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Sample records for silica-titania gel films

  1. Stability of erbium and silver implanted in silica-titania sol-gel films

    International Nuclear Information System (INIS)

    Ramos, A.R.; Marques, C.; Alves, E.; Marques, A.C.; Almeida, R.M.

    2005-01-01

    We implanted silica-titania sol-gel films with 3 x 10 15 at./cm 2 , 180 keV Er + and 6 x 10 16 at./cm 2 , 140 keV Ag + ions. The energies were chosen so that the profiles of Ag and Er overlap. RBS and ERDA were used to study the behaviour of Ag, Er and H during the heat treatments used to density the films. Implantation causes H depletion at the film surface and an increase in H concentration just beneath the implanted Ag and Er profiles. The total H content decreases by 27% to 75% during implantation. During annealing the H content decreases, with an almost complete H loss after annealing for 35 min at 800 deg. C. The Ag profile remains stable up to 600 deg. C. Above 700 deg. C Ag becomes increasingly mobile. Annealing at 800 deg. C for 35 min results in a nearly constant Ag distribution in the film. The Er profile remains unchanged with heat treatment up to the maximum temperature used (800 deg. C)

  2. Formation of bimodal porous silica-titania monoliths by sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Ruzimuradov, O N, E-mail: ruzimuradov@rambler.ru [Department of General Chemistry, Faculty of Chemistry, National University of Uzbekistan, 15, Vuzgorodok, Tashkent, 100174 (Uzbekistan)

    2011-10-29

    Silica-titania monoliths with micrometer-scale macroporous and nanometer-scale mesoporous structure and high titania contents are prepared by sol-gel process and phase separation. Titanium alkoxide precursor was not effective in the preparation of high titania content composites because of strong decrease in phase separation tendency. Bimodal porous gels with high titania content were obtained by using inorganic salt precursors such as titanium sulfate and titanium chloride. Various characterization techniques, including SEM, XRD, Hg porosimetry and N{sub 2} adsorption have been carried out to investigate the formation process and physical-chemical properties of silica-titania monoliths. The characterization results show that the silica-titania monoliths possess a bimodal porous structure with well-dispersed titania inside silica network. The addition of titania in silica improves the thermal stability of both macroporous and mesoporous structures.

  3. Preparation and Characterization of Highly Spherical Silica-titania Aerogel Beads with High Surface Area

    Directory of Open Access Journals (Sweden)

    YU Yu-xi

    2017-02-01

    Full Text Available The silica-titania aerogel beads were synthesized through sol-gel reaction followed by supercritical drying, in which TEOS and TBT as co-precursors, EtOH as solvents, HAC and NH3·H2O as catalysts. The as-prepared aerogel beads were characterized by SEM,TEM,XRD,FT-IR,TG-DTA and nitrogen adsorption-desorption. The results indicate that the diameter distribution of beads are between 1-8mm, the average diameter of beads is 3.5mm. The aerogel beads have nanoporous network structure with high specific surface area of 914.5m2/g, and the TiO2 particles are distributed in the aerogel uniformly, which keep the anatase crystal under high temperature.

  4. The Effect of Titanium Tetrahedral Coordination of Silica-Titania Catalyst on the Physical Properties of Biodiesel

    Science.gov (United States)

    Nizar, U. K.; Hidayatul, J.; Sundari, R.; Bahrizal, B.; Amran, A.; Putra, A.; Latisma DJ, L.; Dewata, I.

    2018-04-01

    This study investigates the correlation of the number of titanium tetrahedral coordination and biodiesel production. The solid-state method has been used to synthesis of silica-titania catalyst for biodiesel production, which the precursors, i.e. silica and titania commercials were heated in the temperature range of 450 - 550°C. The characterization of the prepared silica-titania has been studied by FTIR and DR UV-Vis in order to identify and calculate the presence of titanium tetrahedral coordination in silica-titania catalyst. A very small peak at around 950 cm-1 indicated the presence of titanium tetrahedral coordination through Si–O–Ti bonds. Deconvolution of DR UV-Vis spectra showed the coordination of titanium in silica-titania is more octahedral. However, the number of titanium tetrahedral coordination of the prepared silica-titania is found higher than that of TiO2 commercial. The increasing of titanium tetrahedral fraction in silica-titania affects the physical properties of biodiesel in terms of boiling point, viscosity and density, which is produced by the reaction of methanol and palm oil.

  5. Fabrication of Magnetite/Silica/Titania Core-Shell Nanoparticles

    Directory of Open Access Journals (Sweden)

    Suh Cem Pang

    2012-01-01

    Full Text Available Fe3O4/SiO2/TiO2 core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4 nanoparticles were being encapsulated within discrete silica nanospheres, and a layer of TiO2 shell was then coated directly onto each silica nanosphere. As-synthesized Fe3O4/SiO2/TiO2 core-shell nanoparticles showed enhanced photocatalytic properties as evidenced by the enhanced photodegradation of methylene blue under UV light irradiation.

  6. Sustainability of the Catalytic Activity of a Silica-Titania Composite (STC) for Long-Term Indoor Air Quality Control

    Science.gov (United States)

    Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.

    2011-01-01

    TiO2-assisted photocatalytic oxidation (PCO) is an emerging technology for indoor air quality control and is also being evaluated as an alternative trace contaminant control technology for crew habitats in space exploration. Though there exists a vast range of literature on the development of photocatalysts and associated reactor systems, including catalyst performance and performance-influencing factors, the critical question of whether photocatalysts can sustain their initial catalytic activity over an extended period of operation has not been adequately addressed. For a catalyst to effectively serve as an air quality control product, it must be rugged enough to withstand exposure to a multitude of low concentration volatile organic compounds (VOCs) over long periods of time with minimal loss of activity. The objective of this study was to determine the functional lifetime of a promising photocatalyst - the silica-titania composite (STC) from Sol Gel Solutions, LLC in a real-world scenario. A bench-scale STC-packed annular reactor under continuous irradiation by a UV-A fluorescent black-light blue lamp ((lambda)max = 365 nm) was exposed to laboratory air continuously at an apparent contact time of 0.27 sand challenged with a known concentration of ethanol periodically to assess any changes in catalytic activity. Laboratory air was also episodically spiked with halocarbons (e.g., octafluoropropane), organosulfur compounds (e.g., sulfur hexafluoride), and organosilicons (e.g., siloxanes) to simulate accidental releases or leaks of such VOCs. Total organic carbon (TOC) loading and contaminant profiles of the laboratory air were also monitored. Changes in STC photocatalytic performance were evaluated using the ethanol mineralization rate, mineralization efficiency, and oxidation intermediate (acetaldehyde) formation. Results provide insights to any potential catalyst poisoning by trace halocarbons and organosulfur compounds.

  7. Silica-titania xerogel for solid phase spectrophotometric determination of salicylate and its derivatives in biological liquids and pharmaceuticals.

    Science.gov (United States)

    Morosanova, Maria A; Morosanova, Elena I

    2015-01-01

    Salicylic acid and its derivatives are widely used drugs with potential toxicity. The main areas of salicylate derivatives determination are biological liquids and pharmaceuticals analysis. Silica-titania xerogel has been used for solid phase spectrophotometric determination of various salicylate derivatives (salicylate, salicylamide, methylsalicylate). The reaction conditions influence on the interaction of salicylate derivatives with silica-titania xerogels has been investigated; the characteristics of titanium(IV)-salicylate derivatives complexes in solid phase have been described. The simple solid phase spectrophotometric procedures are based on the formation of xerogel incorporated titanium(IV) colored complexes with salicylate derivatives. A linear response has been observed in the following concentration ranges 0.1-5, 0.5-10 and 0.05-4.7 mM for salicylate, salicylamide, and methylsalicylate, respectively. The proposed procedures have been applied to the analysis of human urine, synthetic serum, and pharmaceuticals. The simple solid phase spectrophotometric procedures of salicylate derivatives determination based on the new sensor materials have been proposed for biological liquids and pharmaceuticals analysis. Graphical abstractComplexation of titanium (IV), incorporated in silica-titania xerogels (Si-Ti), with salicylate derivatives (L) resulting in yellow-colored xerogels (Si-Ti/Ln) has been proposed for salicylate derivatives determination in biological liquids and pharmaceuticals.

  8. Silica-Titania Composite (STC)'s Performance in the Photocatalytic Oxidation of Polar VOCs

    Science.gov (United States)

    Levine, Lanfang H.; Coutts, Janelle; Richards, Jeffrey; Mazyck, David; Mazyck, David

    2011-01-01

    The objective of this paper is to determine the performance of a Silica-Titania Composite (STC) in the photocatalytic oxidation (PCO) of polar VOCs for potential applications in trace contaminant control within space habitats such as the ISS and CEV Orion. Tests were carried out in a bench scale STC-packed annular reactor under continuous illumination by either a UV-C germicidal lamp(lambda (sub max) = 254 nm) or UV-A fluorescent BLB (lambda(sub max) = 365 nm) for the removal of ethanol (a predominant polar VOC in the ISS cabin). The STC's performance was evaluated in terms of the ethanol mineralization rate, mineralization efficiency, and the extent of its oxidation intermediate (acetaldehyde) formation in response to the type of light source (photon energy and photon flux) and relative humidity (RH) implemented. Results demonstrated that acetaldehyde was the only quantifiable intermediate in the effluent under UV illumination, but was not found in the dark adsorption experiments. The mineralization rate increased with an increase in photon energy (UV-C greater than UV-A), even though both lamps were adjusted to emit the same incident photon flux, and also increased with increasing photon flux. However, photonic efficiency decreased as the photon flux increased. More importantly, a higher photon flux gave rise to a lower effluent acetaldehyde concentration. The effect of RH on PCO was complex and intriguing because it affected both physical adsorption and photocatalytic oxidation. In general, increasing RH caused a decrease in adsorption capacity for ethanol and reduced the mineralization efficiency with a concomitant higher acetaldehyde evolution rate. The effect of RH was less profound than that of photon flux.

  9. On the morphology and potential application of polydimethylsiloxane-silica-titania composites

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available Polydimethylsiloxane-α,ω-diol was used as matrix for the preparation of polysiloxane-SiO2-TiO2 composites through in situ incorporation of silica and titania using a solvent-free sol-gel procedure. For this purpose, oxide precursors tetraethyl-orthosilicate and tetrabutyl-orthotitanate, and a proper condensation catalyst, viz. dibuthyltin dilaurate, were added in pre-established amounts to the polymer. The hydrolysis and condensation reactions take place under mild conditions, with the formation of silicon and titanium oxide networks and polymer crosslinking. The effect of SiO2 and TiO2 mass ratio on the morphology of the composites was investigated by scanning electron microscopy (SEM and X-rays diffraction (XRD, and interpreted in correlation with differential scanning calorimetry (DSC and energy-dispersive X-ray spectroscopy (EDX data. The film samples were tested as active elements in actuation devices.

  10. The Effect of Photon Source on Heterogeneous Photocatalytic Oxidation of Ethanol by a Silica-Titania Composite

    Science.gov (United States)

    Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Mazyck, David W.

    2011-01-01

    The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp ((gamma)max=365 nm) at its maximum light intensity or a UV-C germicidal lamp ((gamma)max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM/s) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 (mu)mol/photons). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

  11. Enhanced Electroresponse of Alkaline Earth Metal-Doped Silica/Titania Spheres by Synergetic Effect of Dispersion Stability and Dielectric Property.

    Science.gov (United States)

    Yoon, Chang-Min; Lee, Seungae; Cheong, Oug Jae; Jang, Jyongsik

    2015-09-02

    A series of alkaline earth metal-doped hollow SiO2/TiO2 spheres (EM-HST) are prepared as electrorheological (ER) materials via sonication-mediated etching method with various alkaline earth metal hydroxides as the etchant. The EM-HST spheres are assessed to determine how their hollow interior and metal-doping affects the ER activity. Both the dispersion stability and the dielectric properties of these materials are greatly enhanced by the proposed one-step etching method, which results in significant enhancement of ER activity. These improvements are attributed to increased particle mobility and interfacial polarization originating from the hollow nature of the EM-HST spheres and the effects of EM metal-doping. In particular, Ca-HST-based ER fluid exhibits ER performance which is 7.1-fold and 3.1-fold higher than those of nonhollow core/shell silica/titania (CS/ST) and undoped hollow silica/titania (HST)-based ER fluids, respectively. This study develops a versatile and simple approach to enhancing ER activity through synergetic effects arising from the combination of dispersion stability and the unique dielectric properties of hollow EM-HST spheres. In addition, the multigram scale production described in this experiment can be an excellent advantage for practical and commercial ER application.

  12. Photoluminescence of Titanium-Doped Zinc Orthosilicate Phosphor Gel Films

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Mu-Tsun; Wu, Jun-Min; Lin, Jian-You [Department of Materials Science and Engineering, National Formosa University, PO Box 385 Douliu, Yunlin 640, Taiwan (China); Lu, Fu-Hsing; Wang, Yen-Kai, E-mail: mttsai@ms23.hinet.net [Department of Materials Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China)

    2011-10-29

    Titanium-doped zinc orthosilicate ({alpha}-Zn{sub 2}SiO{sub 4}:Ti) phosphor thin films were deposited on silicon wafer substrates by the sol-gel process. The crystallization processes and photoluminescence properties of the films were investigated. X-ray diffraction revealed that the dried films were amorphous and converted into single-phase willemite structure following annealed at 600 deg. C and above. Upon thermal annealing at 800 deg. C - 1000 deg. C, Ti-doped willemite thin films had the average crystallite sizes of 17{approx}28 nm. The luminescence properties of phosphor films were characterized by excitation and emission spectra. Photoluminescence spectra of Ti-doped films exhibited prominent blue emission bands centered at 402 nm under an excitation wavelength of 225 nm. The emission intensity was dependent on the level of titanium doping, annealing temperature, and film thickness.

  13. Sol-gel derived ceramic electrolyte films on porous substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kueper, Timothy Walter [Univ. of California, Berkeley, CA (United States)

    1992-05-01

    A process for the deposition of sol-gel derived thin films on porous substrates has been developed; such films should be useful for solid oxide fuel cells and related applications. Yttria-stabilized zirconia films have been formed from metal alkoxide starting solutions. Dense films have been deposited on metal substrates and ceramic substrates, both dense and porous, through dip-coating and spin-coating techniques, followed by a heat treatment in air. X-ray diffraction has been used to determine the crystalline phases formed and the extent of reactions with various substrates which may be encountered in gas/gas devices. Surface coatings have been successfully applied to porous substrates through the control of substrate pore size and deposition parameters. Wetting of the substrate pores by the coating solution is discussed, and conditions are defined for which films can be deposited over the pores without filling the interiors of the pores. Shrinkage cracking was encountered in films thicker than a critical value, which depended on the sol-gel process parameters and on the substrate characteristics. Local discontinuities were also observed in films which were thinner than a critical value which depended on the substrate pore size. A theoretical discussion of cracking mechanisms is presented for both types of cracking, and the conditions necessary for successful thin formation are defined. The applicability of these film gas/gas devices is discussed.

  14. Fabrication of barium- and strontium-doped silica/titania hollow nanoparticles and their synergetic effects on promoting neuronal differentiation by activating ERK and p38 pathways.

    Science.gov (United States)

    Kim, Sojin; Jang, Yoonsun; Oh, Wan-Kyu; Kim, Chanhoi; Jang, Jyongsik

    2014-07-01

    Pristine, barium-doped, and strontium-doped hollow nanoparticles (p-HNPs, Ba-HNP, and Sr-HNP; HNPs) are prepared by sonication-mediated etching and redeposition (SMER) method and alkali-earth-metal hydroxide solution treatment. The HNPs are investigated to facilitate synergetic neuronal differentiation through alkali-earth-metal doping and in conjunction with nerve growth factor (NGF). PC12 cells are used as model cells for neuronal differentiation. The differentiation efficiency is improved in the presence of the HNPs+NGF, and the neurite length is in the order of Sr-HNP+NGF > Ba-HNP+NGF > p-HNP+NGF > NGF. Silica/titania have increasing effect on both differentiation efficiency and neurite length, and doped barium/strontium influences additional elongation of the average neurite length. Take advantage of hollow structure, NGF is encapsulated into HNPs, and they are further applied for directly inducing differentiation. The maximum differentiation efficiency is 67% in presence of the NGF-encapsulated Sr-HNP, which was 1.3 times higher than previous research. Furthermore, the neurite length is also 2.7 times higher than MnO2 decorated poly(3,4-ethylenedioxythiophene) nanoellipsoids. Ba- and Sr-HNP may offer a possibility for novel application of metal-hybrid nanomaterials for cell differentiation, and can be expanded to other cellular applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Sol-gel preparation of silica and titania thin films

    Science.gov (United States)

    Thoř, Tomáš; Václavík, Jan

    2016-11-01

    Thin films of silicon dioxide (SiO2) and titanium dioxide (TiO2) for application in precision optics prepared via the solgel route are being investigated in this paper. The sol-gel process presents a low cost approach, which is capable of tailoring thin films of various materials in optical grade quality. Both SiO2 and TiO2 are materials well known for their application in the field of anti-reflective and also highly reflective optical coatings. For precision optics purposes, thickness control and high quality of such coatings are of utmost importance. In this work, thin films were deposited on microscope glass slides substrates using the dip-coating technique from a solution based on alkoxide precursors of tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TIP) for SiO2 and TiO2, respectively. As-deposited films were studied using spectroscopic ellipsometry to determine their thickness and refractive index. Using a semi-empirical equation, a relationship between the coating speed and the heat-treated film thickness was described for both SiO2 and TiO2 thin films. This allows us to control the final heat-treated thin film thickness by simply adjusting the coating speed. Furthermore, films' surface was studied using the white-light interferometry. As-prepared films exhibited low surface roughness with the area roughness parameter Sq being on average of 0.799 nm and 0.33 nm for SiO2 and TiO2, respectively.

