for the film thickness profile and mean particle concentration. The model is used to discuss the self-pinning and depinning of a contact line related to the 'coffee-stain' effect. In the course of the review we discuss the advantages and limitations of the different theories, as well as possible future developments and extensions.

  1. Photoconductivity studies on amorphous and crystalline TiO{sub 2} films doped with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Valverde-Aguilar, G.; Garcia-Macedo, J.A. [Universidad Nacional Autonoma de Mexico, Departamento de Estado Solido, Instituto de Fisica, Mexico D.F. (Mexico); Renteria-Tapia, V. [Universidad de Guadalajara, Centro Universitario de los Valles, Departamento de Ciencias Naturales y Exactas, Ameca, Jalisco (Mexico); Aguilar-Franco, M. [Universidad Nacional Autonoma de Mexico, Departamento de Fisica Quimica, Instituto de Fisica, Mexico D.F. (Mexico)

    2011-06-15

    In this work, amorphous and crystalline TiO{sub 2} films were synthesized by the sol-gel process at room temperature. The TiO{sub 2} films were doped with gold nanoparticles. The films were spin-coated on glass wafers. The crystalline samples were annealed at 100 C for 30 minutes and sintered at 520 C for 2 h. All films were characterized using X-ray diffraction, transmission electronic microscopy and UV-Vis absorption spectroscopy. Two crystalline phases, anatase and rutile, were formed in the matrix TiO{sub 2} and TiO{sub 2}/Au. An absorption peak was located at 570 nm (amorphous) and 645 nm (anatase). Photoconductivity studies were performed on these films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm. This indicates an ohmic behavior. Crystalline TiO{sub 2}/Au films are more photoconductive than the amorphous ones. (orig.)

  2. Printed silver nanowire antennas with low signal loss at high-frequency radio

    Science.gov (United States)

    Komoda, Natsuki; Nogi, Masaya; Suganuma, Katsuaki; Kohno, Kazuo; Akiyama, Yutaka; Otsuka, Kanji

    2012-05-01

    Silver nanowires are printable and conductive, and are believed to be promising materials in the field of printed electronics. However, the resistivity of silver nanowire printed lines is higher than that of metallic particles or flakes even when sintered at high temperatures of 100-400 °C. Therefore, their applications have been limited to the replacement of transparent electrodes made from high-resistivity materials, such as doped metallic oxides, conductive polymers, carbon nanotubes, or graphenes. Here we report that using printed silver nanowire lines, signal losses obtained in the high-frequency radio were lower than those obtained using etched copper foil antennas, because their surfaces were much smoother than those of etched copper foil antennas. This was the case even though the resistivity of silver nanowire lines was 43-71 μΩ cm, which is much higher than that of etched copper foil (2 μΩ cm). When printed silver nanowire antennas were heated at 100 °C, they achieved signal losses that were much lower than those of silver paste antennas comprising microparticles, nanoparticles, and flakes. Furthermore, using a low temperature process, we succeeded in remotely controlling a commercialized radio-controlled car by transmitting a 2.45 GHz signal via a silver nanowire antenna printed on a polyethylene terephthalate film.Silver nanowires are printable and conductive, and are believed to be promising materials in the field of printed electronics. However, the resistivity of silver nanowire printed lines is higher than that of metallic particles or flakes even when sintered at high temperatures of 100-400 °C. Therefore, their applications have been limited to the replacement of transparent electrodes made from high-resistivity materials, such as doped metallic oxides, conductive polymers, carbon nanotubes, or graphenes. Here we report that using printed silver nanowire lines, signal losses obtained in the high-frequency radio were lower than those

  3. Semiconductor nanowires and templates for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Ying, Xiang

    2009-07-15

    This thesis starts by developing a platform for the organized growth of nanowires directly on a planar substrate. For this, a method to fabricate horizontal porous alumina membranes is studied. The second part of the thesis focuses on the study of nanowires. It starts by the understanding of the growth mechanisms of germanium nanowires and follows by the structural and electrical properties at the single nanowire level. Horizontally aligned porous anodic alumina (PAA) was used as a template for the nanowire synthesis. Three PAA arrangements were studied: - high density membranes - micron-sized fingers - multi-contacts Membranes formed by a high density of nanopores were obtained by anodizing aluminum thin films. Metallic and semiconducting nanowires were synthesized into the PAA structures via DC deposition, pulsed electro-depostion and CVD growth. The presence of gold, copper, indium, nickel, tellurium, and silicon nanowires inside PAA templates was verified by SEM and EDX analysis. Further, room-temperature transport measurements showed that the pores are completely filled till the bottom of the pores. In this dissertation, single crystalline and core-shell germanium nanowires are synthesized using indium and bismuth as catalyst in a chemical vapor deposition procedure with germane (GeH{sub 4}) as growth precursor. A systematic growth study has been performed to obtain high aspect-ratio germanium nanowires. The influence of the growth conditions on the final morphology and the crystalline structure has been determined via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). In the case of indium catalyzed germanium nanowires, two different structures were identified: single crystalline and crystalline core-amorphous shell. The preferential growth axis of both kinds of nanowires is along the [110] direction. The occurrence of the two morphologies was found to only depend on the nanowire dimension. In the case of bismuth

  4. Time-resolved analysis of the white photoluminescence from chemically synthesized SiC{sub x}O{sub y} thin films and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Tabassum, Natasha; Nikas, Vasileios; Ford, Brian; Huang, Mengbing; Kaloyeros, Alain E.; Gallis, Spyros, E-mail: sgalis@sunypoly.edu [Colleges of Nanoscale Sciences and Engineering, SUNY Polytechnic Institute, Albany, New York 12203 (United States)

    2016-07-25

    The study reported herein presents results on the room-temperature photoluminescence (PL) dynamics of chemically synthesized SiC{sub x}O{sub y≤1.6} (0.19 < x < 0.6) thin films and corresponding nanowire (NW) arrays. The PL decay transients of the SiC{sub x}O{sub y} films/NWs are characterized by fast luminescence decay lifetimes that span in the range of 350–950 ps, as determined from their deconvoluted PL decay spectra and their stretched-exponential recombination behavior. Complementary steady-state PL emission peak position studies for SiC{sub x}O{sub y} thin films with varying C content showed similar characteristics pertaining to the variation of their emission peak position with respect to the excitation photon energy. A nearly monotonic increase in the PL energy emission peak, before reaching an energy plateau, was observed with increasing excitation energy. This behavior suggests that band-tail states, related to C-Si/Si-O-C bonding, play a prominent role in the recombination of photo-generated carriers in SiC{sub x}O{sub y}. Furthermore, the PL lifetime behavior of the SiC{sub x}O{sub y} thin films and their NWs was analyzed with respect to their luminescence emission energy. An emission-energy-dependent lifetime was observed, as a result of the modulation of their band-tail states statistics with varying C content and with the reduced dimensionality of the NWs.

  5. Carbon nanostructured films modified by metal nanoparticles supported on filtering membranes for electroanalysis.

    Science.gov (United States)

    Paramo, Erica; Palmero, Susana; Heras, Aranzazu; Colina, Alvaro

    2018-02-01

    A novel methodology to prepare sensors based on carbon nanostructures electrodes modified by metal nanoparticles is proposed. As a proof of concept, a novel bismuth nanoparticle/carbon nanofiber (Bi-NPs/CNF) electrode and a carbon nanotube (CNT)/gold nanoparticle (Au-NPs) have been developed. Bi-NPs/CNF films were prepared by 1) filtering a dispersion of CNFs on a polytetrafluorethylene (PTFE) filter, and 2) filtering a dispersion of Bi-NPs chemically synthesized through this CNF/PTFE film. Next the electrode is prepared by sticking the Bi-NPs/CNF/PTFE film on a PET substrate. In this work, Bi-NPs/CNF ratio was optimized using a Cd 2+ solution as a probe sample. The Cd anodic stripping peak intensity, registered by differential pulse anodic stripping voltammetry (DPASV), is selected as target signal. The voltammograms registered for Cd stripping with this Bi-NPs/CNF/PTFE electrode showed well-defined and highly reproducible electrochemical. The optimized Bi-NPs/CNF electrode exhibits a Cd 2+ detection limit of 53.57 ppb. To demonstrate the utility and versatility of this methodology, single walled carbon nanotubes (SWCNTs) and gold nanoparticles (Au-NPs) were selected to prepare a completely different electrode. Thus, the new Au-NPs/SWCNT/PTFE electrode was tested with a multiresponse technique. In this case, UV/Vis absorption spectroelectrochemistry experiments were carried out for studying dopamine, demonstrating the good performance of the Au-NPs/SWCNT electrode developed. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Optical Detection and Sizing of Single Nano-Particles Using Continuous Wetting Films

    Science.gov (United States)

    Hennequin, Yves; McLeod, Euan; Mudanyali, Onur; Migliozzi, Daniel; Ozcan, Aydogan; Dinten, Jean-Marc

    2013-01-01

    The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm2 using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm2. These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs. PMID:23889001

  7. The processing of polyelectrolyte-covered magnetite nanoparticles in the form of nanostructured thin films

    International Nuclear Information System (INIS)

    Marangoni, Valéria S.; Martins, Marccus Victor A.; Souza, José A.; Oliveira, Osvaldo N.; Zucolotto, Valtencir; Crespilho, Frank N.