  16. Formation and prevention of fractures in sol-gel-derived thin films

    NARCIS (Netherlands)

    Kappert, Emiel; Pavlenko, Denys; Malzbender, J.; Nijmeijer, Arian; Benes, Nieck Edwin; Tsai, Peichun Amy

    2015-01-01

    Sol–gel-derived thin films play an important role as the functional coatings for various applications that require crack-free films to fully function. However, the fast drying process of a standard sol–gel coating often induces mechanical stresses, which may fracture the thin films. An experimental

  17. Sol-gel coated ion sources for liquid chromatography-direct electron ionization mass spectrometry.

    Science.gov (United States)

    Riboni, Nicolò; Magrini, Laura; Bianchi, Federica; Careri, Maria; Cappiello, Achille

    2017-07-25

    Advances in interfacing liquid chromatography and electron ionization mass spectrometry are presented. New ion source coatings synthesized by sol-gel technology were developed and tested as vaporization surfaces in terms of peak intensity, peak width and peak delay for the liquid chromatography-direct electron ionization mass spectrometry (Direct-EI) determination of environmental pollutants like polycyclic aromatic hydrocarbons and steroids. Silica-, titania-, and zirconia-based coatings were sprayed inside the stainless steel ion source and characterized in terms of thermal stability, film thickness and morphology. Negligible weight losses until 350-400 °C were observed for all the materials, with coating thicknesses in the 6 (±1)-11 (±2) μm range for optimal ionization process. The best performances in terms of both peak intensity and peak width were obtained by using the silica-based coating: the detection of the investigated compounds was feasible at low ng μl -1 levels with a good precision (RSD < 9% for polycyclic aromatic hydrocarbons and <11% for hormones). Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Influence of p H on optical properties of nano structure sol-gel-derived silica films

    International Nuclear Information System (INIS)

    Heshmatpuor, F.; Adelkhani, H.; Nahavandi, M.; Noorbakhsh Shourabadi, M.

    2006-01-01

    Sol-gel derived silica films were fabricated by dip-coating onto glass microscope substrates. Film properties such as transmission and surface morphology were monitored as function of dip speed and sol p H. Film transmission was increased with increasing of p H in visible range. The surface morphology of films were investigated with scanning electron microscopy.

  19. Dielectric Measurements on Sol-Gel Derived Titania Films

    Science.gov (United States)

    Capan, Rifat; Ray, Asim K.

    2017-11-01

    Alternating current (AC) impedance measurements were performed on 37 nm thick nanostructured sol-gel derived anatase titania films on ultrasonically cleaned (100) p-silicon substrates at temperatures T ranging from 100 K to 300 K over a frequency range between 20 Hz and 1 MHz. The frequency-dependent behavior of the AC conductivity σ ac( f, T) obeys the universal power law, and the values of the effective hopping barrier and hopping distance were found to be 0.79 eV and 6.7 × 10-11 m from an analysis due to the correlated barrier-hopping model. The dielectric relaxation was identified as a thermally activated non-Debye process involving an activation energy of 41.5 meV.

  20. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy

    Science.gov (United States)

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K.; Li, Jiangyu; Zhou, Qifa

    2013-01-01

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate–lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films. PMID:23798771

  1. Anion embedded sol-gel films on Al for corrosion protection

    International Nuclear Information System (INIS)

    Sheffer, Mari; Groysman, Alec; Starosvetsky, David; Savchenko, Natali; Mandler, Daniel

    2004-01-01

    We report here on the successful incorporation of organic anions into a sol-gel film on Al as a means of enhancing the protection against corrosion. Following our previous study where we showed that hydrophobic sol-gel films provided pronounced corrosion inhibition, we studied the corrosion inhibition that phenylphosphonic acid (PPA) has when embedded inside a thin sol-gel coating on Al. The anion of this organic anion tends to stay inside a phenyltrimethoxysilane (PTMOS) based sol-gel film due to π-interactions. Our findings, which are derived primarily from potentiodynamic polarization measurements, electrochemical noise, scanning electron microscopy measurements and Auger electron spectroscopy (AES), clearly show that the organic phosphonate adds to the protection efficiency of the sol-gel film

  2. Formulation of mefenamic acid loaded transfersomal gel by thin film hydration technique and hand shaking method

    Directory of Open Access Journals (Sweden)

    Krishna Sailaja

    2017-04-01

    Full Text Available Objective(s: The aim of present study is to formulate mefenamic acid transdermal gel based on vesicular drug delivery approaches.Materials and Methods: For the preparation of mefenamic acid transdermal gel, transfersomes were selected as colloidal carriers. Transfersomes were prepared by hand shaking and thin film hydration techniques. The obtained transfersomes were characterized for vesicular diameter, zeta potential, drug content, entrapment efficiency and in vitro diffusion studies.Results: Among Different formulations of transfersomes, T10(prepared by thin film hydration and containing soya lecithin: span60 ratio 1:2 was considered as the best formulation because of its mean vesicular diameter of 369 nm, zeta potential of -14 mV, drug content of 99.6%, entrapment efficiency of 84.4%, and sustained drug release of 93.3% after 12 h.T10 formulation was incorporated into gel. Comparative study was made among plain gel, and transfersomal gel. Among these two gels, transfersomal gel considered as best because of its highest drug content (91%, spreadability (43.5 g.cm/sec, pH (6.9 and sustained drug release profile for 12 h.Conclusion: By comparing  hand shaking and thin film hydration techniques, it was found thin film hydration technique produced better results and transfersomal gel was indicated better results than plain gel.

  3. Sol-gel silica films embedding NIR- emitting Yb-quinolinolate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Figus, Cristiana, E-mail: cristiana.figus@dsf.unica.it; Quochi, Francesco, E-mail: cristiana.figus@dsf.unica.it; Piana, Giacomo; Saba, Michele; Mura, Andrea; Bongiovanni, Giovanni [Dipartimento di Fisica, University of Cagliari, SS 554 Bivio per Sestu, I-09042, Monserrato-Cagliari (Italy); Artizzu, Flavia [Dipartimento di Fisica, University of Cagliari and Dipartimento di Scienze Chimiche e Geologiche, University of Cagliari, SS 554 Bivio per Sestu, I-09042, Monserrato-Cagliari (Italy); Mercuri, Maria Laura; Serpe, Angela; Deplano, Paola [Dipartimento di Scienze Chimiche e Geologiche, University of Cagliari, SS 554 Bivio per Sestu, I-09042, Monserrato-Cagliari (Italy)

    2014-10-21

    Sol-gel silica thin films embedding an ytterbium quinolinolato complex (YbClQ{sub 4}) have been obtained using different alkoxides. Homogeneous, crack- and defect-free thin films of optical quality have been successfully deposited on glass substrate by dip-coating. The silica thin films have been characterized by time-resolved photoluminescence. The luminescence properties of the YbClQ{sub 4} are preserved in silica films prepared through an optimized sol-gel approach. The excited state lifetime of the lanthanide is comparable to those observed in bulk and longer than the corresponding ones in solution.

  4. Alcohol sensing of tin oxide thin film prepared by sol–gel process

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The present paper describes the alcohol sensing characteristics of spin coated SnO2 thin film deposited by using sol–gel process. The sensitivity of the film was measured at different temperatures and different concentrations of alcohol at ppm level. Alcohol detection result shows peak sensitivity at 623 K. The.

  5. Infrared wire-grid polarizer with sol-gel antireflection films on both sides

    Science.gov (United States)

    Yamada, Itsunari; Ishihara, Yoshiro

    2017-12-01

    We fabricated an infrared wire-grid polarizer with the high transverse magnetic (TM) polarization transmittance and high extinction ratio by soft imprint lithography, sol-gel method, and Al shadow coating processes. A zilconia film was coated on Si substrate by using sol-gel method and spin coating method. Then, sol-gel zirconia grating was formed on the back side using imprinting using a silicone mold. The polarizer was produced by depositing Al obliquely on the grating. The TM transmittance of the fabricated element was greater than 80% at a wavelength of 4.8 μm. The sol-gel zilconia films acted as antireflection films. The extinction ratio exceeded 26 dB at its wavelength.

  6. Solvent-Assisted Gel Printing for Micropatterning Thin Organic-Inorganic Hybrid Perovskite Films.

    Science.gov (United States)

    Jeong, Beomjin; Hwang, Ihn; Cho, Sung Hwan; Kim, Eui Hyuk; Cha, Soonyoung; Lee, Jinseong; Kang, Han Sol; Cho, Suk Man; Choi, Hyunyong; Park, Cheolmin

    2016-09-27

    While tremendous efforts have been made for developing thin perovskite films suitable for a variety of potential photoelectric applications such as solar cells, field-effect transistors, and photodetectors, only a few works focus on the micropatterning of a perovskite film which is one of the most critical issues for large area and uniform microarrays of perovskite-based devices. Here we demonstrate a simple but robust method of micropatterning a thin perovskite film with controlled crystalline structure which guarantees to preserve its intrinsic photoelectric properties. A variety of micropatterns of a perovskite film are fabricated by either microimprinting or transfer-printing a thin spin-coated precursor film in soft-gel state with a topographically prepatterned elastomeric poly(dimethylsiloxane) (PDMS) mold, followed by thermal treatment for complete conversion of the precursor film to a perovskite one. The key materials development of our solvent-assisted gel printing is to prepare a thin precursor film with a high-boiling temperature solvent, dimethyl sulfoxide. The residual solvent in the precursor gel film makes the film moldable upon microprinting with a patterned PDMS mold, leading to various perovskite micropatterns in resolution of a few micrometers over a large area. Our nondestructive micropatterning process does not harm the intrinsic photoelectric properties of a perovskite film, which allows for realizing arrays of parallel-type photodetectors containing micropatterns of a perovskite film with reliable photoconduction performance. The facile transfer of a micropatterned soft-gel precursor film on other substrates including mechanically flexible plastics can further broaden its applications to flexible photoelectric systems.

  7. The influence of Aloe vera gel incorporation on the physicochemical and mechanical properties of banana starch-chitosan edible films.

    Science.gov (United States)

    Pinzon, Magda I; Garcia, Omar R; Villa, Cristian C

    2018-01-27

    Aloe vera (AV) gel is a promising material in food conservation, given its widely reported antimicrobial and antioxidant activity; however, its application in the formation of edible films and coatings has been small owing its low film-forming capability. The aim of this study was to investigate the physicochemical properties of film-forming solutions and films prepared using unripe banana starch-chitosan and AV gel at different AV gel concentrations. Our results showed that AV gel considerably affected the rheological and optical properties of the edible coatings, mainly due to increased amounts of solids brought by the AV gel. Film-forming capacity and physicochemical properties were also studied; most of the film properties were affected by the inclusion of AV gel, with decreased water vapor permeability, tensile strength and elongation at break. Fourier transform infrared studies showed that the inclusion of AV gel disrupts the interaction between starch and chitosan molecules; however, further studies are needed to fully understand the specific interactions between the components of AV gel and both starch and chitosan molecules. Our results suggest that the addition of AV gel creates a crosslinking effect between the phenolic compounds in AV gel and starch molecules, which disrupts the starch-chitosan interaction and greatly affects the properties of both the film-forming solution and edible films. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  8. Bactericidal micron-thin sol-gel films prevent pin tract and periprosthetic infection.

    Science.gov (United States)

    Qu, Haibo; Knabe, Christine; Burke, Megan; Radin, Shula; Garino, Jonathan; Schaer, Thomas; Ducheyne, Paul

    2014-08-01

    Orthopedic injuries constitute the majority of wounds sustained by U.S. soldiers in recent conflicts. The risk of infection is considerable with fracture fixation devices. In this pilot study, we examined the use of unique bactericidal micron-thin sol-gel films on fracture fixation devices and their ability to prevent and eradicate infections. External fixation was studied with micron-thin sol-gel coated percutaneous pins releasing triclosan and inserted medially into rabbit tibiae. A total of 11 rabbits received percutaneous pins that were either uncoated or sol-gel/triclosan coated. Internal fracture fixation was also studied using sol-gel coated intramedullary (IM) nails releasing vancomycin in the intramedullary tibiae. Six sheep received IM nails that were coated with a sol-gel film that either contained vancomycin or did not contain vancomycin. All animals were challenged with Staphylococcus aureus around the implant. Animals were euthanized at 1 month postoperative. Rabbits receiving triclosan/sol-gel coated percutaneous pins did not show signs of infection. Uncoated percutaneous pins had a significantly higher infection rate. In the sheep study, there were no radiographic signs of osteomyelitis with vancomycin/sol-gel coated IM nails, in contrast to the observations in the control cohort. Hence, the nanostructured sol-gel controlled release technology offers the promise of a reliable and continuous delivery system of bactericidals from orthopedic devices to prevent and treat infection. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

  9. Morphology, structure and optical properties of sol-gel ITO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stoica, T.F.; Teodorescu, V.S.; Blanchin, M.G.; Stoica, T.A.; Gartner, M.; Losurdo, M.; Zaharescu, M

    2003-08-15

    The alkoxidic route and the spinning deposition were used to prepare monolayer sol-gel indium tin oxide (ITO) films. The morphology and crystalline structure were investigated by cross-section transmission electron microscopy (XTEM) and atomic force microscopy (AFM). The ITO sol-gel mono-layer contains three regions of different porosities. The basic crystalline structure is that of the In{sub 2}O{sub 3} lattice. The optical properties have been studied by optical transmission and spectroscopic ellipsometry.

  10. Structure and Dynamics of Thin Polyacrylate Gel Films Supported on a Polymeric Substrate

    Science.gov (United States)

    Mani, Sriramvignesh; Islam, Rafikul; Khare, Rajesh

    Recently, we have used molecular dynamics (MD) simulations to demonstrate the viability of polyacrylate gel membranes for pervaporation based separation processes. In practice, these polymeric membranes are usually in the form of thin films that are supported on another polymeric substrate such as polysulfone or cellulose acetate. The structure and dynamics of the polymer constituting the membrane play an important role in governing the separation efficiency of these membranes. Since chain structure and dynamics in supported polymer thin films deviate significantly from their bulk values, it is necessary to understand the effect of the soft polymeric support on the properties of the polymer constituting the membranes. In this work, the structural and dynamic properties of polyacrylate gels that are supported on polysulfone are studied using molecular simulations. Specifically, three different networks formed by poly butyl acrylate (PBA), 50-50 random copolymer of butyl acrylate and 2-hydroxy ethyl acrylate (P(BA50-HEA50)), and poly 2-hydroxyethyl acrylate (PHEA) are considered. The properties of the supported thin film gel systems are characterized by determining the gel structure, glass transition temperature, and chain dynamics. The effect of the polysulfone support on the system behavior is determined by comparing the properties of the supported thin films systems with those of the bulk gel systems.

  11. Densification and crystallization of zirconia thin films prepared by sol-gel processing

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, R.W.; Voigt, J.A.; Buchheit, C.D.; Boyle, T.J.

    1993-12-31

    We have investigated the effects of precursor nature and heat treatment schedule on the densification and crystallization behavior of sol-gel derived zirconia thin films. Precursor solutions were prepared from n-propanol, zirconium (IV) n-propoxide, and either acetic acid, or 2,4-pentanedione (acac) and water additions. By controlling the ligand type and ligand-to-metal ratio, we were able to prepare films which displayed significant differences in densification behavior. We attribute the dissimilarity in densification to variations in the nature of the as-deposited films, as influenced by ligand type and concentration. While the acac- derived film was a physical gel, (i.e., a physical aggregation of the oligomeric species), the acetic acid-derived film, which exhibited less consolidation, was a chemical gel that could not be redissolved in the parent solvent. Films prepared with large acac/metal ratios and small water additions exhibited minimal crosslinking at 25{degree}C, displayed the greatest consolidation ({approximately}86% shrinkage) and the highest refractive index (n = 2.071) when heat treated. These results indicate the importance that M-O-M bonds (crosslinks) formed at low temperature can have on densification behavior. We also report on the effects of heat-treatment schedules and ramp rates on densification behavior. All of the films of the present study crystallized into the cubic phase, at temperatures ranging from {approximately}400{degree}C to greater than 700{degree}C, depending on the heating rate.

  12. Fabrication of superhydrophobic sol-gel composite films using hydrophobically modified colloidal zinc hydroxide.

    Science.gov (United States)

    Lakshmi, R V; Basu, Bharathibai J

    2009-11-15

    A superhydrophobic sol-gel composite film was fabricated by incorporating hydrophobically modified colloidal zinc hydroxide (CZH) in sol-gel matrix. CZH was prepared by controlled precipitation and modified by treatment with stearic acid. The concentration of stearic acid and stirring time were optimized to obtain modified CZH with very high water contact angle (WCA) of 165 degrees and sliding angle (SA)superhydrophobic surfaces. FTIR spectrum also confirmed the presence of zinc stearate in the composite film. The method is simple and cost-effective and does not involve any expensive chemicals or equipments.

  13. 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.

  14. Li+ ions diffusion into sol-gel V2O5 thin films: electrochromic properties

    Science.gov (United States)

    Benmoussa, M.; Outzourhit, A.; Bennouna, A.; Ihlal, A.

    2009-10-01

    V{2}O{5} thin films were prepared by the sol-gel spin coating process. The Li+ ions insertion effect on optical and electrochromic properties of those films was studied. The diffusion coefficient was calculated using both cyclic voltammograms and chronoamperometric curves. The amount x of Li+ ions in LixV{2}O{5} was also calculated. Finally, the electrochromic performance evolution characteristics such as the reversibility, coloration efficiency, coloration memory stability and response time were studied.

  15. Indirect excitation of Er3+ in sol-gel hybrid films doped with an erbium complex

    Science.gov (United States)

    Park, Oun-Ho; Seo, Se-Young; Bae, Byeong-Soo; Shin, Jung H.

    2003-04-01

    Transparent sol-gel hybrid films doped with erbium tris 8-hydroxyquinoline were prepared using methyltriethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane as precursors. We obtain a strong 1.53-μm Er3+ luminescence with a wide full width at half-maximum and no thermal quenching. Comparison of absorption of the film with the pump wavelength dependence of Er3+ luminescence intensity indicates the presence of an efficient indirect excitation path for Er3+ via organic ligands.

  16. RBS and NRA of cobalt oxide thin films prepared by the sol-gel process

    International Nuclear Information System (INIS)

    Andrade, E.; Huerta, L.; Pineda, J.C.; Zavala, E.P.; Barrera, E.; Rocha, M. F.; Vargas, C.A.

    2001-01-01

    This work presents a study of cobalt oxide thin films produced by the sol-gel process on aluminum and glass substrates. These films have been analyzed using two ion beam analysis (IBA) techniques: a) a standard RBS 4 He 2 MeV and b) nuclear reaction analysis (NRA) using a 1 MeV deuterium beam. The 12 C(d,p 0 ) 13 C nuclear reaction provides information that carbon is incorporated into the film structure, which could be associated to the sinterization film process. Other film measurements such as optical properties, XRD, and SEM were performed in order to complement the IBA analysis. The results show that cobalt oxide film coatings prepared by this technique have good optical properties as solar absorbers and potential uses in solar energy applications

  17. New resin gel for uranium determination by diffusive gradient in thin films technique

    International Nuclear Information System (INIS)

    Gregusova, Michaela; Docekal, Bohumil

    2011-01-01

    A new resin gel based on Spheron-Oxin chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 10 2 mg L -1 . The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1-2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel.

  18. Synthesis and characterization of nanostructured strontium hexaferrite thin films by the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Masoudpanah, S.M., E-mail: masoodpanah@ut.ac.ir [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Seyyed Ebrahimi, S.A. [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, University of Tehran, Tehran (Iran, Islamic Republic of)

    2012-07-15

    Nanostructured single phase strontium hexaferrite, SrFe{sub 12}O{sub 19}, thin films have been synthesized on the (100) silicon substrate using a spin coating sol-gel process. The thin films with various Fe/Sr molar ratios of 8-12 were calcined at different temperatures from 500 to 900 Degree-Sign C. The composition, microstructure and magnetic properties of the SrFe{sub 12}O{sub 19} thin films were characterized using Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetry, X-ray diffraction, electron microscopy and vibrating sample magnetometer. The results showed that the optimum molar ratio for Fe/Sr was 10 at which the lowest calcination temperature to obtain the single phase strontium hexaferrite thin film was 800 Degree-Sign C. The magnetic measurements revealed that the sample with Fe/Sr molar ratio of 10, exhibited higher saturation magnetization (267.5 emu/cm{sup 3}) and coercivity (4290 Oe) in comparison with those synthesized under other Fe/Sr molar ratios. - Highlights: Black-Right-Pointing-Pointer Preparing of strontium hexaferrite thin film by sol-gel spin coating. Black-Right-Pointing-Pointer The films prepared from the solutions with different Fe/Sr=8-12. Black-Right-Pointing-Pointer The film with Fe/Sr=10 has the lowest calcination temperature, 800 Degree-Sign c. Black-Right-Pointing-Pointer The film with Fe/Sr=10 has simultaneously maximum saturation magnetization and coercivity.

  19. Sol-Gel Thin Films for Plasmonic Gas Sensors

    Science.gov (United States)

    Della Gaspera, Enrico; Martucci, Alessandro

    2015-01-01

    Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors. PMID:26184216

  20. Tin dioxide sol-gel derived thin films deposited on porous silicon

    NARCIS (Netherlands)

    Cobianu, C.; Savaniu, Cristian; Buiu, Octavian; Zaharescu, Maria; Parlog, Constanta; van den Berg, Albert; Pecz, Bela; Dascula, Dan

    1996-01-01

    Undoped and Sb-doped SnO2 sol–gel derived thin films have been prepared for the first time from tin (IV) ethoxide precursor and SbCl3 in order to be utilised for gas sensing applications where porous silicon is used as a substrate. Transparent, crack-free and adherent layers were obtained on

  1. Tin dioxide sol-gel derived thin films deposited on porous silicon

    NARCIS (Netherlands)

    Cobianu, C.; Savaniu, Cristian; Buiu, Octavian; Dascalu, Dan; Zaharescu, Maria; Parlog, Constanta; van den Berg, Albert; Pecz, Bela

    1997-01-01

    Undoped and Sb-doped SnO2 sol¿gel derived thin films have been prepared for the first time from tin (IV) ethoxide precursor and SbCl3 in order to be utilised for gas sensing applications where porous silicon is used as a substrate. Transparent, crack-free and adherent layers were obtained on

  2. Thermally induced evolution of sol–gel grown WO3 films on ITO/glass substrates

    NARCIS (Netherlands)

    Caruso, T.; Castriota, M.; Policicchio, A.; Fasanella, A.; Santo, M.P. De; Ciuchi, F.; Desiderio, G.; Rosa, S. La; Rudolf, P.; Agostino, R.G.; Cazzanelli, E.

    2014-01-01

    The electronic, morphological and structural properties of WO3 thin films, synthesized via a sol-gel route and deposited on ITO/glass substrates by spin-coating, were analyzed as a function of annealing temperature (100-700 degrees C range) by Scanning Electron Microscopy, Atomic Force Microscopy,

  3. New resin gel for uranium determination by diffusive gradient in thin films technique

    Czech Academy of Sciences Publication Activity Database

    Gregušová, Michaela; Dočekal, Bohumil

    2011-01-01

    Roč. 684, 1-2 (2011), s. 142-146 ISSN 0003-2670 R&D Projects: GA ČR GAP503/10/2002 Institutional research plan: CEZ:AV0Z40310501 Keywords : diffusive gradient in thin film technique * 8-hydroxyquinoline resin gel * uranium determination Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.555, year: 2011

  4. Synthesis and characterization of polymer-silica hybrid latexes and sol-gel-derived films

    Energy Technology Data Exchange (ETDEWEB)

    Petcu, Cristian; Purcar, Violeta [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Ianchiş, Raluca, E-mail: ralumoc@yahoo.com [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Spătaru, Cătălin-Ilie; Ghiurea, Marius; Nicolae, Cristian Andi [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Stroescu, Hermine [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Splaiul Independentei 202, 060021, Bucharest (Romania); Atanase, Leonard-Ionuţ [University Apollonia, “Acad. Ioan Haulica” Research Institute, Iasi (Romania); Frone, Adriana Nicoleta; Trică, Bogdan; Donescu, Dan [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania)

    2016-12-15

    Highlights: • Si-based polymer is distributed onto the silica surface of sol-gel hybrid films. • FT-IR spectra of sol-gel derived materials confirmed the different chemical structure. • Hydrophobicity increased due to the increasing number of alkyl groups attached to the surface. - Abstract: Sol-gel derived organic-inorganic hybrid systems were obtained by applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), isobutyltriethoxysilane (IBTES), diethoxydimethylsilane (DMDES), and vinyltriethoxysilane (VTES), respectively, into a polymer latex functionalized with vinyltriethoxysilane (VTES). The properties of the latex hybrid materials were analyzed by FTIR, water contact angle, environmental scanning electron microscopy (ESEM), TEM and AFM analysis, respectively. FT-IR spectra confirmed that the chemical structures of the sol-gel derived organic-inorganic materials are changed as function of inorganic precursor and Si−O−Si networks are formed during the co-hydrolysis and copolycondensation reactions. The water contact angle on the sol-gel latex film containing TEOS + VTES increased to 135° ± 2 compared to 65° ± 5 for the blank latex, due VTES incorporation into latex material. TGA curves of hybrid sample modifies against neat polymer, the thermal stability being influenced by the presence of the inorganic partner. ESEM analysis showed that the latex hybrid films prepared with different inorganic precursors were formed and the Si-based polymers were distributed on the surface of the dried sol-gel hybrid films. TEM and AFM photos revealed that the latex emulsion morphology was modified due to the VTES incorporation into system.

  5. Chemical Processing for Sol-Gel Derived Metal Oxide Thin Films using Supercritical Carbon Dioxide Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Asai, Y; Narishige, S; Fujioka, K; Uchida, H; Koda, S, E-mail: uchidah@sophia.ac.jp [Sophia University, Department of Materials and Life Sciences, Tokyo 102-8554 (Japan)

    2011-10-29

    Chemical processing using supercritical carbon dioxide fluid (scCO{sub 2}) was demonstrated for lowering processing temperature of sol-gel-derived metal oxide thin films. The film processing was performed in a hot-wall closed vessel filled with scCO{sub 2} fluid. Precursor films of titanium dioxide (TiO{sub 2}) on soda-glass substrates prepared by sol-gel coating using Ti-alkoxide solution were converted to crystalline TiO{sub 2} (anatase) films successfully by the scCO{sub 2} treatment at a fluid pressure of 15 MPa and a substrate temperature of 300deg. C whereas no crystallization was occurred by conventional heat treatment at 400 deg. C. XPS analysis indicated that the interface reaction related to Si element was suppressed successfully by scCO{sub 2} treatment at 300 deg. C. These results suggest that the sol-gel synthesis using scCO{sub 2} fluid would be a cadidate for low-temperature processing of crystalline oxide films, which is more preferable than conventional techniques based on the heat treatment.

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

    Science.gov (United States)

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

    2014-01-01

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

  7. Low Loss Sol-Gel TiO2 Thin Films for Waveguiding Applications

    Directory of Open Access Journals (Sweden)

    Alexis Fischer

    2013-03-01

    Full Text Available TiO2 thin films were synthesized by sol-gel process: titanium tetraisopropoxide (TTIP was dissolved in isopropanol, and then hydrolyzed by adding a water/isopropanol mixture with a controlled hydrolysis ratio. The as prepared sol was deposited by “dip-coating” on a glass substrate with a controlled withdrawal speed. The obtained films were annealed at 350 and 500 °C (2 h. The morphological properties of the prepared films were analyzed by Scanning Electron Microscopy (SEM and Atomic Force Microscopy (AFM. The optical waveguiding properties of TiO2 films were investigated for both annealing temperature using m-lines spectroscopy. The refractive indices and the film thickness were determined from the measured effective indices. The results show that the synthesized planar waveguides are multimodes and demonstrate low propagation losses of 0.5 and 0.8 dB/cm for annealing temperature 350 and 500 °C, respectively.

  8. Observation and manipulation of magnetic domains in sol gel derived thin films of spinel ferrites

    Science.gov (United States)

    Datar, Ashwini A.; Mathe, Vikas L.

    2017-12-01

    Thin films of spinel ferrites, namely zinc substituted nickel, cobalt ferrite, and manganese substituted cobalt ferrite, were synthesized using sol-gel derived spin-coating techniques. The films were characterized using x-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy techniques for the analysis of structural, morphological and vibrational band transition properties, which confirm the spinel phase formation of the films. The magnetic force microscopy (MFM) technique was used to observe the magnetic domain structure present in the synthesized films. Further, the films were subjected to an external DC magnetic field of 2 kG to orient the magnetic domains and analyzed using an ex situ MFM technique.

  9. Electrochemically deposited sol-gel-derived silicate films as a viable alternative in thin-film design.

    Science.gov (United States)

    Deepa, P N; Kanungo, Mandakini; Claycomb, Greg; Sherwood, Peter M A; Collinson, Maryanne M

    2003-10-15

    Sol-gel-derived silicate films were electrochemically deposited on conducting surfaces from a sol consisting of tetramethoxysilane (TMOS). In this method, a sufficiently negative potential is applied to the electrode surface to reduce oxygen to hydroxyl ions, which serves as the catalyst for the hydrolysis and condensation of TMOS. The electrodeposition process was followed by the electrochemical quartz crystal microbalance and cyclic voltammetry. The electrodeposited films were characterized for their surface morphology, porosity, and film thickness using atomic force microscopy, electrochemical probe techniques, surface area and pore size analysis, and profilometry. The electrodeposited films were found to have a completely different surface structure and to be significantly rougher relative to spin-coated films. This is likely due in part to the separation of the gelation and evaporation stages of film formation. The electrodeposited films were found to be permeable to simple redox molecules, such as ruthenium(III) hexaammine and ferrocene methanol. Film thickness can be easily varied from 15 microm by varying the electrode potential from -600 mV to more than -1000 mV, respectively. The electrodeposition process was further applied for the electroencapsulation of redox molecules and organic dyes within the silicate network. Cyclic voltammograms for the gel-entrapped ferrocene methanol (FcCH2OH) and ruthenium(II) tris(bipyridine) (Ru(bpy)3(2+)) exhibited the characteristic redox behavior of the molecules. The electroencapsulation of organic dyes in their "native" form proved to be more difficult because these species typically contain reducible functionalities that change the structure of the dye.

  10. Preparation and properties of sol-gel thin film containing quinacridone latent pigment by using laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ohishi, T; Ishitsuka, H, E-mail: tooishi@sic.shibaura-it.ac.jp [Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology, Toyosu 3-7-5, Koto-ku, Tokyo, 135-8548 Japan (Japan)

    2011-10-29

    The synthesis of Ph-SiO{sub 2} film containing Qn-BOC latent pigment using the sol-gel method and the formation of thin film using laser irradiation have been investigated. The film is useful for a wavelength selective absorption film for displays and optical disk. Newly developed film formation technique using latent pigment and laser irradiation gives the excellent film having high transparency, excellent absorption characteristics and high durability. And also, this process is low cost process due to high speed film formation.

  11. Characterization of iron oxide thin films prepared by sol-gel processing.

    Science.gov (United States)

    Karakuscu, Aylin; Ozenbas, Macit

    2008-02-01

    Iron oxide thin films were prepared by spin-coating a gel solution of iron(III) nitrate dissolved in 2-methoxyethanol and acetylacetone on glass and quartz substrates. The film thickness was adjusted by changing the spinning rate of the spin coater. Annealing was carried out between 300 degrees C to 600 degrees C to investigate the phases present in the films. Viscosity of the main solution was found as 0.0035 Pa.s by viscosity measurement. TGA/DTA analyses showed that heat treatment should be done between 330 degrees C and 440 degrees C in order to produce maghemite thin films. SEM studies showed that single layer thickness of the films were between 65 and 80 nm. The structural characteristics were evaluated by changing the experimental parameters which are annealing temperature, annealing time and thickness of the films. From the X-ray diffraction analysis, maghemite formation was observed with decreasing annealing temperature, annealing time and film thickness. TEM results verified the presence of the maghemite phase by electron diffraction and selected area electron diffraction (SAED) methods. According to UV-Vis results transmittance of the films decreases with increasing annealing temperature.

  12. Wafer scale lead zirconate titanate film preparation by sol-gel method using stress balance layer

    International Nuclear Information System (INIS)

    Lu Jian; Kobayashi, Takeshi; Yi Zhang; Maeda, Ryutaro; Mihara, Takashi

    2006-01-01

    In this paper, platinum/titanium (Pt/Ti) film was introduced as a residual stress balance layer into wafer scale thick lead zirconate titanate (PZT) film fabrication by sol-gel method. The stress developing in PZT film's bottom electrode as well as in PZT film itself during deposition were analyzed; the wafer curvatures, PZT crystallizations and PZT electric properties before and after using Pt/Ti stress balance layer were studied and compared. It was found that this layer is effective to balance the residual stress in PZT film's bottom electrode induced by thermal expansion coefficient mismatch and Ti diffusion, thus can notably reduce the curvature of 4-in. wafer from - 40.5 μm to - 12.9 μm after PZT film deposition. This stress balance layer was also found effective to avoid the PZT film cracking even when annealed by rapid thermal annealing with heating-rate up to 10.5 deg. C/s. According to X-ray diffraction analysis and electric properties characterization, crack-free uniform 1-μm-thick PZT film with preferred pervoskite (001) orientation, excellent dielectric constant, as high as 1310, and excellent remanent polarization, as high as 39.8 μC/cm 2 , can be obtained on 4-in. wafer

  13. Properties of Zn O/Cr thin films prepared by Sol-Gel

    International Nuclear Information System (INIS)

    Tirado G, S.; Olvera A, R.