    2012-01-01

    Magnetic nanoparticles are promising for a variety of applications, such as biomedical devices, spin electronics, magnetic data storage media, to name a few. However, these goals may only be reached if stable and organized structures are fabricated. In this article, we report on a single-step synthetic route with the coprecipitation method, in which iron oxide magnetic nanoparticles (Fe 3 O 4 NPs) were stabilized in aqueous media using the poly(diallyldimethylammonium chloride) (PDAC) polyelectrolyte. The Fe 3 O 4 NPs had a diameter of ca. 5 nm, according to transmission electron microscopy (TEM) images, being arranged in an inverse spinel structure typical of magnetite. An investigation with infrared spectroscopy indicated that the mechanisms of stabilization in the polymer matrix were based on the interaction between quaternary amide groups from PDAC and the nanoparticle surface. The Fe 3 O 4 -PDAC NPs exhibited considerable magnetic susceptibility, with a monotonic increase in the magnetization with decreasing temperature. These Fe 3 O 4 -PDAC NPs were immobilized in layer-by-layer (LbL) films, being alternated with layers of poly(vinylsulfonic acid) (PVS). The LbL films were much rougher than typical films made with polyelectrolytes, and Fe 3 O 4 -PDAC NPs have been responsible for the high electrocatalytic activity toward H 2 O 2 reduction, with an overpotential shift of 0.69 V. Overall, the stability, magnetic properties and film-forming ability indicate that the Fe 3 O 4 -PDAC NPs may be used for nanoelectronics and bioelectrochemical devices requiring reversible and magnetic redox materials.

  8. Controlled fabrication of the strong emission YVO{sub 4}:Eu{sup 3+} nanoparticles and nanowires by microwave assisted chemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Huong, Tran Thu, E-mail: tthuongims@gmail.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Vinh, Le Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Mining and Geology (Viet Nam); Phuong, Ha Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Medicine (Viet Nam); Khuyen, Hoang Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Anh, Tran Kim [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam); Tu, Vu Duc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Physics, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 62102, Taiwan (China); Minh, Le Quoc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam)

    2016-05-15

    In this report, we are presenting the controlled fabrication results of the strong emission YVO{sub 4}: Eu{sup 3+} nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO{sub 4}: Eu{sup 3+} prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO{sub 4}: Eu{sup 3+} nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of {sup 5}D{sub 0}–{sup 7}F{sub j} (j=1, 2, 3, and 4) of Eu{sup 3+} ions with the highest luminescence intensity of {sup 5}D{sub 0}→{sup 7}F{sub 2} transition. - Highlights: • The strong emission YVO{sub 4}:Eu{sup 3+} nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO{sub 4}:Eu{sup 3+} nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO{sub 4}:Eu{sup 3+} nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  9. Synthesis and visible-light-induced catalytic activity of Ag{sub 2}S-coupled TiO{sub 2} nanoparticles and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Xie Yi; Heo, Sung Hwan; Kim, Yong Nam; Yoo, Seung Hwa; Cho, Sung Oh, E-mail: socho@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong, Yuseong, Daejeon 305-701 (Korea, Republic of)

    2010-01-08

    We present the synthesis and visible-light-induced catalytic activity of Ag{sub 2}S-coupled TiO{sub 2} nanoparticles (NPs) and TiO{sub 2} nanowires (NWs). Through a simple wet chemical process from a mixture of peroxo titanic acid (PTA) solution, thiourea and AgAc, a composite of Ag{sub 2}S NPs and TiO{sub 2} NPs with sizes of less than 7 nm was formed. When the NP composite was further treated with NaOH solution followed by annealing at ambient conditions, a new nanocomposite material comprising Ag{sub 2}S NPs on TiO{sub 2} NWs was created. Due to the coupling with such a low bandgap material as Ag{sub 2}S, the TiO{sub 2} nanocomposites could have a visible-light absorption capability much higher than that of pure TiO{sub 2}. As a result, the synthesized Ag{sub 2}S/TiO{sub 2} nanocomposites exhibited much higher catalytic efficiency for the decomposition of methyl orange than commercial TiO{sub 2} (Degussa P25, Germany) under visible light.

  10. Green synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, D.A. [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Hui, K.S., E-mail: kshui@hanyang.ac.kr [Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Hui, K.N., E-mail: bizhui@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Cho, Y.R. [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Zhou, Wei [Department of Mechanical and Electrical Engineering, Xiamen University, Xiamen 361005 (China); Hong, Xiaoting [School of Chemistry and Environment, South China Normal University, Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, Guangzhou 510006 (China); Chun, Ho-Hwan [Global Core Research Center for Ships and Offshore Plants (GCRC-SOP), Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2014-04-01

    Graphical abstract: - Highlights: • A green facile chemical approach to control the dimensions of Ag nanoparticles–graphene oxide (AgNPs/GO) composites was performed at room temperature. • With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. • The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N{sub 2}/H{sub 2} gas flow for 1 h. • The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). - Abstract: A green facile chemical approach to control the dimensions of Ag nanoparticles–graphene oxide (AgNPs/GO) composites was performed by the in situ ultrasonication of a mixture of AgNO{sub 3} and graphene oxide solutions with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N{sub 2}/H{sub 2} gas flow for 1 h. Four-point probe measurements showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). The formation mechanisms of the as-prepared AgNPs/rGO films are proposed. This study provides a guide to controlling the dimensions of AgNPs/rGO films, which might hold promise as advanced materials for a range of analytical applications, such as catalysis, sensors and microchips.

  11. Green synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films

    International Nuclear Information System (INIS)

    Dinh, D.A.; Hui, K.S.; Hui, K.N.; Cho, Y.R.; Zhou, Wei; Hong, Xiaoting; Chun, Ho-Hwan

    2014-01-01

    Graphical abstract: - Highlights: • A green facile chemical approach to control the dimensions of Ag nanoparticles–graphene oxide (AgNPs/GO) composites was performed at room temperature. • With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. • The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N 2 /H 2 gas flow for 1 h. • The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). - Abstract: A green facile chemical approach to control the dimensions of Ag nanoparticles–graphene oxide (AgNPs/GO) composites was performed by the in situ ultrasonication of a mixture of AgNO 3 and graphene oxide solutions with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N 2 /H 2 gas flow for 1 h. Four-point probe measurements showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). The formation mechanisms of the as-prepared AgNPs/rGO films are proposed. This study provides a guide to controlling the dimensions of AgNPs/rGO films, which might hold promise as advanced materials for a range of analytical applications, such as catalysis, sensors and microchips

  12. Nanoparticle and nanorod films deposited by matrix assisted pulsed laser evaporation

    Science.gov (United States)

    Caricato, A. P.; Cesaria, M.; Luches, A.; Martino, M.

    2012-07-01

    The promising results obtained with the MAPLE-deposition of nanostructured thin films, to be used in different fields, are reviewed. Nanoparticles (TiO2, SnO2, CdS) and nanorods (TiO2) with well defined dimensions were suspended in appropriate solvents (distilled water, toluene) with low concentration (1wt% or less). The solutions were flash frozen at the liquid nitrogen temperature to form the targets to be laser irradiated. The MAPLE process allowed a successful transfer from the target to rough and flat substrates, preserving the starting composition and crystalline phase of the nanostructures in a wide range of experimental conditions. In contrast, a careful choice of the laser fluence is mandatory to avoid shape modifications. Growth of metal nanoparticles with a low dispersion in size was also obtained by the MAPLE technique, starting from target solutions of a metallorganic element (AcPd) diluted in different solvents (acetone, diethyl ether). It seems that selecting the solvent with appropriate values of viscosity and boiling temperatures, it is possible to modulate the nanoparticles size. Most of the deposited nanostructured films were tested as sensing elements for gas sensors.

  13. Flow and heat transfer in water based liquid film fluids dispensed with graphene nanoparticles

    Directory of Open Access Journals (Sweden)

    Samina Zuhra

    2018-03-01

    Full Text Available The unsteady flow and heat transfer characteristics of electrically conducting water based thin liquid film non-Newtonian (Casson and Williamson nanofluids dispensed with graphene nanoparticles past a stretching sheet are considered in the presence of transverse magnetic field and non-uniform heat source/sink. Embedding the graphene nanoparticles effectively amplifies the thermal conductivity of Casson and Williamson nanofluids. Ordinary differential equations together with the boundary conditions are obtained through similarity variables from the governing equations of the problem, which are solved by the HAM (Homotopy Analysis Method. The solution is expressed through graphs and illustrated which show the influences of all the parameters. The convergence of the HAM solution for the linear operators is obtained. Favorable comparison with previously published research paper is performed to show the correlation for the present work. Skin friction coefficient and Nusselt number are presented through Tables and graphs which show the validation for the achieved results demonstrating that the thin liquid films results from this study are in close agreement with the results reported in the literature. Results achieved by HAM and residual errors are evaluated numerically, given in Tables and also depicted graphically which show the accuracy of the present work. Keywords: Graphene nanoparticles, MHD, Casson and Williamson nanofluids, Stretching sheet, Skin friction coefficient, Nusselt number, Residual errors, Homotopy Analysis Method

  14. Magnetic Composite Thin Films of Fe{sub x}O{sub y} Nanoparticles and Photocrosslinked Dextran Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Brunsen, Annette, E-mail: brunsen@mpip-mainz.mpg.de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Department of Chemistry, Technical University Darmstadt, Petersenstr. 22, 64287 Darmstadt (Germany); Utech, Stefanie, E-mail: utech@uni-mainz.de [Johannes Gutenberg University Mainz, Institute of Physical Chemistry, Jakob-Welder-Weg 11, 55099 Mainz (Germany); Institut fuer Mikrotechnik Mainz GmbH (IMM), Carl-Zeiss-Str. 18-20, 55129 Mainz, German (Germany); Maskos, Michael, E-mail: maskos@uni-mainz.de [Institut fuer Mikrotechnik Mainz GmbH (IMM), Carl-Zeiss-Str. 18-20, 55129 Mainz, German (Germany); Knoll, Wolfgang, E-mail: Wolfgang.Knoll@ait.ac.at [Austrian Institute of Technology, Tech Gate Vienna, Donau-City-Str. 1, 1220 Wien (Austria); Jonas, Ulrich, E-mail: jonas@mpip-mainz.mpg.de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany) and Macromolecular Chemistry, Department Chemistry - Biology, University of Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen (Germany) and Foundation for Research and Technology - Hellas - FORTH, Institute of Electronic Structure and Laser (IESL), Bio-Organic Materials Chemistry Laboratory - BOMCLab, Nikolaou Plastira 100, Vassilika Vouton, 71110 Heraklion, Crete (Greece)

    2012-04-15

    Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP-HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By utilizing a surface layer of a photoreactive adhesion promoter on the substrates, the MNP-HG films were covalently immobilized during photocrosslinking. The high stability of the composite was documented by rinsing experiments with UV-Vis spectroscopy, while surface plasmon resonance and optical waveguide mode spectroscopy was employed to investigate the swelling behavior in dependence of the nanoparticle concentration, the particle type, and salt concentration. - Highlights: Black-Right-Pointing-Pointer blending of iron oxide nanoparticles with photocrosslinkable carboxymethyldextran. Black-Right-Pointing-Pointer UV irradiation of blend yields surface-attached, magnetic hydrogel films. Black-Right-Pointing-Pointer film characterization by surface plasmon resonance/optical waveguide spectroscopy. Black-Right-Pointing-Pointer swelling decreases with increasing nanoparticle content. Black-Right-Pointing-Pointer swelling decreases with increasing NaCl salt concentration in the aqueous medium.

  15. Atmospheric pulsed laser deposition of plasmonic nanoparticle films of silver with flowing gas and flowing atmospheric plasma

    Science.gov (United States)

    Khan, T. M.; Pokle, A.; Lunney, J. G.

    2018-04-01

    Two methods of atmospheric pulsed laser deposition of plasmonic nanoparticle films of silver are described. In both methods the ablation plume, produced by a 248 nm, 20 ns excimer laser in gas, is strongly confined near the target and forms a nanoparticle aerosol. For both the flowing gas, and the atmospheric plasma from a dielectric barrier discharge plasma source, the aerosol is entrained in the flow and carried to a substrate for deposition. The nanoparticle films produced by both methods were examined by electron microscopy and optical absorption spectroscopy. With plasma assistance, the deposition rate was significantly enhanced and the film morphology altered. With argon gas, isolated nanoparticles of 20 nm size were obtained, whereas in argon plasma, the nanoparticles are aggregated in clusters of 90 nm size. Helium gas also leads to the deposition of isolated nanoparticles, but with helium plasma, two populations of nanoparticles are observed: one of rounded particles with a mean size of 26 nm and the other of faceted particles with a mean size 165 nm.

  16. Characterization of dip-coated ITO films derived from nanoparticles synthesized by low-pressure spray pyrolysis

    International Nuclear Information System (INIS)

    Ogi, Takashi; Iskandar, Ferry; Itoh, Yoshifumi; Okuyama, Kikuo

    2006-01-01

    In 2 O 3 :Sn (Indium Tin Oxide; ITO) films were prepared from a sol solution with highly crystalline ITO nanoparticles (less than 20 nm in size with 10 at.% Sn) which had been prepared by low-pressure spray pyrolysis (LPSP) in a single step. The ITO sol solution was prepared by dispersing LPSP-prepared ITO nanoparticles into ultra pure water. The nanoparticle ITO film was deposited on a glass substrate using a dip-coating method and then annealed in air at various temperatures. The optical transmittances of the ITO films were measured by UV-Vis spectrometry, and the films were found to have a high transparency to visible light (in the case of a film thickness of 250 nm annealed at 400 deg. C, the transparency was in excess of 95% over the range λ=450-800 nm, with a maximum value near 100% at wavelengths above λ=700 nm). The optical transmittances of the films were influenced by the size of the ITO particle used, the film thickness and the annealing temperature. The ITO films showed a minimum resistivity of 9.5x10 -2 Ω cm, and their resistivity was affected by both the ITO particle size and the annealing temperature used

  17. Optimization, Yield Studies and Morphology of WO3Nano-Wires Synthesized by Laser Pyrolysis in C2H2and O2Ambients—Validation of a New Growth Mechanism

    Directory of Open Access Journals (Sweden)

    Sideras-Haddad E

    2008-01-01

    Full Text Available Abstract Laser pyrolysis has been used to synthesize WO3nanostructures. Spherical nano-particles were obtained when acetylene was used to carry the precursor droplet, whereas thin films were obtained at high flow-rates of oxygen carrier gas. In both environments WO3nano-wires appear only after thermal annealing of the as-deposited powders and films. Samples produced under oxygen carrier gas in the laser pyrolysis system gave a higher yield of WO3nano-wires after annealing than the samples which were run under acetylene carrier gas. Alongside the targeted nano-wires, the acetylene-ran samples showed trace amounts of multi-walled carbon nano-tubes; such carbon nano-tubes are not seen in the oxygen-processed WO3nano-wires. The solid–vapour–solid (SVS mechanism [B. Mwakikunga et al., J. Nanosci. Nanotechnol., 2008] was found to be the possible mechanism that explains the manner of growth of the nano-wires. This model, based on the theory from basic statistical mechanics has herein been validated by length-diameter data for the produced WO3nano-wires.

  18. Photoluminescent characteristics of ion beam synthesized Ge nanoparticles in thermally grown SiO2 films

    International Nuclear Information System (INIS)

    Yu, C.F.; Chao, D.S.; Chen, Y.-F.; Liang, J.H.

    2013-01-01

    Prospects of developing into numerous silicon-based optoelectronic applications have prompted many studies on the optical properties of Ge nanoparticles within a silicon oxide (SiO 2 ) matrix. Even with such abundant studies, the fundamental mechanism underlying the Ge nanoparticle-induced photoluminescence (PL) is still an open question. In order to elucidate the mechanism, we dedicate this study to investigating the correlation between the PL properties and microstructure of the Ge nanoparticles synthesized in thermally grown SiO 2 films. Our spectral data show that the peak position, at ∼3.1 eV or 400 nm, of the PL band arising from the Ge nanoparticles was essentially unchanged under different Ge implantation fluences and the temperatures of the following annealing process, whereas the sample preparation parameters modified or even fluctuated (in the case of the annealing temperature) the peak intensity considerably. Given the microscopically observed correlation between the nanoparticle structure and the sample preparation parameters, this phenomenon is consistent with the mechanism in which the oxygen-deficiency-related defects in the Ge/SiO 2 interface act as the major luminescence centers; this mechanism also successfully explains the peak intensity fluctuation with the annealing temperature. Moreover, our FTIR data indicate the formation of GeO x upon ion implantation. Since decreasing of the oxygen-related defects by the GeO x formation is expected to be correlated with the annealing temperature, presence of the GeO x renders further experimental support to the oxygen defect mechanism. This understanding may assist the designing of the manufacturing process to optimize the Ge nanoparticle-based PL materials for different technological applications

  19. Directed self-assembly of nanoporous metallic- and bimetallic nanoparticle thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pietsch, Torsten [Fachbereich Physik, Universitaet Konstanz (Germany); Gindy, Nabil; Fahmi, Amir [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham (United Kingdom)

    2010-07-01

    Nanoporous thin films attracted considerable interest due to potential applications in optical coatings, catalysis, sensors as well as electronic devices. Recently, such films were prepared by post deposition treatments. The present study is focused on the fabrication of nanoporous thin films via directed self-assembly of hybrid materials. Due to the nature of this process no additional treatments are necessary to develop the pores. Hierarchical nanoporous structures are fabricated directly via deposition of polymer templated Au-nanoparticles onto hydrophilic substrates. These films exhibit two different pore diameters and a total pore density of more than 10{sup 10} holes per cm{sup 2}. Control over the pore size is achieved by changing the molecular weight of the PS-b-P4VP diblock copolymer. Moreover, the porous morphology is used as a template to fabricate bimetallic nanostructured thin films. Such well-defined nanostructures, not only exhibit unique physical properties but also provide control over the hydrophobicity of the coated surfaces.