    2014-08-01

    Zn O films and those superficially modified with chromium were deposited on substrates of soda-lime glass, using the Sol-Gel process and the repeated immersion method. Starting from dehydrated zinc acetate was prepared a solution to 0.6 M to ambient temperature in 2-methoxyethanol and monoethanolamine (Mea) stirring magnetically. The Sol was prepared with an aging to seven days and was used to grow a films group with thickness to eight immersions. These same films were superficially modified with several depositions of a chromium nitrate Sol dissolved in ethanol to low concentration. The Zn O films were structurally characterized by X-ray diffraction, its chemical composition by energy dispersive X-ray spectroscopy and its morphology by scanning electron microscopy and atomic force microscopy, as well as their optical properties by UV-vis. Of the obtained results are proposed possible applications. (author)

  14. Sol-gel derived zinc oxide films alloyed with cobalt and aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mamta [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021 (India); Mehra, R.M., E-mail: rammehra2003@yahoo.co [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021 (India)

    2010-05-03

    ZnO films codoped with 5 at.% Co and 1 at.% Al were prepared by sol-gel technique on corning glass and silicon substrates with precursor sols of different pH values. The pH was varied from 5.4 to 11 by adding varying amounts of monoethanolamine to the sol. Since pH plays an important role in controlling the properties of films, we discuss in detail the effect of pH value on the structural, morphological and optical properties of the grown films. X-ray diffraction and atomic force microscopy images reveal that the size of crystallites increases with pH of the sol. The variation of pH in the reaction system influences the density of homogeneous nucleation and the crystal growth along the c-axis. High quality Co and Al codoped ZnO films annealed at 600 {sup o}C have been obtained using a sol with pH = 9. These sol-gel derived films find their suitability to be used as dilute magnetic semiconductors.

  15. Sol-gel derived zinc oxide films alloyed with cobalt and aluminium

    International Nuclear Information System (INIS)

    Sharma, Mamta; Mehra, R.M.

    2010-01-01

    ZnO films codoped with 5 at.% Co and 1 at.% Al were prepared by sol-gel technique on corning glass and silicon substrates with precursor sols of different pH values. The pH was varied from 5.4 to 11 by adding varying amounts of monoethanolamine to the sol. Since pH plays an important role in controlling the properties of films, we discuss in detail the effect of pH value on the structural, morphological and optical properties of the grown films. X-ray diffraction and atomic force microscopy images reveal that the size of crystallites increases with pH of the sol. The variation of pH in the reaction system influences the density of homogeneous nucleation and the crystal growth along the c-axis. High quality Co and Al codoped ZnO films annealed at 600 o C have been obtained using a sol with pH = 9. These sol-gel derived films find their suitability to be used as dilute magnetic semiconductors.

  16. Scanning electrochemical microscopy study of laccase within a sol-gel processed silicate film.

    Science.gov (United States)

    Nogala, Wojciech; Burchardt, Malte; Opallo, Marcin; Rogalski, Jerzy; Wittstock, Gunther

    2008-04-01

    The enzyme p-diphenol:dioxygen oxidoreductase (laccase, EC 1.10.3.2) was isolated from Cerrena unicolor fungus and embedded in a sol-gel film obtained by acidic condensation of TMOS. The gel was cast to thin films on glass. The laccase-containing silicate films were inspected by confocal laser scanning microscopy (CLSM), scanning force microscopy (SFM) and scanning electrochemical microscopy (SECM). CLSM images in the reflection mode showed aggregates within the silicate films. SECM images in the substrate-generation/tip-collection mode using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as electron donor for laccase showed that the position of aggregates coincides with increased enzymatic activity within the silicate film. The flux from individual aggregates was detected. SECM images in the redox competition mode confirmed the assignment and could exclude that topographic features observed by CLSM and SFM could be the reason for the image contrast. SFM images showed that the aggregates partially dissolve during prolonged exposure to aqueous buffer. The experimental setup allowed following one individual aggregate over time with all three microscopic techniques which enabled the collection of complementing information on morphology and catalytic activity as well as their development over time.

  17. Comparative study of ZnO thin films prepared by different sol-gel route

    Directory of Open Access Journals (Sweden)

    F Esmaieli Ghodsi

    2012-03-01

    Full Text Available   Retraction Notice    The paper "Comparative study of ZnO thin films prepared by different sol-gel route" by H. Absalan and F. E. Ghodsi, which appeared in Iranian Journal of Physics Research, Vol. 11, No. 4, 423-428 (in Farsi is translation of the paper "Comparative Study of ZnO Thin Films Prepared by Different Sol-Gel Route" by F. E. Ghodsi and H. Absalan, which appeared in ACTA PHYSICA POLONICA A, Vol 118 (2010 (in English and for this reason is retracted from this journal.The corresponding author  (and also the first author is the only responsible person for this action.   

  18. Amperometric biosensor for hydrogen peroxide based on hemoglobin entrapped in titania sol-gel film

    International Nuclear Information System (INIS)

    Yu Jiuhong; Ju Huangxian

    2003-01-01

    Hemoglobin (Hb) was entrapped in a titania sol-gel matrix and used as a mimetic peroxidase to construct a novel amperometric biosensor for hydrogen peroxide. The Hb entrapped titania sol-gel film was obtained with a vapor deposition method, which simplified the traditional sol-gel process for protein immobilization. The morphologies of both titania sol-gel and the Hb films were characterized using scanning electron microscopy (SEM) and proved to be chemically clean, porous, homogeneous. This matrix provided a biocompatible microenvironment for retaining the native structure and activity of the entrapped Hb and a very low mass transport barrier to the substrates. H 2 O 2 could be reduced by the catalysis of the entrapped hemoglobin at -300 mV without any mediator. The reagentless H 2 O 2 sensor exhibited a fast response (less than 5 s) and sensitivity as high as 1.29 mA mM -1 cm -2 . The linear range for H 2 O 2 determination was from 5.0x10 -7 to 5.4x10 -5 M with a detection limit of 1.2x10 -7 M. The apparent Michaelis-Menten constant of the encapsulated hemoglobin was calculated to be 0.18±0.02 mM. The stability of the biosensor was also evaluated

  19. Zinc oxide films impurified with Ti and prepared by the Sol-gel method

    International Nuclear Information System (INIS)

    Tirado G, S.; Cazares R, J.M.; Maldonado, A.

    2006-01-01

    Titanium-doped zinc oxide thin films have been prepared on silicon substrate using the Sol-Gel technique. The structural, morphology, electrical and optical properties of such thin films were studied as a function of titanium concentration (0.5, 1 and 1.5 %) and the thin films thickness. Zinc acetate dihydrate and titanium (VI)-oxy acetylacetonate were used as precursor materials, using 2-methoxyethanol and monoethanolamine as via. The X-ray diffraction spectra show polycrystalline films in all the cases. It can see for all the thin films a preferential growth along the (002) planes where the titanium concentration and also the thin films thickness play an important rule. No structural changes are observed at all. The surface morphology studied shows as the grain size decreases when thin thickness is increases. For titanium concentration of 0.5, 1 and 1.5 % values the grains size increase also. The thin films thickness for titanium concentration of 1.5 % was 500 nm (4v), 400 nm (3v), 180 nm (2v) and 130 nm (1v), values obtained from cross-section micrographs. Highly resistive samples are obtained for substrate soda-lime even showing high transmittance. Better physical properties are required for gas sensors or semitransparent electrodes and other possible applications. (Author)

  20. Sol-Gel TiO2 thin films sensitized with the mulberry pigment cyanidin

    Directory of Open Access Journals (Sweden)

    Emerson Henrique de Faria

    2007-12-01

    Full Text Available TiO2 films have various applications, among them solar cells and photodegradation of pollutants. In this study, we investigated TiO2 films functionalized with the organic dye cyanidin extracted from black mulberry (Morus nigra. The TiO2 was functionalized by the sol-gel method and the film was deposited on glass substrates by dip-coating. Our aim was to investigate the interaction between the semiconductor and the dye, as well as the influence of the velocity and number of deposits on the characteristics of the film. Using ultraviolet-visible spectroscopy, we observed a shift from the maximum absorption band at 545 nm for the dye’s ethanol solution to 595 nm for the film, indicating interaction of the cyanidin with the TiO2. The absorption spectra in the infrared region of the functionalized TiO2 particles showed bands characteristic of the oxide and indicated their interaction with the dye. Using profilometry and m-line techniques, we found that the films presented thicknesses in the order of 100 nm. A SEM analysis confirmed the high density of the films.

  1. Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique

    Directory of Open Access Journals (Sweden)

    M.I. Khan

    Full Text Available In this work, zinc oxide (ZnO multilayer thin films are deposited on glass substrate using sol-gel spin coating technique and the effect of these multilayer films on optical, electrical and structural properties are investigated. It is observed that these multilayer films have great impact on the properties of ZnO. X-ray Diffraction (XRD confirms that ZnO has hexagonal wurtzite structure. Scanning Electron Microscopy (SEM showed the crack-free films which have uniformly distributed grains structures. Both micro and nano particles of ZnO are present on thin films. Four point probe measured the electrical properties showed the decreasing trend between the average resistivity and the number of layers. The optical absorption spectra measured using UV–Vis. showed the average transmittance in the visible region of all films is 80% which is good for solar spectra. The performance of the multilayer as transparent conducting material is better than the single layer of ZnO. This work provides a low cost, environment friendly and well abandoned material for solar cells applications. Keywords: Multilayer films, Semiconductor, ZnO, XRD, SEM, Optoelectronic properties

  2. Sol-gel preparation of ion-conducting ceramics for use in thin films

    International Nuclear Information System (INIS)

    Steinhauser, M.I.

    1992-12-01

    A metal alkoxide sol-gel solution suitable for depositing a thin film of La 0.6 Sr 0.4 CoO 3 on a porous substrate has been developed; such films should be useful in fuel cell electrode and oxygen separation membrane manufacture. Crack-free films have been deposited on both dense and porous substrates by dip-coating and spin-coating techniques followed by a heat treatment in air. Fourier transform infrared spectroscopy was used to determine the chemical structure of metal alkoxide solution system. X-ray diffraction was used to determine crystalline phases formed at various temperatures, while scanning electron microscopy was used to determine physical characteristics of the films. Surface coatings have been successfully applied to porous substrates through the control of the substrate pore size, deposition parameters, and firing parameters. Conditions have been defined for which films can be deposited, and for which the physical and chemical characteristics of the film can be improved. A theoretical discussion of the chemical reactions taking place before and after hydrolysis in the mixed alkoxide solutions is presented, and the conditions necessary for successful synthesis are defined. Applicability of these films as ionic and electronic conductors is discussed

  3. Weathering characteristics and moisture uptake properties of wood coated with water-borne sol-gel thin films

    Science.gov (United States)

    M. A. Tshabalala; C. Starr; N. R. Sutherland

    2010-01-01

    In this study, wood specimens were coated with water-borne silsesquioxane oligomers by an in situ sol-gel deposition process. The effect of these water-borne sol-gel thin films on weathering characteristics and moisture-uptake properties of the wood specimens were investigated. The weathering characteristics were investigated by exposure of the specimens to artificial...

  4. Ultraviolet-B radiation induced crosslinking improves physical properties of cold- and warm-water fish gelatin gels and films

    Science.gov (United States)

    Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm2. Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rhe...

  5. Ultraviolet Stimulated Emission from Sol-Gel Spin Coated ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Ahmed S. Razeen

    2017-01-01

    Full Text Available Low cost ultraviolet stimulated emission has been generated using optical excitation of ZnO thin films deposited by sol-gel spin coating on n+ As-doped 100 Si-substrate. The number of deposited layers and the heat treatment have been investigated to obtain a film that can generate stimulated emission under optical excitation. The optimum condition for preparation of the film has been presented. X-ray diffraction and scanning electron microscope have been used for structural and morphological investigations. Input-output intensity dependence and spectral width, peak emission wavelength, and the quantum efficiency versus the pump intensity have been presented. A quantum efficiency of about 24.2% has been reported, a power exponent higher than 8 has been obtained in input-output intensity dependence, and a threshold of about 23 Mw/cm2 has been evaluated for the samples. The mechanism by which stimulated emission occurs has been discussed. The results show that sol-gel spin coating is a promising method for generating ultraviolet stimulated emission from ZnO thin films.

  6. Synthesis of zinc oxide thin films prepared by sol-gel for specific bioactivity

    Science.gov (United States)

    Adam, Tijjani; Basri, B.; Dhahi, Th. S.; Mohammed, Mohammed; Hashim, U.; Noriman, N. Z.; Dahham, Omar S.

    2017-09-01

    Zinc oxide (ZnO) thin films this device to used for many application like chemical sensor, biosensor, solar energy, etc but my project to use for bioactivity(biosensor). Zinc oxide (ZnO) thin films have been grown using sol-gel technique. Characterization was done using Scanning Electron Microscope (SEM), Energy Dispersive X-ray(EDX) and Electrical Measurement(I-V). ZnO thin film was successfully synthesized using low cost sol-gel spin coating method. The coupling of DNA probe to ZnO thin film supports modified with carboxylic acid (COOH) is certainly the best practical method to make DNA immobilization and it does not require any coupling agent which could be a source of variability during the spotting with an automatic device. So, selected this coupling procedure for further experiments. The sensor was tested with initial trial with low concentrated DNA and able to detect detection of the disease effectively. Silicon-on-insulator (SOI) wafer device with ZnO can detect at different concentration in order to valid the device capabilities for detecting development. The lowest concentration 1 µM HPV DNA probe can detect is 0.1 nM HPV target DNA.

  7. Mesoporous silica thin films prepared by argon plasma treatment of sol-gel-derived precursor

    International Nuclear Information System (INIS)

    Zhang Jian; Palaniappan, Alagappan; Su Xiaodi; Tay, Francis E.H.

    2005-01-01

    Argon plasma is used to generate the mesoporous silica thin films from sol-gel-derived precursor. Poly(ethylene glycol) (PEG, MW = 400) is employed as the template, i.e., the pore-directing agent as well as the binder. The influence of the plasma parameters (plasma power and processing time) on the mesoscopic properties of silica films are investigated by scanning electron microscopy (SEM), FT-IR, low-angle X-ray scattering (SAXS), and nitrogen adsorption isotherm. It is concluded that the plasma treatment is a promising way to remove organic templates and generate mesoporous thin films. Compared to the conventional thermal calcination methods, the plasma treatment provides a promising low-temperature, low-cost and time-saving preparation process

  8. SiO2 sol-gel films after ammonia and heat two-step treatments

    International Nuclear Information System (INIS)

    Zhang Chunlai; Wang Biyi; Tian Dongbin; Yin Wei; Jiang Xiaodong; Yuan Xiaodong; Yan Lianghong; Zhang Hongliang; Zhao Songnan; Lv Haibing

    2008-01-01

    SiO 2 thin films were deposited using tetraethoxylsilane as precursor, ammonia as catalyst on K9 glass by sol-gel method. These films were post-treated by ammonia and heat. The properties of the coatings were characterized by ellipsometer, UV-vis spectrophotometry, FTIR-spectroscopy, scanning probe microscope and contact angle measurement apparatus. The resuits indicate that the thickness of the films with ammonia and heat treatment tend to decrease. Both the refractive index and water contact angle increase after ammonia treatment. However, they both decrease after heat treatment. The former increases by 0.236 for the first step, then decreases by 0.202 for the second. The latter increases to 58.92 degree, then decreases to 38.07 degree. The transmittance of the coatings turn to be better and continuously shift to short wave by UV-vis spectrophotometry. The surface becomes smoother by AFM after the two-step treatment. (authors)

  9. Fabrication and Crystal Structure of Sol-Gel Deposited BST Thin Films with Compositional Gradient

    Directory of Open Access Journals (Sweden)

    Czekaj D.

    2017-06-01

    Full Text Available In the present research technology of compositionally graded barium strontium titanate Ba1-xSrxTiO3 thin films deposited on stainless steel substrates by sol-gel spin coating followed with thermal annealing at T = 650°C is reported. Results of thermal behavior of the sol-gel derived powders with compositions used for fabrication of graded structure (i.e. with Sr mole fraction x = 0.5, 0.4 and 0.3 are described. X-ray diffraction studies of the phase composition and crystal structure of such complex thin film configuration are given. It was found that gel powders exhibited a large total weight loss of about Δm ≈ 44-47%. Three stages of weight loss took place at temperature ranges: below T ≈ 300°C, at ΔT ≈ 300-500°C and between T = 600°C and T = 800°C. Phase analysis has shown that the dominating phase is Ba0.67Sr0.33TiO3 compound while the second phase is Ba0.7Sr0.3TiO3 or Ba0.5Sr0.5TiO3 for “up-graded” and “down-graded” structure, respectively.

  10. Enhanced Design of a Soft Thin-Film Vibrotactile Actuator Based on PVC Gel

    Directory of Open Access Journals (Sweden)

    Won-Hyeong Park

    2017-09-01

    Full Text Available We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to stimulate human skin in a wide frequency range. To achieve this, we investigate the working principle of the PVC gel and suggest a new structure in which most of electric energy contributes to the deformation of the PVC gel. Due to this structure, the vibrational amplitude of the proposed PVC gel actuator could considerably increase (0.816 g (g = 9.8 m/s2 at resonant frequency. The vibrotactile amplitude is proportional to the amount of input voltage. It increased from 0.05 g up to 0.416 g with increasing applied voltages from 200 V to 1 kV at 1 Hz. The experimental results show that the proposed actuator can create a variety of haptic sensations.

  11. Thin-film silica sol-gels doped with ion responsive fluorescent lipid bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, D.Y.; Shea, L.E.; Sinclair, M.B.