  20. Motion of Adsorbed Nano-Particles on Azobenzene Containing Polymer Films

    Directory of Open Access Journals (Sweden)

    Sarah Loebner

    2016-12-01

    Full Text Available We demonstrate in situ recorded motion of nano-objects adsorbed on a photosensitive polymer film. The motion is induced by a mass transport of the underlying photoresponsive polymer material occurring during irradiation with interference pattern. The polymer film contains azobenzene molecules that undergo reversible photoisomerization reaction from trans- to cis-conformation. Through a multi-scale chain of physico-chemical processes, this finally results in the macro-deformations of the film due to the changing elastic properties of polymer. The topographical deformation of the polymer surface is sensitive to a local distribution of the electrical field vector that allows for the generation of dynamic changes in the surface topography during irradiation with different light interference patterns. Polymer film deformation together with the motion of the adsorbed nano-particles are recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the surface deformation. The particles undergo either translational or rotational motion. The direction of particle motion is towards the topography minima and opposite to the mass transport within the polymer film. The ability to relocate particles by photo-induced dynamic topography fluctuation offers a way for a non-contact simultaneous manipulation of a large number of adsorbed particles just in air at ambient conditions.

  1. Fabrication of TiO2/PU Superhydrophobic Film by Nanoparticle Assisted Cast Micromolding Process.

    Science.gov (United States)

    Li, Jie; Zheng, Jianyong; Zhang, Jing; Feng, Jie

    2016-06-01

    Lotus-like surfaces have attracted great attentions in recent years for their wide applications in water repellency, anti-fog and self-cleaning. This paper introduced a novel process, nanoparticle assisted cast micromolding, to create polymer film with superhydrophobic surface. Briefly, waterborne polyurethane (WPU) sol and nano TiO2/WPU sol were each cast onto the featured surfaces of the poly(dimethylsiloxane) (PDMS) stamps replicated from fresh lotus leaves. After being dried and peeled off from the stamps, PU and TiO2/WPU replica films were created respectively. To the former, only high hydrophobic property was observed with static water contact angle (WCA) at 142.5 degrees. While to the later, superhydrophobic property was obtained with WCA more than 150 degrees and slide angle less than 3 degrees. Scanning electron microscopy (SEM) imaging showed that the PU replica film only had the micro-papillas and the TiO2/PU replica film not only had micro papillas but also had a large number of nano structures distributed on and between the micro-papillas. Such nano and micro hierarchical structures were very similar with those on the natural lotus leaf surface, thus was the main reason for causing superhydrophobic property. Although an elastic PDMS stamp from lotus leaf was used in herein process, hard molds may also be used in theory. This study supplied an alternative technique for large scale production of polymeric films with superhydrophobic.

  2. Co nanoparticles induced resistive switching and magnetism for the electrochemically deposited polypyrrole composite films.

    Science.gov (United States)

    Xu, Zedong; Gao, Min; Yu, Lina; Lu, Liying; Xu, Xiaoguang; Jiang, Yong

    2014-10-22

    The resistive switching behavior of Co-nanoparticle-dispersed polypyrrole (PPy) composite films is studied. A novel design method for resistive random access memory (ReRAM) is proposed. The conducting polymer films with metal nanocrystal (NC)-dispersed carbon chains induce the spontaneous oxidization of the conducting polymer at the surface. The resistive switching behavior is achieved by an electric field controlling the oxygen ion mobility between the metal electrode and the conducting polymer film to realize the mutual transition between intrinsic conduction (low resistive state) and oxidized layer conduction (high resistive state). Furthermore, the formation process of intrinsic conductive paths can be effectively controlled in the conducting polymer ReRAM using metal NCs in films because the inner metal NCs induce electric field lines converging around them and the intensity of the electric field at the tip of NCs can greatly exceed that of the other region. Metal NCs can also bring new characteristics for ReRAM, such as magnetism by dispersing magnetic metal NCs in polymer, to obtain multifunctional electronic devices or meet some special purpose in future applications. Our works will enrich the application fields of the electromagnetic PPy composite films and present a novel material for ReRAM devices.

  3. Electromechanical study of polyurethane films with carbon black nanoparticles for MEMS actuators

    International Nuclear Information System (INIS)

    Roussel, M; Deman, A-L; Chateaux, J-F; Malhaire, C; Petit, L; Seveyrat, L; Galineau, J; Guiffard, B; Seguineau, C; Desmarres, J-M; Martegoutte, J

    2014-01-01

    Pure polyurethane and nanocomposite carbon black (CB) polyurethane solutions were deposited by spin-coating on a silicon substrate using gold as the adhesion layer and electrode. Different test structures were achieved for electrical and mechanical characterizations. The incorporation of CB nanoparticles in the polyurethane matrix has a significant influence on the dielectric permittivity of the material with an increase of about one third of its value. The Young's modulus of PU and nanocomposite PU films was determined by different characterization methods. Nanoindentation experiments have pointed out a Young's modulus gradient through the film thickness. By performing mechanical tests (tensile, bulge, point deflection) on freestanding films, an average Young's modulus value of about 30 MPa was found as well as a residual stress value of about 0.4 MPa. However, no influence of the presence of the nanoparticles was found. Finally, several MEMS actuators were realized and characterized. At their fundamental resonance frequency, the actuation of the nanocomposite membranes is more efficient than that of pure polyurethane. However, the time constant of the material seems to provide a major barrier for the development of high-frequency PU-based micro-actuators. (paper)

  4. Antibacterial property of Ag nanoparticle-impregnated N-doped titania films under visible light

    Science.gov (United States)

    Wong, Ming-Show; Chen, Chun-Wei; Hsieh, Chia-Chun; Hung, Shih-Che; Sun, Der-Shan; Chang, Hsin-Hou

    2015-07-01

    Photocatalysts produce free radicals upon receiving light energy; thus, they possess antibacterial properties. Silver (Ag) is an antibacterial material that disrupts bacterial physiology. Our previous study reported that the high antibacterial property of silver nanoparticles on the surfaces of visible light-responsive nitrogen-doped TiO2 photocatalysts [TiO2(N)] could be further enhanced by visible light illumination. However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use. To overcome this limitation, we developed TiO2(N)/Ag/TiO2(N) sandwich films in which the silver is embedded between two TiO2(N) layers. Various characteristics, including silver and nitrogen amounts, were examined in the composite materials. Various analyses, including electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and ultraviolet-visible absorption spectrum and methylene blue degradation rate analyses, were performed. The antibacterial properties of the composite materials were investigated. Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated. This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

  5. Highly Conductive, Transparent Flexible Films Based on Metal Nanoparticle-Carbon Nanotube Composites

    Directory of Open Access Journals (Sweden)

    Wen-Yin Ko

    2013-01-01

    Full Text Available Metallic nanoparticles decorated on MWCNTs based transparent conducting thin films (TCFs show a cheap and efficient option for the applications in touch screens and the replacement of the ITO film because of their interesting properties of electrical conductivity, mechanical property, chemical inertness, and other unique properties, which may not be accessible by their individual components. However, a great challenge that always remains is to develop effective ways to prepare junctions between metallic nanoparticles and MWCNTs for the improvement of high-energy barriers, high contact resistances, and weak interactions which could lead to the formation of poor conducting pathways and result in the CNT-based devices with low mechanical flexibility. Herein, we not only discuss recent progress in the preparation of MNP-CNT flexible TCFs but also describe our research studies in the relevant areas. Our result demonstrated that the MNP-CNT flexible TCFs we prepared could achieve a highly electrical conductivity with the sheet resistance of ~100 ohm/sq with ~80% transmittance at 550 nm even after being bent 500 times. This electrical conductivity is much superior to the performances of other MWCNT-based transparent flexible films, making it favorable for next-generation flexible touch screens and optoelectronic devices.

  6. Highly Hydrophilic Thin-Film Composite Forward Osmosis Membranes Functionalized with Surface-Tailored Nanoparticles

    KAUST Repository

    Tiraferri, Alberto

    2012-09-26

    Thin-film composite polyamide membranes are state-of-the-art materials for membrane-based water purification and desalination processes, which require both high rejection of contaminants and high water permeabilities. However, these membranes are prone to fouling when processing natural waters and wastewaters, because of the inherent surface physicochemical properties of polyamides. The present work demonstrates the fabrication of forward osmosis polyamide membranes with optimized surface properties via facile and scalable functionalization with fine-tuned nanoparticles. Silica nanoparticles are coated with superhydrophilic ligands possessing functional groups that impart stability to the nanoparticles and bind irreversibly to the native carboxyl moieties on the membrane selective layer. The tightly tethered layer of nanoparticles tailors the surface chemistry of the novel composite membrane without altering the morphology or water/solute permeabilities of the membrane selective layer. Surface characterization and interfacial energy analysis confirm that highly hydrophilic and wettable membrane surfaces are successfully attained. Lower intermolecular adhesion forces are measured between the new membrane materials and model organic foulants, indicating the presence of a bound hydration layer at the polyamide membrane surface that creates a barrier for foulant adhesion. © 2012 American Chemical Society.

  7. Hot-Electron Intraband Luminescence from Single Hot Spots in Noble-Metal Nanoparticle Films

    Science.gov (United States)

    Haug, Tobias; Klemm, Philippe; Bange, Sebastian; Lupton, John M.

    2015-08-01

    Disordered noble-metal nanoparticle films exhibit highly localized and stable nonlinear light emission from subdiffraction regions upon illumination by near-infrared femtosecond pulses. Such hot spot emission spans a continuum in the visible and near-infrared spectral range. Strong plasmonic enhancement of light-matter interaction and the resulting complexity of experimental observations have prevented the development of a universal understanding of the origin of light emission. Here, we study the dependence of emission spectra on excitation irradiance and provide the most direct evidence yet that the continuum emission observed from both silver and gold nanoparticle aggregate surfaces is caused by recombination of hot electrons within the conduction band. The electron gas in the emitting particles, which is effectively decoupled from the lattice temperature for the duration of emission, reaches temperatures of several thousand Kelvin and acts as a subdiffraction incandescent light source on subpicosecond time scales.

  8. Surface modification of polyamide thin film composite membrane by coating of titanium dioxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Thu Hong Anh Ngo

    2016-12-01

    Full Text Available In this paper, the coating of TiO2 nanoparticles onto the surface of a polyamide thin film composite nanofiltration membrane has been studied. Changes in the properties and separation performance of the modified membranes were systematically characterized. The experimental results indicated that the membrane surface hydrophilicity was significantly improved by the presence of the coated TiO2 nanoparticles with subsequent UV irradiation. The separation performance of the UV-irradiated TiO2-coated membranes was improved with a great enhancement of flux and a very high retention for removal of residual dye in an aqueous feed solution. The antifouling property of the UV-irradiated TiO2-coated membranes was enhanced with higher maintained flux ratios and lower irreversible fouling factors compared with an uncoated membrane.

  9. Thin porous indium tin oxide nanoparticle films: effects of annealing in vacuum and air

    International Nuclear Information System (INIS)

    Ederth, J.; Hultaaker, A.; Niklasson, G.A.; Granqvist, C.G.; Heszler, P.; Doorn, A.R. van; Jongerius, M.J.; Burgard, D.

    2005-01-01

    Electrical and optical properties were investigated in porous thin films consisting of In 2 O 3 :Sn (indium tin oxide; ITO) nanoparticles. The temperature-dependent resistivity was successfully described by a fluctuation-induced tunneling model, indicating a sample morphology dominated by clusters of ITO nanoparticles separated by insulating barriers. An effective-medium model, including the effect of ionized impurity scattering, was successfully fitted to measured reflectance and transmittance. Post-deposition treatments were carried out at 773 K for 2 h in both air and vacuum. It is shown that vacuum annealing increases either the barrier width or the area between two conducting clusters in the samples and, furthermore, an extra optical absorption occurs close to the band gap. A subsequent air annealing then reduces the effect of the barriers on the electrical properties and diminishes the absorption close to the band gap. (orig.)

  10. Controlled fabrication of gold nanoparticles biomediated by glucose oxidase immobilized on chitosan layer-by-layer films

    International Nuclear Information System (INIS)

    Caseli, Luciano; Santos, David S. dos; Aroca, Ricardo F.; Oliveira, Osvaldo N.

    2009-01-01

    The control of size and shape of metallic nanoparticles is a fundamental goal in nanochemistry, and crucial for applications exploiting nanoscale properties of materials. We present here an approach to the synthesis of gold nanoparticles mediated by glucose oxidase (GOD) immobilized on solid substrates using the Layer-by-Layer (LbL) technique. The LbL films contained four alternated layers of chitosan and poly(styrene sulfonate) (PSS), with GOD in the uppermost bilayer adsorbed on a fifth chitosan layer: (chitosan/PSS) 4 /(chitosan/GOD). The films were inserted into a solution containing gold salt and glucose, at various pHs. Optimum conditions were achieved at pH 9, producing gold nanoparticles of ca. 30 nm according to transmission electron microscopy. A comparative study with the enzyme in solution demonstrated that the synthesis of gold nanoparticles is more efficient using immobilized GOD.

  11. Preparation of ordered silver angular nanoparticles array in block copolymer film for surface-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Svanda, J. [University of Chemistry and Technology, Department of Solid State Engineering (Czech Republic); Gromov, M. V. [University of Minnesota Duluth, Department of Chemistry and Biochemistry (United States); Kalachyova, Y. [University of Chemistry and Technology, Department of Solid State Engineering (Czech Republic); Postnikov, P. S. [Tomsk Polytechnic University, Department of Technology of Organic Substances and Polymer Materials (Russian Federation); Svorcik, V.; Lyutakov, O., E-mail: lyutakoo@vscht.cz [University of Chemistry and Technology, Department of Solid State Engineering (Czech Republic)

    2016-10-15

    We report a single-step method of preparation of ordered silver nanoparticles array through template-assisted nanoparticles synthesis in the semidried block copolymer film. Ordered nanoparticles were prepared on different substrates by the proper choice of solvents combination and preparation procedure. In particular, block copolymer and silver nitrate were dissolved in the mix of tetrahydrofuran, toluene, and n-methylpyrolidone. During short spin-coating procedure ordering of block copolymer, evaporation of toluene and preferential silver redistribution into poly(4-vinylpyridine) block occurred. Rapid heating of semidry film initiated silver reduction, removing of residual solvent and creation of ordered silver array. After polymer removing silver nanoparticles array was tested as a suitable candidate for subdiffraction plasmonic application–surface-enhanced Raman scattering. Enhancement factor was calculated and compared with the literature data.

  12. Optical and AFM study of electrostatically assembled films of CdS and ZnS colloid nanoparticles

    International Nuclear Information System (INIS)

    Suryajaya; Nabok, A.; Davis, F.; Hassan, A.; Higson, S.P.J.; Evans-Freeman, J.

    2008-01-01

    CdS and ZnS semiconducting colloid nanoparticles coated with the organic shell, containing either SO 3 - or NH 2 + groups, were prepared using the aqueous phase synthesis. The multilayer films of CdS (or ZnS) were deposited onto glass, quartz and silicon substrates using the technique of electrostatic self-assembly. The films produced were characterized with UV-vis spectroscopy, spectroscopic ellipsometry and atomic force microscopy. A substantial blue shift of the main absorption band with respect to the bulk materials was found for both CdS and ZnS films. The Efros equation in the effective mass approximation (EMA) theoretical model allowed the evaluation of the nanoparticle radius of 1.8 nm, which corresponds well to the ellipsometry results. AFM shows the formation of larger aggregates of nanoparticles on solid surfaces

  13. Chemically controlled interfacial nanoparticle assembly into nanoporous gold films for electrochemical applications

    DEFF Research Database (Denmark)

    Christiansen, Mikkel U. -B.; Seselj, Nedjeljko; Engelbrekt, Christian

    2018-01-01

    at the liquid/air interface starting from gold nanoparticles (AuNPs) in an aqueous solution, providing silver-free gold films. Chloroauric acid is reduced to AuNP building blocks by 2-(N-morpholino)ethanesulfonic acid, which also acts as a protecting agent and pH buffer. By adding potassium chloride before Au......, they can be controlled by varying the temperature, chloride concentration, ionic strength, and protonation of the buffer. cNPGF formation is attributed to the destabilization of AuNPs at the air–liquid interface. The developed method generates electrochemically stable cNPGFs up to 20 cm2 in size...

  14. Nanowire Lasers

    Directory of Open Access Journals (Sweden)

    Couteau C.

    2015-05-01

    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  15. Biomimetic Cationic Nanoparticles Based on Silica: Optimizing Bilayer Deposition from Lipid Films

    Directory of Open Access Journals (Sweden)

    Rodrigo T. Ribeiro

    2017-10-01

    Full Text Available The optimization of bilayer coverage on particles is important for a variety of biomedical applications, such as drug, vaccine, and genetic material delivery. This work aims at optimizing the deposition of cationic bilayers on silica over a range of experimental conditions for the intervening medium and two different assemblies for the cationic lipid, namely, lipid films or pre-formed lipid bilayer fragments. The lipid adsorption on silica in situ over a range of added lipid concentrations was determined from elemental analysis of carbon, hydrogen, and nitrogen and related to the colloidal stability, sizing, zeta potential, and polydispersity of the silica/lipid nanoparticles. Superior bilayer deposition took place from lipid films, whereas adsorption from pre-formed bilayer fragments yielded limiting adsorption below the levels expected for bilayer adsorption.