    1999-01-12

    A metal ion sensitive, fluorescent lipid-b i layer material (5oA PSIDA/DSPC) was successfully immobilized in a silica matrix using a tetramethoxysilane (TMOS) sol-gel procedure. The sol-gel immobilization method was quantitative in the entrapment of seif-assembled Iipid-bilayers and yielded thin films for facile configuration to optical fiber piatforms. The silica matrix was compatible with the solvent sensitive lipid bilayers and provided physical stabilization as well as biological protection. Immobilization in the silica sol-gel produced an added benefit of improving the bilayer's metal ion sensitivity by up to two orders of magnitude. This enhanced performance was attributed to a preconcentrator effect from the anionic surface of the silica matrix. Thin gels (193 micron thickness) were coupled to a bifurcated fiber optic bundle to produce a metal ion sensor probe. Response times of 10 - 15 minutes to 0.1 M CUCIZ were realized with complete regeneration of the sensor using an ethylenediarninetetraacetic acid (EDTA) solution.

  12. Influence of doping on the properties of vanadium oxide gel films

    Energy Technology Data Exchange (ETDEWEB)

    Pergament, A L; Velichko, A A; Berezina, O Ya; Kazakova, E L; Kuldin, N A; Artyukhin, D V [Physics and Technology Department, Petrozavodsk State University, Petrozavodsk 185910 (Russian Federation)], E-mail: aperg@psu.karelia.ru

    2008-10-22

    The effect of doping with H and W on the properties of V{sub 2}O{sub 5} and VO{sub 2} derived from V{sub 2}O{sub 5} gel has been studied. It is shown that the treatment of V{sub 2}O{sub 5} in low-temperature RF hydrogen plasma for 1-10 min leads to either hydration of vanadium pentoxide or its reduction (depending on the treatment conditions) to lower vanadium oxides. For some samples, which are subject to plasma treatment in the discharge active zone, a non-ordinary temperature dependence of resistance, with a maximum at T{approx}100 K, is observed. For W-doped VO{sub 2} films, it is shown that substitution of V{sup 4+} with W{sup 6+} results in a decrease of the temperature of the metal-insulator transition. Also, it has been shown that the doping of initial films with {approx}3 at.% of W reduces the statistical scatter in the threshold parameters of the switching devices with S-shaped I-V characteristics on the basis of V{sub 2}O{sub 5} gel films. (fast track communication)

  13. Silica doped with lanthanum sol-gel thin films for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Abuin, M. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Serrano, A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); Llopis, J. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Garcia, M.A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); IMDEA Nanoscience, Fco. Tomas y Valiente 7, 28049 Madrid (Spain); Carmona, N., E-mail: n.carmona@fis.ucm.es [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain)

    2012-06-01

    We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol-gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: Black-Right-Pointing-Pointer Silica sol-gel films doped with lanthanum ions were synthesized. Black-Right-Pointing-Pointer Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. Black-Right-Pointing-Pointer La-acetate is an affordable chemical reactive preferred for the industry. Black-Right-Pointing-Pointer Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. Black-Right-Pointing-Pointer An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

  14. Preparation of nickel oxide thin films at different annealing temperature by sol-gel spin coating method

    International Nuclear Information System (INIS)

    Abdullah, M. A. R.; Mamat, M. H.; Ismail, A. S.; Malek, M. F.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-01-01

    Preparation of NiO thin films at different annealing temperature by sol-gel method was conducted to synthesize the quality of the surface thin films. The effects of annealing temperature on the surface topology were systematically investigated. Our studies confirmed that the surface roughness of the thin films was increased whenever annealing temperature was increase. NiO thin films morphology structure analysis was confirmed by field emission scanning electron microscope. Surface roughness of the thin films was investigated by atomic force microscopy.

  15. Reversible wettability of nanostructured ZnO thin films by sol-gel method

    Science.gov (United States)

    Lü, Jianguo; Huang, Kai; Chen, Xuemei; Zhu, Jianbo; Meng, Fanming; Song, Xueping; Sun, Zhaoqi

    2010-05-01

    Nanostructured ZnO thin films were deposited on Si(1 1 1) and quartz substrate by sol-gel method. The thin films were annealed at 673 K, 873 K, and 1073 K for 60 min. Microstructure, surface topography, and water contact angle of the thin films have been measured by X-ray diffractometer, atomic force microscopy, and water contact angle apparatus. XRD results showed that the ZnO thin films are polycrystalline with hexagonal wurtzite structure. AFM studies revealed that rms roughness changes from 2.3 nm to 7.4 nm and the grain size grow up continuously with increasing annealing temperature. Wettability results indicated that hydrophobicity of the un-irradiated ZnO thin films enhances with annealing temperature increase. The hydrophobic ZnO surfaces could be reversibly switched to hydrophilic by alternation of UV illumination and dark storage (thermal treatment). By studying the magnitude and the contact angle reduction rate of the light-induced process, the contribution of surface roughness is discussed.

  16. AZO Thin Films by Sol-Gel Process for Integrated Optics

    Directory of Open Access Journals (Sweden)

    Azzedine Boudrioua

    2013-07-01

    Full Text Available Undoped and aluminum-doped zinc oxide (AZO thin films are prepared by the sol-gel process. Zinc acetate dihydrate, ethanol, and monoethanolamine are used as precursor, solvent, and stabilizer, respectively. In the case of AZO, aluminum nitrate nonahydrate is added to the precursor solution with an atomic percentage equal to 1 and 2 at.% Al. The multi thin layers are deposited by spin-coating onto glass substrates, and are transformed into ZnO upon annealing at 550 °C. Films display a strong preferential orientation, with high values for the Texture Coefficients (TC of the (002 direction (TC(002 ≈ 3. The structural, morphological, and optical properties of the thin films as a function of aluminum content have been investigated using X-Ray Diffraction (XRD, Atomic Force Microscopy (AFM, and Scanning Electronic Microscopy (SEM. Waveguiding properties of the thin films have been also studied using m-lines spectroscopy. The results indicate that the films are monomodes at 632.8 nm with optical propagation optical losses estimated around 1.6 decibel per cm (dB/cm.

  17. Spectroellipsometric study of the sol-gel nanocrystalline ITO multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Stoica, T.F.; Gartner, M.; Losurdo, M.; Teodorescu, V.; Blanchin, M.; Stoica, T.; Zaharescu, M

    2004-05-01

    Tin-doped indium oxide (ITO) thin films have been deposited by sol-gel process using 'sols' of indium and tin isopropoxides. The thickness of one deposited ITO layer is approximately 50 nm. The desired thickness was obtained by 1-5 successive depositions. The XTEM cross-sectional view of an ITO sample with five depositions showed a clear delimitation of the layers with an alternating structure dense/porous ITO layers. The void fraction in porous regions varies between 20 and 25%. Cubic bixbyite In{sub 2}O{sub 3} nanocrystals with size of 10-20 nm and no phases separation of tin oxide were observed. The optical properties of the films have been investigated by optical transmission and spectroscopic ellipsometry. Reliable optical constants and porosity are obtained only with the model of internal structure based on XTEM results.

  18. Sol-gel synthesis and optical properties of titanium dioxide thin film

    Science.gov (United States)

    Ullah, Irfan; Khattak, Shaukat Ali; Ahmad, Tanveer; Saman; Ludhi, Nayab Ali

    2018-03-01

    The titanium dioxide (TiO2) is synthesized by sol-gel method using titanium-tetra-iso-propoxide (TTIP) as a starting material, and deposited on the pre-cleaned glass substrate using spin coating technique at optimized parameters. Energy dispersive X-ray (EDX) spectroscopy confirms successful TiO2 growth. The optical properties concerning the transmission and absorption spectra show 85% transparency and 3.28 eV wide optical band gap for indirect transition, calculated from absorbance. The exponential behavior of absorption edge is observed and attributed to the localized states electronic transitions, curtailed in the indirect band gap of the thin film. The film reveals decreasing refractive index with increasing wavelength. The photoluminescence (PL) study ascertains that luminescent properties are due to the surface defects.

  19. Optical and structural properties of ZnO/ZnMgO composite thin films prepared by sol–gel technique

    International Nuclear Information System (INIS)

    Xu, Linhua; Su, Jing; Chen, Yulin; Zheng, Gaige; Pei, Shixin; Sun, Tingting; Wang, Junfeng; Lai, Min

    2013-01-01

    Highlights: ► ZnMgO thin film and ZnO/ZnMgO composite thin film have been prepared by sol–gel method. ► The intensity of ultraviolet emission of ZnMgO thin film is enhanced two times compared with that of pure ZnO thin film. ► Compared with ZnMgO thin film, ZnO/ZnMgO composite thin film shows better crystallization and optical properties. ► ZnO/ZnMgO composite thin films prepared by sol–gel method have potential applications in many optoelectronic devices. - Abstract: In this study, pure ZnO thin film, Mg-doped ZnO (ZnMgO) thin film, ZnO/ZnMgO and ZnMgO/ZnO composite thin films were prepared by sol–gel technique. The structural and optical properties of the samples were analyzed by X-ray diffraction, scanning electron microscopy, UV–visible spectrophotometer, ellipsometer and photoluminescence spectra, respectively. The results showed that the incorporation of Mg increased the strain, broadened the optical bandgap, and improved the intensity of ultraviolet emission of ZnO thin film. The full width at half maximum (FWHM) of the ultraviolet emission peak was also increased due to Mg-doping at the same time. Compared with pure ZnO and ZnMgO thin films, the ZnO/ZnMgO thin film showed better crystalline quality and ultraviolet emission performance, smaller strains and higher transmittance in the visible range.

  20. Mn{sup 2+} ions distribution in doped sol–gel deposited ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Stefan, Mariana, E-mail: mstefan@infim.ro [National Institute of Materials Physics, P.O. Box MG-7, 077125 Magurele (Romania); Ghica, Daniela; Nistor, Sergiu V.; Maraloiu, Adrian V. [National Institute of Materials Physics, P.O. Box MG-7, 077125 Magurele (Romania); Plugaru, Rodica [National Institute for R & D in Microtechnologies (IMT), Erou Iancu Nicolae Str. 126A, 077190 Bucharest (Romania)

    2017-02-28

    Highlights: • Several Mn{sup 2+} centers observed by EPR in sol–gel ZnO films. • Mn{sup 2+} ions localized at Zn{sup 2+} sites in ZnO grains and disordered ZnO phase. • Sixfold coordinated Mn{sup 2+} ions localized in inter-grain region. • Aggregated Mn in insular-like regions between ZnO grains in the ZnO:5%Mn film. • Aggregated Mn phase presence and distribution observed by EPR and EDX-STEM. - Abstract: The localization and distribution of the Mn{sup 2+} ions in two sol–gel deposited ZnO films doped with different manganese concentrations were investigated by electron paramagnetic resonance spectroscopy and analytical transmission electron microscopy. In the lightly doped sample the Mn{sup 2+} ions are mainly localized substitutionally at isolated tetrahedrally coordinated Zn{sup 2+} sites in both crystalline ZnO nanograins (34%) and surrounding disordered ZnO (52%). In the highly doped ZnO film, a much smaller proportion of manganese substitutes Zn{sup 2+} in the crystalline and disordered ZnO (10%). The main amount (85%) of manganese aggregates in a secondary phase as an insular-like distribution between the ZnO nanograins. The remaining Mn{sup 2+} ions (14% and 5% at low and high doping levels, respectively) are localized at isolated, six-fold coordinated sites, very likely in the disordered intergrain region. Annealing at 600 °C induced changes in the Mn{sup 2+} ions distribution, reflecting the increase of the ZnO crystallization degree, better observed in the lightly doped sample.

  1. Dual-analyte spectroscopic sensing in sol-gel derived polyelectrolyte-silica composite thin films.

    Science.gov (United States)

    Shi, Y; Seliskar, C J; Heineman, W R

    1998-12-01

    Ferrozine (3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p'-disulfonic acid, monosodium salt hydrate), an iron indicator, and HTPS (8-hydroxyl-1,3,6-pyrenetrisulfonic acid, trisodium salt), a pH indicator, were immobilized in sol-gel derived PDMDAAC-SiO(2) (where PDMDAAC stands for poly(dimethyldiallylammonium chloride), composite thin films via ion-exchange. The two indicators were immobilized in two adjacent sections of the same PDMDAAC-SiO(2) film which was supported on a glass optical substrate. The spectroscopic response of the film to both Fe(2+) and H(+) in solutions was investigated by attenuated total reflection (ATR) spectrometry at two well-separated wavelengths, 562 nm for Fe(2+) and 460 nm for H(+). The Ferrozine/HPTS immobilized PDMDAAC-SiO(2) films had the following characteristics: linear range, 2.5x10(-6)-5.0x10(-5) M for Fe(2+), pH 4.1-6.8 for H(+); sensitivity, 2.2x10(4) DeltaA/M for Fe(2+), 0.583 DeltaA/pH for H(+).

  2. Anomalous behavior in ZnMgO thin films deposited by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Amanpal, E-mail: m.gooley@elsevier.com [Department of Electronic Science, Kurukshetra University, Kurukshetra-136119 (India); Hybrid Microcircuit Group, Central Electronics Engineering Research Institute (CEERI)/Council of Scientific and Industrial Research (CSIR), Pilani-333031 (India); Kumar, Dinesh [Department of Electronic Science, Kurukshetra University, Kurukshetra-136119 (India); Khanna, P.K. [Hybrid Microcircuit Group, Central Electronics Engineering Research Institute (CEERI)/Council of Scientific and Industrial Research (CSIR), Pilani-333031 (India); Kumar, Anuj; Kumar, Mukesh [Department of Electronic Science, Kurukshetra University, Kurukshetra-136119 (India); Kumar, Mohit [Research Group Life Science Automation-Technologies, Center for Life Science Automation, Rostock-18119 (Germany)

    2011-06-30

    The magnesium doped zinc oxide is a promising optical material to enhance the luminescence for possible application in solid state lighting. Magnesium doped zinc oxide thin films (Zn{sub 0.85}Mg{sub 0.15}O) were deposited by sol-gel route on p-type silicon and annealed at different temperatures in oxygen environment for an hour. The doping of magnesium in zinc oxide was confirmed by X-Ray diffraction and the samples were found to have wurtzite crystal structure with (002) preferred orientation. The films were characterized by Hall-effect, atomic force microscopy, UV-VIS spectroscopy, photoluminescence (PL) and work function measurements. The different studies exhibited an anomalous behavior for the film annealed at 900 deg. C. The Hall effect, work function measurements and UV-VIS spectroscopy indicated that the resistivity, work function and optical band gap increased as a function of annealing temperature (from 300 deg. C to 700 deg. C) however these parameters were found to decrease for the films annealed above 700 deg. C. The particle size increased with the annealing but for the samples annealed at 900 deg. C, the shape of the grains changed and became elongated like fibers as observed by the atomic force microscopy. The PL measurements displayed the existence of oxygen vacancies defects for the samples annealed at and above 600 deg. C. The possible mechanism for this anomaly has been discussed in this work.

  3. Properties of Zn O/Cr thin films prepared by Sol-Gel; Propiedades de peliculas delgadas ZnO/Cr preparadas por Sol-Gel

    Energy Technology Data Exchange (ETDEWEB)

    Tirado G, S.; Olvera A, R., E-mail: tirado@esfm.ipn.mx [IPN, Escuela Superior de Fisica y Matematicas, Edificio 9, Unidad Profesional A. L. M., San Pedro Zacatenco, 07788 Mexico D. F. (Mexico)

    2014-08-15

    Zn O films and those superficially modified with chromium were deposited on substrates of soda-lime glass, using the Sol-Gel process and the repeated immersion method. Starting from dehydrated zinc acetate was prepared a solution to 0.6 M to ambient temperature in 2-methoxyethanol and monoethanolamine (Mea) stirring magnetically. The Sol was prepared with an aging to seven days and was used to grow a films group with thickness to eight immersions. These same films were superficially modified with several depositions of a chromium nitrate Sol dissolved in ethanol to low concentration. The Zn O films were structurally characterized by X-ray diffraction, its chemical composition by energy dispersive X-ray spectroscopy and its morphology by scanning electron microscopy and atomic force microscopy, as well as their optical properties by UV-vis. Of the obtained results are proposed possible applications. (author)

  4. Sol-gel TiO2 films as NO2 gas sensors

    International Nuclear Information System (INIS)

    Georgieva, V; Gadjanova, V; Grechnikov, A; Donkov, N; Sendova-Vassileva, M; Kirilov, R; Stefanov, P

    2014-01-01

    TiO 2 films were prepared by a sol-gel technique with commercial TiO 2 powder as a source material (P25 Degussa AG). After a special treatment, printing paste was prepared. The TiO 2 layers were formed by means of drop-coating on Si-control wafers and on the Au-electrodes of quartz resonators. The surface morphology of the films was examined by scanning electron microscopy (SEM). Their structure was studied by Raman spectroscopy and the surface composition was determined by X-ray photoelectron spectroscopy (XPS). The layers had a grain-like surface morphology and consisted mainly of anatase TiO 2 phase. The sensitivity of the TiO 2 films to NO 2 was assessed by the quartz crystal microbalance (QCM) technique. To this end, the films were deposited on both sides of a 16-MHz QCM. The sensing characteristic of the TiO 2 -QCM structure was investigated by measuring the resonant frequency shift (ΔF) of the QCM due to the mass loading caused by NO 2 adsorption. The Sauerbrey equation was applied to establish the correlation between the QCM frequency changes measured after exposure to different NO 2 concentrations and the mass-loading of the QCM. The experiments were carried out in a dynamic mode on a special laboratory setup with complete control of the process parameters. The TiO 2 films were tested in the NO 2 concentration interval from 10 ppm to 5000 ppm. It was found that a TiO 2 loading of the QCM by 5.76 kHz corresponded to a system sensitive to NO 2 concentrations above 250 ppm. On the basis of the frequency-time characteristics (FTCs) measured, AF at different NO 2 concentrations was defined, the adsorption/desorption cycles were studied and the response and recovery times were estimated. The results obtained show that the process is reversible in the NO 2 interval investigated. The results further suggested that TiO 2 films prepared by a sol-gel method on a QCM can be used as a sensor element for NO 2 detection.

  5. Formation and optical characteristics of sol-gel derived highly oriented ferroelectric (Sr,Ba)Na2O6 optical waveguide thin films

    International Nuclear Information System (INIS)

    Koo, Jun Mo; Kang, Eun Seok; Bae, Byeong Soo

    2003-01-01

    Highly c-axis oriented SBN thin films with various compositions were obtained by sol-gel process. The preferential orientation of sol-gel derived film was enhanced by poling the film with high dc electric field, and growing the film on seeded MgO substrate. The mechanisms of these methods were discussed in this study. For their optical waveguide applications, the optical properties of SBN thin films were investigated. The anisotropy of refractive indices (n o and n e ) of the oriented films decreased certainly as Sr content in the film composition increased

  6. Photocatalytic degradation of Lissamine Green B dye by using nanostructured sol–gel TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Ćurković, Lidija, E-mail: lcurkov@fsb.hr [Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb (Croatia); Ljubas, Davor [Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb (Croatia); Šegota, Suzana [Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb (Croatia); Bačić, Ivana [Forensic Science Centre Ivan Vučetić, Ministry of the Interior, Ilica 335, Zagreb (Croatia)

    2014-08-01

    Highlights: • Nanostructured photocatalytic TiO{sub 2} films were prepared by sol–gel methods. • The addition of PEG to the TiO{sub 2} film changes the surface morphology and roughness parameters. • The addition of PEG to the initial sols increases photocatalytic properties of TiO{sub 2}. • LGB water solution could be decolourised within 2 h. • The influence of photolysis and adsorption on the LGB removal from the solution is negligible. - Abstract: Nanostructured sol–gel TiO{sub 2} films were prepared on a glass substrate by means of the dip-coating technique with titanium tetraisopropoxide as a precursor. TiO{sub 2} sols were synthesized with and without the addition of polyethylene glycol (PEG) as a structure-directing agent. The synthesized sol–gel TiO{sub 2} were characterized by XRD, AFM, FTIR and Micro-Raman spectroscopy. The photocatalytic activity of the films was evaluated by the photocatalytic degradation of Lissamine Green B (LGB) dye (dissolved in water) as a model pollutant with the predominant irradiation wavelength of 365 nm (UV-A). It was found that the addition of PEG to the initial sol affects the surface morphology and the photocatalytic properties of prepared sol–gel TiO{sub 2} films. AFM analysis confirmed the presence of nanostructured sol–gel titania films on the glass substrate. Roughness parameters (R{sub a}, R{sub q}, and Z{sub max}) of the sol–gel TiO{sub 2} film with the addition of PEG are higher than the parameters of the sol–gel TiO{sub 2} film without the addition of PEG. The TiO{sub 2} film prepared with the addition of PEG has a higher surface density (a larger active surface area) and better photocatalytic activity in the degradation of the LGB dye solution than the TiO{sub 2} film prepared without the addition of PEG.

  7. Characterization of ITO Thin Films Prepared by Sol-gel Spin-Coating Technique

    Directory of Open Access Journals (Sweden)

    Mokhtar HJIRI

    2014-05-01

    Full Text Available Indium tin oxide (ITO thin films have been prepared on glass substrate using sol-gel spin-coating technique with different dopant concentrations. The sol was prepared using 2- methoxyethanol and triethylamine (TEA as a solvent and stabilizer, respectively. Indium chloride (InCl3 was used as a precursor and tin chloride (SnCl2, 2H2O as a doping source. X-ray diffraction result indicates that the ITO thin films have the polycrystalline structure. The optical transmittance spectrum indicates the average transmittance higher than 80 % in visible region. The band gap energy is varied between 3.5 and 4.0 eV. From AFM analysis, we can show that all films have a good roughness. Four point method indicates that the sample with doping concentration of 5 % at. Has the lowest sheet resistance (277 W/Sq. From characterization results, it’s clear that the obtained samples are promising for gas detection.

  8. Sol-gel coatings: An alternative route for producing planar optical waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Rey-Garcia, F.; Gomez-Reino, C. [Unidad Asociada de Optica and Microoptica GRIN (CSIC-ICMA), Departamento de Fisica Aplicada, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, Campus Sur s/n, E-15782 Santiago de Compostela (Spain); Flores-Arias, M.T., E-mail: maite.flores@usc.es [Unidad Asociada de Optica and Microoptica GRIN (CSIC-ICMA), Departamento de Fisica Aplicada, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, Campus Sur s/n, E-15782 Santiago de Compostela (Spain); De La Fuente, G.F., E-mail: xerman@unizar.es [Instituto de Ciencia de Materiales de Aragon (CSIC-Universidad de Zaragoza), Maria de Luna 3, E-50018 Zaragoza (Spain); Duran, A. [Instituto de Ceramica y Vidrio (CSIC), Kelsen 5, E-28049, Madrid (Spain); Castro, Y., E-mail: castro@icv.csic.es [Instituto de Ceramica y Vidrio (CSIC), Kelsen 5, E-28049, Madrid (Spain)

    2011-09-01

    Inorganic and hybrid planar waveguides with different compositions (silica-titania, methacrylate-silica-cerium oxide, zirconia-cerium oxide and silica-zirconia) have been obtained by sol-gel synthesis followed by dip-coating. Soda-lime glass slides and conventional commercial window glass were used as substrates. The thickness and refractive index of the coatings were determined by profilometry and Spectroscopic Ellipsometry. Waveguide efficiency was measured at ca. 70.8% with a He-Ne laser beam, coupled with an optical microscope objective into and out of the waveguiding layer via a double prism configuration. Thicknesses between 150 and 2000 nm, along with refractive index values ranging between 1.45 and {approx} 1.99 ({lambda} = 633 nm) were obtained depending on the sol composition and the dip-coating conditions. This wide range of values allows designing multilayered guides that can be used in a variety of applications.

  9. High Refractive Organic–Inorganic Hybrid Films Prepared by Low Water Sol-Gel and UV-Irradiation Processes

    Directory of Open Access Journals (Sweden)

    Hsiao-Yuan Ma

    2016-03-01

    Full Text Available Organic-inorganic hybrid sols (Ti–O–Si precursor were first synthesized by the sol-gel method at low addition of water, and were then employed to prepare a highly refractive hybrid optical film. This film was obtained by blending the Ti–O–Si precursor with 2-phenylphenoxyethyl acrylate (OPPEA to perform photo-polymerization by ultraviolet (UV irradiation. Results show that the film transparency of poly(Ti–O–Si precursor-co-OPPEA film is higher than that of a pure poly(Ti–O–Si precursor film, and that this poly(Ti–O–Si precursor-co-OPPEA hybrid film exhibits a high transparency of ~93.7% coupled with a high refractive index (n of 1.83 corresponding to a thickness of 2.59 μm.

  10. Optical and sensing properties of sol-gel derived vanadium pentoxide thin films with porous and dense structures

    Science.gov (United States)

    Babeva, T.; Awala, H.; Grand, J.; Lazarova, K.; Vasileva, M.; Mintova, S.

    2018-03-01

    The sol-gel and spin-coating methods were used for deposition of thin transparent V2O5 films on optical glass substrates and silicon wafers. Different synthesis and deposition conditions, including synthesis temperatures and post-deposition annealing, were used aiming at obtaining transparent films with high refractive index and good optical quality. The surface morphology and structure of the films were studied by SEM and XRD. The optical properties (refractive index, extinction coefficient and optical band gap) and thickness of the V2O5 films were determined from their transmittance and reflectance spectra. The potential application of the films as building blocks of optical sensors was demonstrated by preparation of multilayered structures comprising both V2O5 and BEA-type zeolite films and testing their response towards acetone vapors.

  11. In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

    Directory of Open Access Journals (Sweden)

    Junsheng Wu

    2017-04-01

    Full Text Available A layered double hydroxide (LDH film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM. The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS, scanning electrochemical microscopy (SECM, and a salt-spray test (SST.The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film.

  12. Structural and optical properties of sol-gel deposited proton conducting Ta{sub 2}O{sub 5} films

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, N.; Lampert, C.M.

    1995-08-01

    Proton conducting tantalum oxide films were deposited by spin coating using a sol-gel process. The coating solutions were prepared using Ta(OC{sub 2}H{sub 5}){sub 5} as a precursor. X-ray diffraction studies determined that the sol-gel films, heat treated at temperatures below 400 C, were amorphous. Films heat treated at higher temperatures were crystalline Ta{sub 2}O{sub 5}. The solar transmission values (T{sub s}) of tantala films on glass generally range from 0.8--0.9 depending on thickness. The refractive index and the extinction coefficient were evaluated from transmittance characteristics in the UV-VIS-NIR regions. The refractive index values calculated at 550 nm increased from 1.78 to 1.97 with increasing heat treatment from 150 to 450 C. The films heat treated at different temperatures showed low absorption with extinction coefficients of less than k=1x10{sup -3} in the visible range. Spectrophotometric and impedance spectroscopic investigations performed on Ta{sub 2}O{sub 5} films revealed that these films have protonic conductivity of 3.2x10{sup -6} S/cm. The films are suitable for proton conducting layers in electrochromic (EC) devices.

  13. Photocatalytic and photoelectrochemical properties of sol–gel TiO2 films of controlled thickness and porosity

    Czech Academy of Sciences Publication Activity Database

    Krýsa, J.; Baudyš, M.; Zlámal, M.; Krýsová, Hana; Morozová, Magdalena; Klusoň, Petr

    2014-01-01

    Roč. 230, JUL 2014 (2014), s. 2-7 ISSN 0920-5861 Institutional support: RVO:61388955 ; RVO:67985858 Keywords : TiO2 film * Sol-gel * Thickness Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  14. Epoxy catalyzed sol–gel method for pinhole-free pyrite FeS.sub.2./sub. thin films

    Czech Academy of Sciences Publication Activity Database

    Kment, Štěpán; Kmentová, Hana; Sarkar, A.; Soukup, R. J.; Ianno, N.J.; Sekora, D.; Olejníček, Jiří; Kšírová, Petra; Krysa, J.; Remeš, Zdeněk; Hubička, Zdeněk

    2014-01-01

    Roč. 607, Sep (2014), s. 169-176 ISSN 0925-8388 R&D Projects: GA MŠk LH12043 Grant - others:AV ČR(CZ) M100101215 Institutional support: RVO:68378271 ; RVO:67985858 Keywords : heterojunction * photoelectrochemical solar cells * sol-gel * thin films Subject RIV: JJ - Other Materials Impact factor: 2.999, year: 2014

  15. Fabrication, characterization and sensing properties of Cu(II) ion imprinted sol–gel thin film on QCM

    International Nuclear Information System (INIS)

    Su, Pi-Guey; Hung, Fang-Chieh; Lin, Po-Hung

    2012-01-01

    Cu(II)-molecularly imprinted sol–gel films (Cu(II)-MISGF), coated on a quartz crystal microbalance (QCM) chip, were fabricated using a sol–gel procedure. Co-hydrolysis and co-condensation of Cu(II) (templates), 3-aminopropyltrimethoxysilane (APTS, functional monomer) and tetraethoxysilane (TEOS, cross-linking agent) were performed with acid and base catalysis. The properties of the Cu(II)-MISGF were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and the electrochemical methods of cyclic voltammetry (CV). Microstructural observations revealed that the acid-catalyzed system yielded more mechanically stable thin films. A combined Cu(II)-MISGF-QCM with flow injection analysis (FIA) method was utilized to investigate the sensing performance of the Cu(II)-MISGF, with special emphasis on the most important properties of sensitivity, selectivity and response time. The Cu(II)-MISGF-QCM sensor, at a TEOS/APTS molar ratio of 10, exhibited excellent selectivity and rapidly responded to Cu(II) ions. - Highlights: ► A Cu(II)-molecularly imprinted sol–gel thin film on chip was fabricated. ► The thin film had mechanical stability using acidic catalyst. ► The thin film had good selectivity and response time for Cu(II) ions.

  16. Magnetic behaviour of sol–gel driven BiFeO{sub 3} thin films with different grain size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shiwani [School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India); Saravanan, P. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Pandey, O.P. [School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India); Vinod, V.T.P.; Černík, Miroslav [Institute for Nanomaterials, Advanced Technologies and Innovation, Department of Natural Sciences, Technical University of Liberec, Studentská 1402/2, Liberec 1, 461 17 (Czech Republic); Sharma, Puneet, E-mail: puneet.sharma@thapar.edu [School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India)

    2016-03-01

    BiFeO{sub 3} (BFO) thin films with uniform thickness of ~200 nm were prepared by the sol–gel assisted spin coating method. Different grain size distributions in the as-grown BFO films were then induced by varying the annealing temperature between 525 and 600 °C. It is found that the grain size distribution become wider as the annealing temperature increases. All the films showed a well-saturated magnetization (M) versus magnetic field (H) hysteresis loops at 300 K. A strong dependence of M on the grain size distribution is observed. An optimal grain size distribution with average grain size ~90 nm is responsible for high M in the BFO films. The non-saturated M–H loops obtained at 10 K suggest the spin glass behaviour of BFO films. The zero field cooled (ZFC) and field cooled (FC) magnetization curves shows split at 300 K and a cusp at ~50 K in the ZFC curve, which further confirms the spin glass state of polycrystalline BFO thin films. - Highlights: • Effect of grain size distribution on magnetization of bismuth ferrite was investigated. • BiFeO{sub 3} thin films of uniform thickness with different grain size distribution were prepared by the sol–gel method. • Strong dependence of magnetization on grain size distribution is observed.

  17. Thermally activated charge transport in modified tetragonal zirconia thin films prepared by sol-gel method

    Science.gov (United States)

    Aboulkacem, Khiali; Abdelkader, Ammari; Bediaf, Benrabah; Amar, Bouaza; Abdelmalek, Kharoubi; Hadj, Benhebal

    2018-04-01

    Films of Sn-doped ZrO2 were prepared using the sol-gel based dip-coating technique. The X-ray diffraction patterns showed a tetragonal structure with a preferential orientation along the (111) plane. The average grain size of the samples varies from 9.53 to 12.64 nm. Thermal analysis revealed endothermic peaks in the range 84-90 °C and exothermic peaks appearing in the range 489-531 °C. Fourier transform infrared (FTIR) spectra depicted bands located at 612 and 736 cm-1, which are attributed to stretching mode and asymmetric vibrations of Zr-O and O-Zr-O bonds respectively. All films exhibited high transmittance in the visible range above 60% and the optical band gap (E g) decreases from 4.085 to 4.061 eV. The impedance measurements show that the equivalent circuit of the samples is an R p C p where C p is the capacitance of the layer and R p its resistance. The electrical conductivity was found to follows an Arrhenius law with two activation energies.

  18. Formulation and in vitro/in vivo evaluation of chitosan-based film forming gel containing ketoprofen.

    Science.gov (United States)

    Oh, Dong-Won; Kang, Ji-Hyun; Lee, Hyo-Jung; Han, Sang-Duk; Kang, Min-Hyung; Kwon, Yie-Hyuk; Jun, Joon-Ho; Kim, Dong-Wook; Rhee, Yun-Seok; Kim, Ju-Young; Park, Eun-Seok; Park, Chung-Woong

    2017-11-01

    The film forming gel, adhered to skin surfaces upon application and formed a film, has an advantage onto skin to provide protection and continuous drug release to the application site. This study aimed to prepare a chitosan-based film forming gel containing ketoprofen (CbFG) and to evaluate the CbFG and film from CbFG (CbFG-film). CbFG were prepared with chitosan, lactic acid and various skin permeation enhancers. The physicochemical characteristics were evaluated by texture analysis, viscometry, SEM, DSC, XRD and FT-IR. To identify the mechanism of skin permeation, in vitro skin permeation study was conducted with a Franz diffusion cell and excised SD-rat and hairless mouse dorsal skin. In vivo efficacy assessment in mono-iodoacetate (MIA)-induced rheumatoid arthritis animal model was also conducted. CbFG was successfully prepared and, after applying CbFG to the excised rat dorsal skin, the CbFG-film was also formed well. The physicochemical characteristics of CbFG and CbFG-film could be explained by the grafting of oleic acid onto chitosan in the absence of catalysts. In addition, CbFG containing oleic acid had a higher skin permeation rate in comparison with any other candidate enhancers. The in vivo efficacy study also confirmed significant anti-inflammatory and analgesic effects. Consequently, we report the successful preparation of chitosan-based film forming gel containing ketoprofen with excellent mechanical properties, skin permeation and anti-inflammatory and analgesic effects.