  16. Synthesis of Ag and Au nanoparticles embedded in carbon film: Optical, crystalline and topography analysis

    Science.gov (United States)

    Gholamali, Hediyeh; Shafiekhani, Azizollah; Darabi, Elham; Elahi, Seyed Mohammad

    2018-03-01

    Atomic force microscopy (AFM) images give valuable information about surface roughness of thin films based on the results of power spectral density (PSD) through the fast Fourier transform (FFT) algorithms. In the present work, AFM data are studied for silver and gold nanoparticles (Ag NPs a-C: H and Au NPs a-C: H) embedded in amorphous hydrogenated carbon films and co-deposited on glass substrate via of RF-Sputtering and RF-Plasma Enhanced Chemical Vapor Deposition methods. Here, the working gas is acetylene and the targets are Ag and Au. While time and power are constant, the only variable parameter in this study is initial pressure. In addition, the crystalline structure of Ag NPs a-C: H and Au NPs a-C: H are studied using X-ray diffraction (XRD). UV-visible spectrophotometry will also investigate optical properties and localized surface plasmon resonance (LSPR) of samples.

  17. ToF-SIMS study of growth behavior in all-nanoparticle multilayer films using a novel indicator layer

    International Nuclear Information System (INIS)

    Chen, B.-J.; Yin, Y.-S.; Ling, Y.-C.

    2008-01-01

    All-nanoparticle multilayer films found novel applications in the areas of photonics, catalysis, sensors, and biomaterials. The assembly of nanoparticles into conformal and uniform films with precise control over chemical and physical properties poses a significant challenge. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), we have investigated the growth behavior in all-nanoparticle multilayer films using a novel indicator layer. The all-nanoparticle multilayer films were prepared by dipping the polyester substrate with electrostatic charges alternatively into solutions containing three different types of nanoparticles (TiO 2 , Al 2 O 3 , and SiO 2 ). Upon the deposition of each layer, ToF-SIMS was employed to determine the surface chemical composition of intermediate products. The intermixing extent of TiO 2 indicator layer was used to reveal the stratification of each layer. Combining with zeta-potential measurements, the solvation and deposition of the under-layer species in the aqueous environment during fresh layer formation was proposed as a plausible cause for mutilayers not stratified into well-defined layers but displaying a nonlinear growth behavior.

  18. Hyaluronate nanoparticles included in polymer films for the prolonged release of vitamin E for the management of skin wounds.

    Science.gov (United States)

    Pereira, Gabriela Garrastazu; Detoni, Cassia Britto; Balducci, Anna Giulia; Rondelli, Valeria; Colombo, Paolo; Guterres, Silvia Stanisçuaski; Sonvico, Fabio

    2016-02-15

    Lecithin and hyaluronic acid were used for the preparation of polysaccharide decorated nanoparticles loaded with vitamin E using the cationic lipid dioctadecyldimethylammonium bromide (DODMA). Nanoparticles showed mean particle size in the range 130-350 nm and narrow size distribution. Vitamin E encapsulation efficiency was higher than 99%. These nanoparticles were incorporated in polymeric films containing Aloe vera extract, hyaluronic acid, sodium alginate, polyethyleneoxide (PEO) and polyvinylalcohol (PVA) as an innovative treatment in skin wounds. Films were thin, flexible, resistant and suitable for application on burn wounds. Additionally, in vitro occlusion study highlighted the dependence of the occlusive effect on the presence of nanoparticles. The results obtained show that the bioadhesive films containing vitamin E acetate and Aloe vera could be an innovative therapeutic system for the treatment of skin wounds, such as burns. The controlled release of the vitamin along with a reduction in water loss through damaged skin provided by the nanoparticle-loaded polymer film are considered important features for an improvement in wound healing and skin regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. A novel approach to fabricate dye-encapsulated polymeric micro- and nanoparticles by thin film dewetting technique.

    Science.gov (United States)

    Chatterjee, Manosree; Hens, Abhiram; Mahato, Kuldeep; Jaiswal, Namita; Mahato, Nivedita; Nagahanumaiah; Chanda, Nripen

    2017-11-15

    A new method is reported for fabrication of polymeric micro- and nanoparticles from an intermediate patterned surface originated by dewetting of a polymeric thin film. Poly (d, l-lactide-co-glycolide) or PLGA, a biocompatible polymer is used to develop a thin film over a clean glass substrate which dewets spontaneously in the micro-/nano-patterned surface of size range 50nm to 3.5µm. Since another water-soluble polymer, poly vinyl alcohol (PVA) is coated on the same glass substrate before PLGA thin film formation, developed micro-/nano-patterns are easily extracted in water in the form of micro- and nanoparticle mixture of size range 50nm to 3.0µm. This simplified method is also used to effectively encapsulate a dye molecule, rhodamine B inside the PLGA micro-/nanoparticles. The developed dye-encapsulated nanoparticles, PLGA-rhodamine are separated from the mixture and tested for in-vitro delivery application of external molecules inside human lung cancer cells. For the first time, the use of thin film dewetting technique is reported as a potential route for the synthesis of polymeric micro-/nanoparticles and effective encapsulation of external species therein. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Synthesis of noble metal nanoparticles and their superstructures; Darstellung von Edelmetallnanopartikeln und deren Ueberstrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Bigall, Nadja-Carola

    2009-08-18

    A modified synthesis procedure for citrate-stabilized gold nanoparticles in aqueous solution is transferred under application of equal concentrations to the systems silver, platinum, and palladium. The nanoparticles are analyzed by means of absorption spectroscopy and electron microscopy. Ordered superstructures of the noble-metal nanoparticles can be synthesized by infiltration of templates of block-copolymer films with aqueous nanoparticle solution. In dependence on the pre-treatment of the polymer films either two-dimensional periodical arrangements with a periodicity of less than 30 nm or fingerprint-like arrangements with a groove distance in the same order of magnitude. By removal of the polymer one- respectively two-dimensional arrangements of platinum nanowires respectively nanoparticles on a silicon waver arise.

  1. Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

    Directory of Open Access Journals (Sweden)

    Claes G. Granqvist

    2016-12-01

    Full Text Available Today’s advances in materials science and technology can lead to better buildings with improved energy efficiency and indoor conditions. Particular attention should be directed towards windows and glass facades—jointly known as “glazings”—since current practices often lead to huge energy expenditures related to excessive inflow or outflow of energy which need to be balanced by energy-intensive cooling or heating. This review article outlines recent progress in thermochromics, i.e., it deals with materials whose optical properties are strongly dependent on temperature. In particular, we discuss oxide-based thin surface coatings (thin films and nanoparticle composites which can be deposited onto glass and are able to regulate the throughput of solar energy while the luminous (visible properties remain more or less unaltered. Another implementation embodies lamination materials incorporating thermochromic (TC nanoparticles. The thin films and nanocomposites are based on vanadium dioxide (VO2, which is able to change its properties within a narrow temperature range in the vicinity of room temperature and either reflects or absorbs infrared light at elevated temperatures, whereas the reflectance or absorptance is much smaller at lower temperatures. The review outlines the state of the art for these thin films and nanocomposites with particular attention to recent developments that have taken place in laboratories worldwide. Specifically, we first set the scene by discussing environmental challenges and their relationship with TC glazings. Then enters VO2 and we present its key properties in thin-film form and as nanoparticles. The next part of the article gives perspectives on the manufacturing of these films and particles. We point out that the properties of pure VO2 may not be fully adequate for buildings and we elaborate how additives, antireflection layers, nanostructuring and protective over-coatings can be employed to yield improved

  2. Mixed pinning landscape in nanoparticle-introduced YGdBa2Cu3Oy films grown by metal organic deposition

    Science.gov (United States)

    Miura, M.; Maiorov, B.; Baily, S. A.; Haberkorn, N.; Willis, J. O.; Marken, K.; Izumi, T.; Shiohara, Y.; Civale, L.

    2011-05-01

    We study the field (H) and temperature (T) dependence of the critical current density (Jc) and irreversibility field (Hirr) at different field orientations in Y0.77Gd0.23Ba2Cu3Oy with randomly distributed BaZrO3 nanoparticles (YGdBCO+BZO) and YBa2Cu3Oy (YBCO) films. Both MOD films have large RE2Cu2O5 (225) nanoparticles (˜80 nm in diameter) and a high density of twin boundaries (TB). In addition, YGdBCO+BZO films have a high density of BZO nanoparticles (˜25 nm in diameter). At high temperatures (T > 40 K), the superconducting properties, such as Jc, Hirr, and flux creep rates, are greatly affected by the BZO nanoparticles, while at low temperatures the superconducting properties of both the YBCO and YGdBCO+BZO films show similar field and temperature dependencies. In particular, while the Jc of YBCO films follow a power-law dependence (∝H-α) at all measured T, this dependence is only followed at low T for YGdBCO+BZO films. As a function of T, the YGdBCO+BZO film shows Jc(T,0.01T)~[1-(T/Tc)2]n with n ˜ 1.24 ± 0.05, which points to “δTc pinning.” We analyze the role of different types of defects in the different temperature regimes and find that the strong pinning of the BZO nanoparticles yields a higher Hirr and improved Jc along the c axis and at intermediate orientations at high T. The mixed pinning landscapes due to the presence of disorder of various dimensionalities have an important role in the improvement of in-field properties.