  19. Fabrication of Meso-Porous Gamma-Alumina Films by Sol-Gel and Gel Casting Processes for Making Moisture Sensors

    Directory of Open Access Journals (Sweden)

    Kalyan Kumar Mistry

    2007-04-01

    Full Text Available Meso-porous g-Al2O3 film may be used as a highly sensitive trace moisture sensor. The crack-free alumina film was developed using a combination of sol-gel and tape casting processes, which produce high porosity, high surface area and small pore dimensions in the range of few nano-meter at uniform distribution. Sol-gel processes are well known in nano-technology and nano-material preparation, but it is difficult to make crack-free thick or thin films using this method. Tape cast methods are used for the fabrication of flexible crack-free thick ceramic sheets. Our objective was to develop nano-structured, crack-free, transparent Al2O3 film a few microns thick, has a highly porous and stable crystallographic nature. A metallic paste was printed by screen printing on both side of the film surface for electrodes to form a sensitive element. A silver wire (dia j=0.1mm lead was connected to a grid structure electrode using a silver paste spot for fine joining. Alumina is absorbs moisture molecules into its meso-porous layer and changes its electrical characteristics according to the moisture content, its dielectric constant increase as moisture increase. Moisture molecules can be conceived of as dipoles in random state before the application of an electric field. When the dipole orientation was changed from random to an equilibrium state under the application of external field, a large change in dielectric constant was observed. The number of water molecules absorbed determines the electrical impedance of the capacitor, which in turn is proportional to water vapor pressure.

  20. Up-conversion emission in rare earth-doped Y2Ti2O7 sol-gel thin films

    International Nuclear Information System (INIS)

    Jenouvrier, P.; Boccardi, G.; Fick, J.; Jurdyc, A.-M.; Langlet, M.

    2005-01-01

    Yttrium titanate (YTO) thin films doped with rare earth elements have been deposited using the aerosol-gel process. The up-conversion emission (UPE) of films doped with erbium and/or thulium has been studied with respect to the film crystallization degree and rare earth concentration. The effects of ytterbium codoping have been considered as well. Mechanisms that control UPE of YTO films are discussed with respect to the experimental conditions. It is shown that films, which selectively emit in the blue ( 1 G 4 → 3 H 6 transition of thulium ions), green ( 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions of erbium ions), or red ( 4 F 9/2 → 4 I 15/2 transition of erbium ions), can readily be achieved

  1. Production and characterization of LaMnO3 thin films prepared by Sol–Gel technique

    Directory of Open Access Journals (Sweden)

    M. Faruk Ebeoğlugil

    2017-04-01

    Full Text Available In this study, lanthanum manganite (LaMnO3 thin films were prepared by sol-gel method for magnet technology. With this context, precursor solutions with low contact angles were synthesized from all nitrate salts of the respective cations (La, Mn, using ethanol as solvent and acetyl acetone as chelating agents. A dense amorphous film was deposited on silicon (Si substrate. Crystallization of the films was carried out at temperatures between 850 and 1000 °C. The thermal, phase, elemental, microstructural and magnetic properties of the obtained samples were determined by TG/DTA, FTIR, XRD, XPS, SEM and VSM. The results show that sustained perovskite polycrystalline films were grown on the [100]-oriented Si substrates. In addition, the films show ferromagnetic behavior.

  2. Effect of Aging Time and Film Thickness on the Photoelectrochemical Properties of TiO2 Sol-Gel Photoanodes

    Directory of Open Access Journals (Sweden)

    D. Regonini

    2014-01-01

    Full Text Available This work has focused on the investigation of a non-aqueous based sol-gel process to produce TiO2 based photoelectrodes for solar water splitting. In particular, the effect of the aging time of the sol and TiO2 film thickness on the photoelectrochemical properties of the photoanodes has been investigated. In order to achieve optimal performances (i.e., photocurrent density up to 570 µA/cm2 and IPCE of 26% at 300 nm, the sol needs to be aged for 3 to 6 h, before being dip-coated to produce the photoanodes. The importance of the aging time can also be appreciated from the optical properties of the TiO2 films; the absorbance threshold of the sol-gel aged for 3–6 h is slightly shifted towards longer wavelenghts in comparison to 0 h aging. Aging is necessary to build up a well-interconnected sol-gel network which finally leads to a photoelectrode with optimized light absorption and electron collection properties. This is also confirmed by the higher IPCE signal of aged photoelectrodes, especially below 340 nm. Among thicknesses considered, there is no apparent significant difference in the photoresponse (photocurrent density and IPCE of the TiO2 sol-gel films.

  3. Study of the gel films of Acetobacter Xylinum cellulose and its modified samples by {sup 1}H NMR cryoporometry and small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Babushkina, T. A.; Klimova, T. P. [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Shtykova, E. V.; Dembo, K. A.; Volkov, V. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Khripunov, A. K. [Russian Academy of Sciences, Institute of Macromolecular Compounds (Russian Federation); Klechkovskaya, V. V., E-mail: klechvv@ns.crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2010-03-15

    Gel films of Acetobacter Xylinum cellulose and its modified samples have been investigated by 1H nuclear magnetic resonance (NMR) cryoporometry and small-angle X-ray scattering. The joint use of these two methods made it possible to characterize the sizes of aqueous pores in gel films and estimate the sizes of structural inhomogeneities before and after the sorption of polyvinylpyrrolidone and Se{sub 0} nanoparticles (stabilized by polyvinylpyrrolidone) into the films. According to small-angle X-ray scattering data, the sizes of inhomogeneities in a gel film change only slightly upon the sorption of polyvinylpyrrolidone and nanoparticles. The impregnated material is sorbed into water-filled cavities that are present in the gel film. {sup 1}H NMR cryoporometry allowed us to reveal the details of changes in the sizes of small aqueous pores during modifications.

  4. Effect of boron doping on optical properties of sol–gel based nanostructured zinc oxide films on glass

    International Nuclear Information System (INIS)

    Jana, Sunirmal; Vuk, Angela Surca; Mallick, Aparajita; Orel, Boris; Biswas, Prasanta Kumar

    2011-01-01

    Graphical abstract: Room temperature fine structured UV–vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: ► Sol–gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. ► Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). ► Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. ► The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films (∼80 nm) were deposited onto pure silica glass by sol–gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24–2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

  5. Microstructure and magnetism of sol–gel synthesized Co-doped PbPdO{sub 2} nanograin film

    Energy Technology Data Exchange (ETDEWEB)

    Song, T.T.; Tang, F.L. [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Su, H.L., E-mail: hailinsu@hfut.edu.cn [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Chuang, P.Y. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Liu, J.; Mei, C. [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Huang, S.Y. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Lee, M.K. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); MoST Instrument Center at NCKU, Tainan 70101, Taiwan (China); Huang, J.C.A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (China); Wu, Y.C., E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China)

    2016-06-01

    The single-phase body-centered-orthorhombic-structured Co-doped PbPdO{sub 2} thin film was obtained using the sol–gel spin-coating method and an oxidation treatment. The film had a nanograin microstructure with an average grain size of about 56 nm and a thickness of about 150 nm. The adoption of a moderate calcination temperature of 650 °C was found to be very important for preparing the single-phase-PbPdO{sub 2}-based film with a high crystalline quality. The magnetic studies exhibited that the ferromagnetism and the paramagnetism coexist within the formed Co-doped PbPdO{sub 2} film and the ferromagnetism can be maintained above room temperature. The saturation magnetization of the ferromagnetism increasing with the temperature, as the peculiar characteristic of the spin gapless semiconductor, was found within the film. The investigation on the film's X-ray absorption near-edge structure revealed that the ferromagnetism of the Co-doped PbPdO{sub 2} is intrinsic. - Highlights: • High-quality single-phase body-centered-orthorhombic-structured Co-doped PbPdO{sub 2} nanograin film was synthesized by the sol–gel spin-coating method and an oxidation treatment. • The magnetic constitution of Co-doped PbPdO{sub 2} nanograin film was clarified. • The saturation magnetization of the ferromagnetism increasing with the temperature, as the peculiar characteristic of the spin gapless semiconductor, was found within the Co-doped PbPdO{sub 2} nanograin film. • The obtained ferromagnetism can be retained to high temperature and was demonstrated to be intrinsic.

  6. Growth and characterization of sol-gel derived CuGaO2 semiconductor thin films for UV photodetector application

    Science.gov (United States)

    Tsay, Chien-Yie; Chen, Ching-Lien

    2017-06-01

    In this study, a p-type wide-bandgap oxide semiconductor CuGaO2 thin film was grown on quartz substrate by sol-gel method. The authors report the influence of annealing temperature on the phase transformation, structural features, and electrical properties of sol-gel derived Cu-Ga-O thin films. At relatively low annealing temperatures (≤900 °C), the films are a mixture of CuGa2O4, CuGaO2, and CuO phases. At relatively high annealing temperatures (≥925 °C), the majority phase in the films is delafossite CuGaO2. All as-prepared Cu-Ga-O thin films exhibited p-type conductivity, as confirmed by Hall measurements. The mean electrical resistivity of the Cu-Ga-O films decreased from 3.54×104 Ω-cm to 1.35×102 Ω-cm and then increased slightly to 3.51×102 Ω-cm when the annealing temperature was increased from 850 °C to 950 °C. We found that annealing the Cu-based oxide thin films at 925 °C produced nearly phase-pure CuGaO2 thin films with good densification. Such thin films exhibited the best electrical properties: a mean electrical resistivity of 1.35×102 Ω-cm, and a mean hole concentration of 1.60×1016 cm-3. In addition, we also fabricated and characterized MSM-type CuGaO2 UV photodetectors on quartz substrates.

  7. Feedback mode SECM study of laccase and bilirubin oxidase immobilised in a sol-gel processed silicate film.

    Science.gov (United States)

    Nogala, Wojciech; Szot, Katarzyna; Burchardt, Malte; Roelfs, Folkert; Rogalski, Jerzy; Opallo, Marcin; Wittstock, Gunther

    2010-08-01

    Thin silicate films with immobilised enzymes catalysing dioxygen reduction, i.e. laccase and bilirubin oxidase (BOD), were deposited on glass and poly(methyl 2-methylpropenoate) (Plexiglas) surfaces in a sol-gel process by sol drop evaporation. Scanning electrochemical microscopy (SECM) images and approach curves were recorded using hexacyanoferrate(iii) as mediator in the feedback mode. Confocal laser scanning microscopy (CLSM) images in the reflection mode showed larger film thickness close to the edge of the film and laccase aggregates within the film. SECM images obtained using different dioxygen concentrations showed that the film edge and laccase aggregates exhibit higher enzymatic activity towards dioxygen reduction. SECM current-distance curves enabled the determination of kinetic information at the particular regions of the samples after numerical fitting of model parameters. The heterogeneous first order rate constant at the film border was estimated to be ca. 19 times higher than the value obtained when approaching to the centre of the film. The reason of higher laccase surface concentration at the film edge is carefully discussed. For comparison of laccase and BOD activities, silicate spots of 50 microm diameter were deposited on a single Plexiglas sample and examined using SECM. BOD exhibits much higher activity especially at neutral pH.

  8. Effect of cobalt doping and annealing on properties of titania thin films prepared by sol-gel process

    Science.gov (United States)

    Pärna, R.; Joost, U.; Nõmmiste, E.; Käämbre, T.; Kikas, A.; Kuusik, I.; Hirsimäki, M.; Kink, I.; Kisand, V.

    2011-05-01

    Undoped and cobalt doped titania (TiO 2) thin films have been prepared on Si(1 0 0) monocrystal and quartz substrate using the sol-gel deposition method and annealed in air at 450, 550, 650, 750, 850, 950 and 1050 °C. Several experimental techniques (AFM, XRD, Raman spectroscopy, XRR, EDX, XPS, XAS, UV-VIS spectroscopy) have been used to characterize these films. Further more the degree of light induced hydrophilicity was estimated by measuring the contact angle of a water droplet on the film. Increase of the annealing temperature and in smaller degree also cobalt doping predispose titania crystallite growth. The rutile phase was detected at lower temperatures in the cobalt doped films than in the undoped titania films. Cobalt in the cobalt doped TiO 2 was seen to be in Co 2+ oxidation state, mainly in CoTiO 3 phase when films were annealed at temperatures higher than 650 °C. Cobalt compounds segregated into the sub-surface region and to the surface of the titania, where they formed islands. Cobalt doping red-shifted the fundamental absorption edge further into the visible range, however it did not enhance the light induced hydrophilicity of the thin film surface as compared to the undoped titania thin films.

  9. Sb doping effects and oxygen adsorption in SnO2 thin films deposited via sol-gel

    Directory of Open Access Journals (Sweden)

    Viviany Geraldo

    2003-12-01

    Full Text Available Transparent electrically conducting antimony-doped SnO2 thin films have been prepared by sol-gel dip-coating process from colloidal aqueous suspension. The effect of doping content on the structural, optical and electrical properties is analyzed. Results from infrared optical transmission and reflection have shown that the higher the Sb concentration the lower the transmission intensity and the higher the reflection signal. Absorption intensity increases as well. Results of X-ray reflectometry and electron microscopy have shown that the density of films fired at 400 °C after each dip is higher than that of multi-dipped films prepared with a single annealing. Both the electrical characteristics in the dark and the increase in conductivity as function of illumination through different filters, at 190 K, evidence that the transport properties of these films are dominated by the presence of defects, including the trapping at grain boundary due to excess of oxygen.

  10. Sensing CO gas with SnO{sub 2} thin films wetted with Cu prepared by sol-gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Tirado G, S.; Cazares R, J. M. [Escuela Superior de Fisica y Matematicas, IPN, A. P. 75-544, 07300 Mexico D. F. (Mexico); Maldonado, A. [Departamento de Ingenieria Electrica, Centro de Investigacion y de Estudios Avanzados, IPN, A. P. 14-740, 07000 Mexico D. F. (Mexico)

    2009-10-15

    Pure and Cu surface deposited SnO{sub 2} thin films have been prepared on soda-lime substrate using the sol-gel technique. The sensing CO gas properties were investigated in 230 nm in thickness thin films. Pure thin films were wetted with several layers of Cu. The sensors were fabricated and proved at 0, 1, 5, 50, 100 and 200 ppm concentration CO gas and at 23, 100, 200 and 300 C working temperatures. The structural, morphology, electrical and optical properties of such thin films are reported. The route of 2-methoxyethanol and monoethanolamine was used. The resistance was high for all the samples. As was proposed, all the samples resulted enough amorphous and so the X-ray diffraction spectra show such structural state. the surface morphology for the samples was characterized by SEM and also by AFM techniques. (Author)

  11. Thermal Conductivity of a Nanoscale Yttrium Iron Garnet Thin-Film Prepared by the Sol-Gel Process.

    Science.gov (United States)

    Kim, Yun Young

    2017-08-31

    The thermal conductivity of a nanoscale yttrium iron garnet (Y₃Fe₅O 12 , YIG) thin-film prepared by a sol-gel method was evaluated using the ultrafast pump-probe technique in the present study. The thermoreflectance change on the surface of a 250 nm thick YIG film, induced by the irradiation of femtosecond laser pulses, was measured, and curve fitting of a numerical solution for the transient heat conduction equation to the experimental data was performed using the finite difference method in order to extract the thermal property. Results show that the film's thermal conductivity is 22-83% higher than the properties of bulk YIG materials prepared by different fabrication techniques, reflecting the microstructural characteristics and quality of the film.

  12. Atomic force microscopy study of TiO2 sol-gel films thermally treated under NH3 atmosphere

    International Nuclear Information System (INIS)

    Trapalis, C.; Todorova, N.; Anastasescu, M.; Anastasescu, C.; Stoica, M.; Gartner, M.; Zaharescu, M.; Stoica, T.

    2009-01-01

    Multilayered TiO 2 films were obtained by sol-gel and dipping deposition on quartz substrate followed by thermal treatment under NH 3 atmosphere. In an attempt to understand the close relationship between microstructural characteristics and the synthesis parameters, a systematic research of the structure and the morphology of NH 3 modified TiO 2 sol-gel films by XRD and Atomic Force Microscopy is reported. The surface morphology has been evaluated in terms of grains size, fractal dimension and surface roughness. For each surface, it was found a self-similar behavior (with mean fractal dimension in the range of 2.67-3.00) related to an optimum morphology favorable to maintain a nano-size distribution of the grains. The root mean square (RMS) roughness of the samples was found to be in the range of 0.72-6.02 nm.

  13. Thickness controlled sol-gel silica films for plasmonic bio-sensing devices

    Energy Technology Data Exchange (ETDEWEB)

    Figus, Cristiana, E-mail: cristiana.figus@dsf.unica.it; Quochi, Francesco, E-mail: cristiana.figus@dsf.unica.it; Artizzu, Flavia, E-mail: cristiana.figus@dsf.unica.it; Saba, Michele, E-mail: cristiana.figus@dsf.unica.it; Marongiu, Daniela, E-mail: cristiana.figus@dsf.unica.it; Mura, Andrea; Bongiovanni, Giovanni [Dipartimento di Fisica - University of Cagliari, S.P. Km 0.7, I-09042 Monserrato (Canada) (Italy); Floris, Francesco; Marabelli, Franco; Patrini, Maddalena; Fornasari, Lucia [Dipartimento di Fisica - University of Pavia, Via Agostino Bassi 6, I-27100 Pavia (PV) (Italy); Pellacani, Paola; Valsesia, Andrea [Plasmore S.r.l. -Via Grazia Deledda 4, I-21020 Ranco (Vatican City State, Holy See) (Italy)

    2014-10-21

    Plasmonics has recently received considerable interest due to its potentiality in many fields as well as in nanobio-technology applications. In this regard, various strategies are required for modifying the surfaces of plasmonic nanostructures and to control their optical properties in view of interesting application such as bio-sensing, We report a simple method for depositing silica layers of controlled thickness on planar plasmonic structures. Tetraethoxysilane (TEOS) was used as silica precursor. The control of the silica layer thickness was obtained by optimizing the sol-gel method and dip-coating technique, in particular by properly tuning different parameters such as pH, solvent concentration, and withdrawal speed. The resulting films were characterized via atomic force microscopy (AFM), Fourier-transform (FT) spectroscopy, and spectroscopic ellipsometry (SE). Furthermore, by performing the analysis of surface plasmon resonances before and after the coating of the nanostructures, it was observed that the position of the resonance structures could be properly shifted by finely controlling the silica layer thickness. The effect of silica coating was assessed also in view of sensing applications, due to important advantages, such as surface protection of the plasmonic structure.