  3. Gold catalytic Growth of Germanium Nanowires by chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    M. Zahedifar

    2013-03-01

    Full Text Available Germanium nanowires (GeNWs were synthesized using chemical vapor deposition (CVD based on vapor–liquid–solid (VLS mechanism with Au nanoparticles as catalyst and germanium tetrachloride (GeCl4 as a precursor of germanium. Au catalysts were deposited on silicon wafer as a thin film, firstly by sputtering technique and secondly by submerging the silicon substrates in Au colloidal solution, which resulted in Au nanoparticles with different sizes. GeNWs were synthesized at 400 °C, which is a low temperature for electrical device fabrication. Effect of different parameters such as Au nanoparticles size, carrier gas (Ar flow and mixture of H2 with the carrier gas on GeNWs diameter and shape was studied by SEM images. The chemical composition of the nanostructure was also examined by energy dispersive X-ray spectroscopy (EDS.

  4. An integrated buccal delivery system combining chitosan films impregnated with peptide loaded PEG-b-PLA nanoparticles.

    Science.gov (United States)

    Giovino, Concetta; Ayensu, Isaac; Tetteh, John; Boateng, Joshua S

    2013-12-01

    Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan films (Ch-films-NPs). These films were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5mg of NPs per film) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01M PBS at 37°C and texture analyzer, respectively. Formulations containing 3mg of NPs per film produced optimised films with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the films, preceding in vitro drug (insulin) release from Ch-films-NPs after 6h. Modulated release was observed with 70% of encapsulated insulin released after 360h. The use of chitosan films yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral™ buccal tissue construct relative to the pure drug. Flux and apparent permeation coefficient of 0.1μg/cm(2)/h and 4×10(-2)cm(2)/h were respectively obtained for insulin released from Ch-films-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-films-NPs was preserved during the formulation process. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Growth of Gold-assisted Gallium Arsenide Nanowires on Silicon Substrates via Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Ramon M. delos Santos

    2008-06-01

    Full Text Available Gallium arsenide nanowires were grown on silicon (100 substrates by what is called the vapor-liquid-solid (VLS growth mechanism using a molecular beam epitaxy (MBE system. Good quality nanowires with surface density of approximately 108 nanowires per square centimeter were produced by utilizing gold nanoparticles, with density of 1011 nanoparticles per square centimeter, as catalysts for nanowire growth. X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy revealed that the nanowires are epitaxially grown on the silicon substrates, are oriented along the [111] direction and have cubic zincblende structure.

  6. Functionalised zinc oxide nanowire gas sensors: Enhanced NO(2) gas sensor response by chemical modification of nanowire surfaces.

    Science.gov (United States)

    Waclawik, Eric R; Chang, Jin; Ponzoni, Andrea; Concina, Isabella; Zappa, Dario; Comini, Elisabetta; Motta, Nunzio; Faglia, Guido; Sberveglieri, Giorgio

    2012-01-01

    Surface coating with an organic self-assembled monolayer (SAM) can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx) sensor toward particular target gases in the environment. In this study the effect of an adsorbed organic layer on the dynamic response of zinc oxide nanowire gas sensors was investigated. The effect of ZnO surface functionalisation by two different organic molecules, tris(hydroxymethyl)aminomethane (THMA) and dodecanethiol (DT), was studied. The response towards ammonia, nitrous oxide and nitrogen dioxide was investigated for three sensor configurations, namely pure ZnO nanowires, organic-coated ZnO nanowires and ZnO nanowires covered with a sparse layer of organic-coated ZnO nanoparticles. Exposure of the nanowire sensors to the oxidising gas NO(2) produced a significant and reproducible response. ZnO and THMA-coated ZnO nanowire sensors both readily detected NO(2) down to a concentration in the very low ppm range. Notably, the THMA-coated nanowires consistently displayed a small, enhanced response to NO(2) compared to uncoated ZnO nanowire sensors. At the lower concentration levels tested, ZnO nanowire sensors that were coated with THMA-capped ZnO nanoparticles were found to exhibit the greatest enhanced response. ΔR/R was two times greater than that for the as-prepared ZnO nanowire sensors. It is proposed that the ΔR/R enhancement in this case originates from the changes induced in the depletion-layer width of the ZnO nanoparticles that bridge ZnO nanowires resulting from THMA ligand binding to the surface of the particle coating. The heightened response and selectivity to the NO(2) target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles.

  7. Single layer porous gold films grown at different temperatures

    International Nuclear Information System (INIS)

    Zhang Renyun; Hummelgard, Magnus; Olin, Hakan

    2010-01-01

    Large area porous gold films can be used in several areas including electrochemical electrodes, as an essential component in sensors, or as a conducting material in electronics. Here, we report on evaporation induced crystal growth of large area porous gold films at 20, 40 and 60 deg. C. The gold films were grown on liquid surface at 20 deg. C, while the films were grown on the wall of beakers when temperature increased to 40 and 60 deg. C. The porous gold films consisted of a dense network of gold nanowires as characterized by TEM and SEM. TEM diffraction results indicated that higher temperature formed larger crystallites of gold wires. An in situ TEM imaging of the coalescence of gold nanoparticles mimicked the process of the growth of these porous films, and a plotting of the coalescence time and the neck radius showed a diffusion process. The densities of these gold films were also characterized by transmittance, and the results showed film grown at 20 deg. C had the highest density, while the film grown at 60 deg. C had the lowest consistent with SEM and TEM characterization. Electrical measurements of these gold films showed that the most conductive films were the ones grown at 40 deg. C. The conductivities of the gold films were related to the amount of contamination, density and the diameter of the gold nanowires in the films. In addition, a gold film/gold nanoparticle hybrid was made, which showed a 10% decrease in transmittance during hybridization, pointing to applications as chemical and biological sensors.

  8. Magnetic core/shell nanoparticle thin films deposited by MAPLE: Investigation by chemical, morphological and in vitro biological assays

    International Nuclear Information System (INIS)

    Cristescu, R.; Popescu, C.; Socol, G.; Iordache, I.; Mihailescu, I.N.; Mihaiescu, D.E.; Grumezescu, A.M.; Balan, A.; Stamatin, I.; Chifiriuc, C.; Bleotu, C.; Saviuc, C.; Popa, M.; Chrisey, D.B.

    2012-01-01

    Highlights: ► We deposit magnetic Fe 3 O 4 /oleic acid/cephalosporin nanoparticle thin films by MAPLE. ► Thin films have a chemical structure similar to the starting material. ► Cephalosporins have an additive effect on the grain size and induce changes in grain shape. ► MAPLE can be used to develop novel strategies for fighting medical biofilms associated with chronic infections. - Abstract: We report on thin film deposition of nanostructured Fe 3 O 4 /oleic acid/ceftriaxone and Fe 3 O 4 /oleic acid/cefepime nanoparticles (core/shell/adsorption-shell) were fabricated by matrix assisted pulsed laser evaporation (MAPLE) onto inert substrates. The thin films were characterized by profilometry, Fourier transform infrared spectroscopy, atomic force microscopy, and investigated by in vitro biological assays. The biological properties tested included the investigation of the microbial viability and the microbial adherence to the glass coverslip nanoparticle film, using Gram-negative and Gram-positive bacterial strains with known antibiotic susceptibility behavior, the microbial adherence to the HeLa cells monolayer grown on the nanoparticle pellicle, and the cytotoxicity on eukaryotic cells. The proposed system, based on MAPLE, could be used for the development of novel anti-microbial materials or strategies for fighting pathogenic biofilms frequently implicated in the etiology of biofilm associated chronic infections.

  9. Large third-order optical nonlinearity in vertically oriented mesoporous silica thin films embedded with Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Min; Liu, Qiming, E-mail: qmliu@whu.edu.cn [Wuhan University, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology (China)

    2016-12-15

    Taking advantage of the channel confinement of mesoporous films to prevent the agglomeration of Ag nanoparticles to achieve large third-order optical nonlinearity in amorphous materials, Ag-loaded composite mesoporous silica film was prepared by the electrochemical deposition method on ITO substrate. Ag ions were firstly transported into the channels of mesoporous film by the diffusion and binding force of channels, which were reduced to nanoparticles by applying suitable voltage. The existence and uniform distribution of Ag nanoparticles ranging in 1–10 nm in the mesoporous silica thin films were exhibited by UV spectrophotometer, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. The third-order optical nonlinearity induced by Ag nanoparticles was studied by the Z-scan technique. Due to the local field surface plasmon resonance, the maximum third-order nonlinear optical susceptibility of Ag-loaded composite mesoporous silica film is 1.53×10{sup −10} esu, which is 1000 times larger than that of the Ag-contained chalcogenide glasses which showed large nonlinearity in amorphous materials.

  10. Magnetic core/shell nanoparticle thin films deposited by MAPLE: Investigation by chemical, morphological and in vitro biological assays

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Socol, G.; Iordache, I.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Mihaiescu, D.E.; Grumezescu, A.M. [Faculty of Applied Chemistry and Materials Science, ' Politehnica' University of Bucharest, 1-7 Polizu Street, 011061 Bucharest (Romania); Balan, A.; Stamatin, I. [University of Bucharest, 3Nano-SAE Research Center, PO Box MG-38, Bucharest-Magurele (Romania); Chifiriuc, C. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Bleotu, C. [Stefan S. Nicolau Institute of Virology, 285 Mihai Bravu, 030304 Bucharest (Romania); Saviuc, C.; Popa, M. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Chrisey, D.B. [Rensselaer Polytechnic Institute, School of Engineering, Departments of Materials Science and Biomedical Engineering, Troy, 12180-3590, NY (United States)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We deposit magnetic Fe{sub 3}O{sub 4}/oleic acid/cephalosporin nanoparticle thin films by MAPLE. Black-Right-Pointing-Pointer Thin films have a chemical structure similar to the starting material. Black-Right-Pointing-Pointer Cephalosporins have an additive effect on the grain size and induce changes in grain shape. Black-Right-Pointing-Pointer MAPLE can be used to develop novel strategies for fighting medical biofilms associated with chronic infections. - Abstract: We report on thin film deposition of nanostructured Fe{sub 3}O{sub 4}/oleic acid/ceftriaxone and Fe{sub 3}O{sub 4}/oleic acid/cefepime nanoparticles (core/shell/adsorption-shell) were fabricated by matrix assisted pulsed laser evaporation (MAPLE) onto inert substrates. The thin films were characterized by profilometry, Fourier transform infrared spectroscopy, atomic force microscopy, and investigated by in vitro biological assays. The biological properties tested included the investigation of the microbial viability and the microbial adherence to the glass coverslip nanoparticle film, using Gram-negative and Gram-positive bacterial strains with known antibiotic susceptibility behavior, the microbial adherence to the HeLa cells monolayer grown on the nanoparticle pellicle, and the cytotoxicity on eukaryotic cells. The proposed system, based on MAPLE, could be used for the development of novel anti-microbial materials or strategies for fighting pathogenic biofilms frequently implicated in the etiology of biofilm associated chronic infections.

  11. Polymer-Silica nanoparticles composite films as protective coatings for stone-based monuments

    Energy Technology Data Exchange (ETDEWEB)

    Manoudis, P [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece); Papadopoulou, S [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece); Karapanagiotis, I [' Ormylia' Art Diagnosis Centre, Ormylia, Chalkidiki, 63071 (Greece); Tsakalof, A [Medical Department, University of Thessaly, Larissa, 41222 (Greece); Zuburtikudis, I [Department of Industrial Design Engineering, TEI of Western Macedonia, Kozani, 50100 (Greece); Panayiotou, C [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece)

    2007-04-15

    The decrease of surface energy of mineral substrates similar to those used in many stone monuments of cultural heritage by the application of protective polymer coatings along with the simultaneous increase of their surface roughness can increase their ability to repel water substantially. In this work, the effect of artificially induced roughness on the water repellency of mineral substrates coated with protective polymer films was investigated. Natural marble samples or home made calcium carbonate blocks were tried as the mineral substrates. The roughness increase was achieved by mineral chemical etching or by creation of nanoscale binary composition film on the substrate surface. PMMA and PFPE were the polymers used, while different-sized silica nanoparticles were employed for the production of the nanocomposite films. Examination of the coated and uncoated surfaces with profilometry and AFM and measurements of water contact angles reveal a pronounced effect of the surface roughness on water repellency. Especially in the case of nanocomposite coatings, the surfaces become super-hydrophobic. This result indicates that the nanoscale binary composition film scheme, which is characterized by its simplicity and low cost, is a suitable candidate for the water protection of stone-based monuments on large scale.

  12. Polymer-Silica nanoparticles composite films as protective coatings for stone-based monuments

    International Nuclear Information System (INIS)

    Manoudis, P; Papadopoulou, S; Karapanagiotis, I; Tsakalof, A; Zuburtikudis, I; Panayiotou, C

    2007-01-01

    The decrease of surface energy of mineral substrates similar to those used in many stone monuments of cultural heritage by the application of protective polymer coatings along with the simultaneous increase of their surface roughness can increase their ability to repel water substantially. In this work, the effect of artificially induced roughness on the water repellency of mineral substrates coated with protective polymer films was investigated. Natural marble samples or home made calcium carbonate blocks were tried as the mineral substrates. The roughness increase was achieved by mineral chemical etching or by creation of nanoscale binary composition film on the substrate surface. PMMA and PFPE were the polymers used, while different-sized silica nanoparticles were employed for the production of the nanocomposite films. Examination of the coated and uncoated surfaces with profilometry and AFM and measurements of water contact angles reveal a pronounced effect of the surface roughness on water repellency. Especially in the case of nanocomposite coatings, the surfaces become super-hydrophobic. This result indicates that the nanoscale binary composition film scheme, which is characterized by its simplicity and low cost, is a suitable candidate for the water protection of stone-based monuments on large scale

  13. Optical and electrical characterizations of nanoparticle Cu2S thin films

    International Nuclear Information System (INIS)

    Saadeldin, M.; Sawaby, K.; Soliman, H. S.; Ali, H. A. M.

    2014-01-01

    Copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite (γ-Cu 2 S) phase. The atomic force microscopy images indicate that the film exhibits nanoparticles with an average size of nearly 44 nm. Specrtophotometric measurements for the transmittance and reflectance are carried out at normal incidence in a spectral wavelength range of 450 nm–2500 nm. The refractive index, n, as well as the absorption index, k is calculated. Some dispersion parameters are determined. The analyses of ε 1 and ε 2 reveal several absorption peaks. The analysis of the spectral behavior of the absorption coefficient, α, in the absorption region reveals direct and indirect allowed transitions. The dark electrical resistivity is studied as a function of film thickness and temperature. Tellier's model is adopted for determining the mean free path and bulk resistance. (condensed matter: structural, mechanical, and thermal properties)

  14. Gold nanoparticle-polydimethylsiloxane films reflect light internally by optical diffraction and Mie scattering

    International Nuclear Information System (INIS)

    Dunklin, Jeremy R; Keith Roper, D; Forcherio, Gregory T

    2015-01-01

    Optical properties of polymer films embedded with plasmonic nanoparticles (NPs) are important in many implementations. In this work, optical extinction by polydimethylsiloxane (PDMS) films containing gold (Au) NPs was enhanced at resonance compared to AuNPs in suspensions, Beer–Lambert law, or Mie theory by internal reflection due to optical diffraction in 16 nm AuNP–PDMS films and Mie scattering in 76 nm AuNP–PDMS films. Resonant extinction per AuNP for 16 nm AuNPs with negligible resonant Mie scattering was enhanced up to 1.5-fold at interparticle separation (i.e., Wigner–Seitz radii) comparable to incident wavelength. It was attributable to diffraction through apertures formed by overlapping electric fields of adjacent, resonantly excited AuNPs at Wigner–Seitz radii equal to or less than incident wavelengths. Resonant extinction per AuNP for strongly Mie scattering 76 nm AuNPs was enhanced up to 1.3-fold at Wigner–Seitz radii four or more times greater than incident wavelength. Enhanced light trapping from diffraction and/or scattering is relevant to optoelectronic, biomedical, and catalytic activity of substrates embedded with NPs. (paper)

  15. Transparent Conducting Film Fabricated by Metal Mesh Method with Ag and Cu@Ag Mixture Nanoparticle Pastes

    Directory of Open Access Journals (Sweden)

    Hyun Min Nam

    2017-05-01

    Full Text Available Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs, flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO shows high transmittance (90% at low sheet resistance (50 Ω/cm2. However, ITO films lack mechanical flexibility, especially under bending stress, and have limitation in application to large-area TSPs (over 15 inches due to the trade-off in high transmittance and low sheet resistance properties. One promising solution is to use metal mesh-type transparent conducting film, especially for touch panel application. In this work, we investigated such inter-related issues as UV imprinting process to make a trench layer pattern, the synthesis of core-shell-type Ag and Cu@Ag composite nanoparticles and their paste formulation, the filling of Ag and Cu@Ag mixture nanoparticle paste to the trench layer, and touch panel fabrication processes.

  16. Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO{sub 3} film by decorating with Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qing; Shen, Mingrong; Fang, Liang, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Zhou, Yang; You, Lu; Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore 639798 (Singapore)

    2016-01-11

    Polycrystalline BiFeO{sub 3} (BFO) films are fabricated on Pt/Ti/SiO{sub 2}/Si(100) substrate as photoelectrode using sol-gel method. The microstructure, optical, and photoelectrochemical (PEC) properties of the films are characterized and optimized by controlling the film thickness. Moreover, the PEC properties of the BFO films are dependent on ferroelectric polarization, which is mainly ascribed to the modulation of band structure at the BFO/electrolyte interface by the polarization. Further enhancement of PEC properties is obtained by decorating the samples with appropriate amounts of Ag nanoparticles, which is attributed to the reduced electron-hole recombination, and localized surface plasmon resonance effect of Ag nanoparticles.

  17. Au/SiO2 nanocomposite film substrates with a high number density of Au