  14. Sb doping effects and oxygen adsorption in SnO2 thin films deposited via sol-gel

    OpenAIRE

    Viviany Geraldo; Luis Vicente de Andrade Scalvi; Evandro Augusto de Morais; Celso Valentim Santilli; Sandra Helena Pulcinelli

    2003-01-01

    Transparent electrically conducting antimony-doped SnO2 thin films have been prepared by sol-gel dip-coating process from colloidal aqueous suspension. The effect of doping content on the structural, optical and electrical properties is analyzed. Results from infrared optical transmission and reflection have shown that the higher the Sb concentration the lower the transmission intensity and the higher the reflection signal. Absorption intensity increases as well. Results of X-ray reflectometr...

  15. Analysis Crystal Structure of Thin Films Bazr0.2ti0.8o3 Which Have Deposited by Sol Gel Method

    OpenAIRE

    I., Yofentina; V., Viska I; Hikam, M; S., Bambang; M., Alfan; P., Wahyu

    2011-01-01

    Fabrication of BaZr0.2Ti0.8O3 thin film on Si substrate by sol gel method use spin coater has been done successfully. Bariumasetat, zirconiumisoproponol, titaniumisopropoksid were used as deposition components BZT thin film. Asetat acid and etylen glycol were used as solvent. There are three basic principles of thin film fabrication by sol gel method, i.e. chemical process (Solvent fabrication), thin film deposition use spin coater, and thermal process (annealing). The layers number variation...

  16. Investigation of the Spatial Resolution of MR-Based Polymer Gel Dosimetry versus Film Densitometry using Dose Modulation Transfer Function

    Directory of Open Access Journals (Sweden)

    Reza Moghadam-Drodkhani

    2011-03-01

    Full Text Available Introduction: The conventional methods of dosimetry are not capable of dosimetry in such a small volume of less than one cubic millimeter. Although the polymer gel dosimetry method based on magnetic resonance imaging (MRI could achieve three dimensional dosimetry with high resolution, a spatial resolution evaluation based on gel dose modulation transfer function has not been investigated yet. Therefore, in this study, the spatial resolution of two systems of film densitometry and polymer gel dosimetry based on MRI has been evaluated by using the dose modulation transfer function (DMTF.   Material and Methods: Kodak therapy verification films and MAGICA polymer gel samples were positioned below a brass absorption grid with different periodic slices (a/2= 280, 525, 1125 μm, which was placed in a water bath container to avoid regions of dose build-up just below the absorption grid and then irradiated with Cobalt-60 photons on a Theratron external-beam treatment unit. Dose variation under the brass grid was determined using a calibration curve, while transverse relaxation time (T2 as the selective parameter in a dose image based on multiple echo MRI with 1.5 Tesla GE Signa Echo Speed system (FOV=10 cm, matrix size=512 ×512, pixel size =0.199×0.199 mm2, TE = 20, 40, 60, 80 ms, TR=4200 ms, NEX = 4, slice thickness=2 mm, gap=1 mm was calculated. DMTF from the modulation depths of T2 and variation in film optical density after calibration would be achieved. The results of polymer gel were compared with film. Results: After deriving the dose distribution profile under the absorption grid, minima and maxima at the smallest period of a = 560 μm could scarcely be resolved, but the modulations due to a=2250 μm and a = 1050 μm grids could be discerned. The modulation depth for a=2250 μm grid was set to 100% and the other modulations were subsequently referred to this maximum modulation. For film densitometry at a = 1050 μm, the modulation depth was

  17. Effect of solvents on sol-gel spin-coated nanostructured Al-doped ZnO thin films: a film for key optoelectronic applications

    Science.gov (United States)

    Kumar, K. Deva Arun; Valanarasu, S.; Kathalingam, A.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.

    2017-12-01

    Aluminum-doped zinc oxide (AZO) thin films were deposited by sol-gel spin coating technique onto the glass substrates using different solvents such as 2-methoxyethanol, methanol, ethanol and isopropanol. Prepared films were characterized by XRD, Raman spectrum, SEM, UV-visible spectrophotometer, photoluminescence (PL) and electrical studies. XRD studies showed that all the prepared films are hexagonal wurtzite structure with polycrystalline nature oriented along (002) direction. SEM images showed uniform particles of size around 60 nm distributed regularly on to the entire glass substrate. EDX analysis confirmed the composition of grown AZO film consisting of Al, Zn and O elements. The prepared films showed highest optical transmittance 94% in the visible range and band gap 3.30 eV. PL spectra for all AZO films showed a strong UV emission peak at 387 nm. The AZO films prepared using isopropanol solvent showed high carrier concentration and low resistivity values as 1.72 × 1020 cm-3 and 2.90 × 10-3 Ω cm, respectively, with high figure of merit ( ϕ) value 8.42 × 10-3 (Ω/sq)-1.

  18. Photonic devices on planar and curved substrates and methods for fabrication thereof

    Energy Technology Data Exchange (ETDEWEB)

    Bartl, Michael H.; Barhoum, Moussa; Riassetto, David

    2016-08-02

    A versatile and rapid sol-gel technique for the fabrication of high quality one-dimensional photonic bandgap materials. For example, silica/titania multi-layer materials may be fabricated by a sol-gel chemistry route combined with dip-coating onto planar or curved substrate. A shock-cooling step immediately following the thin film heat-treatment process is introduced. This step was found important in the prevention of film crack formation--especially in silica/titania alternating stack materials with a high number of layers. The versatility of this sol-gel method is demonstrated by the fabrication of various Bragg stack-type materials with fine-tuned optical properties by tailoring the number and sequence of alternating layers, the film thickness and the effective refractive index of the deposited thin films. Measured optical properties show good agreement with theoretical simulations confirming the high quality of these sol-gel fabricated optical materials.

  19. Influence of ambient gas on the photoluminescence of sol-gel derived TiO2:Sm3+ films

    Science.gov (United States)

    Reedo, Valter; Lange, Sven; Kiisk, Valter; Lukner, Argo; Tätte, Tanel; Sildos, Ilmo

    2005-08-01

    Photoluminescence (PL) of TiO2:Sm3+ thin films was studied at RT. The films were prepared by the sol-gel spin-coating technique or by atomic layer deposition (ALD) followed by ion implantation. The PL was excited with a Nd:YAG pulse laser emitting at 355 nm. The spectrum of PL consists of intense Sm3+-specific emission lines with a well-pronounced fme structure. The influence of different gaseous environments (air, oxygen, nitrogen) or vacuum on the Sm3+ emission was investigated. In the case of a permanent irradiation of sol-gel films in an oxygen-containing environment, the PL intensity increased. The increase was significantly large but slow. The subsequent evacuation of the measurement chamber led to a rapid decrease of the emission below the detection limit. When the oxygen-containing gas was without any intermediate evacuation replaced by nitrogen, the PL intensity descended to an almost vacuum level. The subsequent exposure to oxygen led to a rather fast emission recovery. The ALD-prepared films exhibited a similar but markedly slower response. The fast response observed was attributed to the adsorption of oxygen on the surface, and the slower one, to the diffbsion of oxygen vacancies taking place under the irradiation in the bulk.

  20. Sol-gel synthesis and XPS study of vanadium-hydroquinone oxide bronze films

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenka, V. [Semiconductor Physics Institute, A. Gostauto 11, 01108 Vilnius (Lithuania); Vilnius Pedagogical University, Studentu 39, 08106 Vilnius (Lithuania); Tvardauskas, H.; Grebinskij, S.; Senulis, M.; Pasiskevicius, A. [Semiconductor Physics Institute, A. Gostauto 11, 01108 Vilnius (Lithuania); Volkov, V.; Zakharova, G. [Institute of Solid State Chemistry, Pervomaiskaia 91, 620219 Yekaterinburg (Russian Federation)

    2009-12-15

    A vanadium - hydroquinone oxide bronze has been synthesized by using a sol gel technology. The V{sub 2}O{sub 5} powder, hydrogen peroxide, and hydroquinone C{sub 6}H{sub 4}(OH){sub 2} were used as the starting materials to produce the bronze. At first the vanadium gel was made by the dissolving of vanadium pentoxide powder in hydrogen peroxide at 273 K. Then the solution was heated up to 350 K for the dissociation of peroxide complexes. An aqueous solution of hydroquinone was mixed with the formed gel in molar ratio 0.33:1. In this way the V{sub 2}O{sub 5{+-}}{sub {delta}}.nH{sub 2}O/HQ (HQ-hydroquinone) gel was synthesized. These gels are applied on the Ni pad and dried in an air (wet gel synthesis) or heated up to 580 K in air for 1 h for the water removal from gel (bronze production). The wet gel, as well as a bronze, was investigated by means of XPS method. Analysis of V-O region of XPS spectra shows that vanadium in both cases (wet gel and bronze) is in stable V{sup 5+} state. Oxygen in wet gel can be associated with V ions, hydroxide group and water. In bronze oxygen is connected with V and hydrogen (hydroxide). (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Low-cost growth of magnesium doped gallium nitride thin films by sol-gel spin coating method

    Science.gov (United States)

    Amin, N. Mohd; Ng, S. S.

    2018-01-01

    Low-cost sol-gel spin coating growth of magnesium (Mg) doped gallium nitride (GaN) thin films with different concentrations of Mg was reported. The effects of the Mg concentration on the structural, surface morphology, elemental compositions, lattice vibrational, and electrical properties of the deposited films were investigated. X-ray diffraction results show that the Mg-doped samples have wurtzite structure with preferred orientation of GaN(002). The crystallite size decreases and the surface of the films with pits/pores were formed, while the crystalline quality of the films degraded as the Mg concentration increases from 2% to 6. %. All the Raman active phonon modes of the wurtzite GaN were observed while a broad peak attributed to the Mg-related lattice vibrational mode was detected at 669 cm-1. Hall effect results show that the resistivity of the thin films decreases while the hole concentration and hall mobility of thin films increases as the concentration of the Mg increases.

  2. Study of Optical Humidity Sensing Properties of Sol-Gel Processed TiO2 and MgO Films

    Directory of Open Access Journals (Sweden)

    B. C. Yadav

    2007-04-01

    Full Text Available Paper reports a comparative study of humidity sensing properties of TiO2 and MgO films fabricated by Sol-gel technique using optical method. One sensing element of the optical humidity sensor presented here consists of rutile structured two-layered TiO2 thin film deposited on the base of an isosceles glass prism. The other sensing element consists of a film of MgO deposited by same technique on base of the prism. Light from He-Ne laser enters prism from one of refracting faces of the prism and gets reflected from the glass-film interface, before emerging out from its other isosceles face. This emergent beam is allowed to pass through an optical fiber. Light coming out from the optical fiber is measured with an optical power meter. Variations in the intensity of light caused by changes in humidity lying in the range 5%RH to 95%RH have been recorded. MgO film shows better sensitivity than TiO2 film.

  3. Sol-gel synthesis of ZnO transparent conductive films: The role of pH

    Science.gov (United States)

    Addonizio, Maria Luisa; Aronne, Antonio; Daliento, Santolo; Tari, Orlando; Fanelli, Esther; Pernice, Pasquale

    2014-06-01

    The sol-gel synthesis of undoped and B- or Al-doped ZnO thin films were critically examined with particular reference to the influence of the pH of the reaction medium on some of their specific characteristics, such as thickness, morphology, doping level and optical properties, in view of their application in the photovoltaic field. Using triethanolamine (TEA) as chelating agent, a range of basic pH from 7.66 to 8.76 was explored starting from a very concentrated zinc acetate dehydrate (ZAD) solution in ethanol, [Zn2+] = 1.0 M, and keeping the ZAD/TEA = 1. A more basic environment gives more porous films whose thickness and crystallinity are higher than those achieved at lower pH. It was found that the morphology, as well as the sheet resistance (Rs) of films, depends on both pH and doping. Increasing the pH the Rs decreases for both undoped and doped films. At a certain pH undoped films exhibit a granular microstructure and lower Rs than B- or Al-doped films which exhibit a finer texture, characterized by a lower porosity. Optical properties strongly depend on the pH as well. Increasing the pH, a noticeable blue shift effect was observed, that was attributed mainly to structural changes and to a lesser extent to the Burnstein-Moss effect.

  4. Viscoelasticity of various gel films prepared from solvent-soluble constituents in coal; Sekitanchu no yobai kayoseibun kara sakuseishita shushu no gel maku no nendansei

    Energy Technology Data Exchange (ETDEWEB)

    Takanohashi, T.; Isoda, S.; Doi, S.; Iino, M. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science

    1996-10-28

    Viscoelasticity of gel films prepared from solvent-soluble constituents without ash of coal using the mixed solvent of carbon disulfide and N-methyl-2-pyrrolidinone (CS2-NMP) was measured to study the network structure of the constituents. In experiment, Upper Freeport coal and Zao Zhuang coal were used as specimens. Viscoelasticity of various gels with different weight fractions of solvent was measured by creep measurement under a fixed load and stress-strain analysis under variable loads. In the 2nd and 3rd creep measurements, although no large changes in elastic strain and viscoelastic strain were found, viscous strain gradually decreased with an increase in viscosity. In the case of small weight fraction of solvent, small viscous strain and viscoelastic strain were found, while slightly large elastic strain was found. It was thus suggested that this elastic strain is derived from not only physical cross-linked networks by coal-solvent interaction but also those by coal-coal interaction in polymer chains of coal itself. 9 refs., 4 figs., 1 tab.

  5. Influence of high temperature processing of sol-gel derived barium titanate thin films deposited on platinum and strontium ruthenate coated silicon wafers

    NARCIS (Netherlands)

    Stawski, Tomasz; Vijselaar, Wouter Jan, Cornelis; Göbel, Ole; Veldhuis, Sjoerd; Smith, B.F.; Blank, David H.A.; ten Elshof, Johan E.

    2012-01-01

    Thin films of barium titanate (BTO) of 200 nm thickness, derived from an alkoxide¿carboxylate sol¿gel process, were deposited on Pt/Ti and SrRuO3/ZrO2¿8%Y2O3 coated Si wafers. Films with a dense columnar microstructure were obtained by repeated deposition of thin amorphous layers from

  6. Sol-Gel-Based Titania-Silica Thin Film Overlay for Long Period Fiber Grating-Based Biosensors.

    Science.gov (United States)

    Chiavaioli, Francesco; Biswas, Palas; Trono, Cosimo; Jana, Sunirmal; Bandyopadhyay, Somnath; Basumallick, Nandini; Giannetti, Ambra; Tombelli, Sara; Bera, Susanta; Mallick, Aparajita; Baldini, Francesco

    2015-12-15

    An evanescent wave optical fiber biosensor based on titania-silica-coated long period grating (LPG) is presented. The chemical overlay, which increases the refractive index (RI) sensitivity of the sensor, consists of a sol-gel-based titania-silica thin film, deposited along the sensing portion of the fiber by means of the dip-coating technique. Changing both the sol viscosity and the withdrawal speed during the dip-coating made it possible to adjust the thickness of the film overlay, which is a crucial parameter for the sensor performance. After the functionalization of the fiber surface using a methacrylic acid/methacrylate copolymer, an antibody/antigen (IgG/anti-IgG) assay was carried out to assess the performance of sol-gel based titania-silica-coated LPGs as biosensors. The analyte concentration was determined from the wavelength shift at the end of the binding process and from the initial binding rate. This is the first time that a sol-gel based titania-silica-coated LPG is proposed as an effective and feasible label-free biosensor. The specificity of the sensor was validated by performing the same model assay after spiking anti-IgG into human serum. With this structured LPG, detection limits of the order of tens of micrograms per liter (10(-11) M) are attained.

  7. Influence of annealing temperature and organic dyes as sensitizers on sol–gel derived TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Mamta; Abbas, Saeed J.; Tripathi, S.K., E-mail: surya@pu.ac.in

    2014-09-15

    Highlights: • Preparation of rice shaped TiO{sub 2} nanorods with anatase structure by sol–gel method. • Effect of post deposition annealing on structural properties of TiO{sub 2} is studied. • Unlike individual dye, absorption of Cocktail dye with TiO{sub 2} nanorods is broader. • Cocktail dye sensitized TiO{sub 2} film has more photosensitivity than EY, RB, AO. • Increase in photosensitivity up to optimum temperature is due to hole passivation. - Abstract: Five different organic dyes and reported cocktail dye composed of these dyes are used as sensitizer for titanium dioxide (TiO{sub 2}). Rice shaped (TiO{sub 2}) nanorods are prepared by using sol–gel method. The films annealed at 673 K and above are crystalline with anatase structure. The effect of post annealing temperature is studied on various structural parameters. Cocktail dye shows broader absorption with TiO{sub 2} nanorods in visible region compared with five dyes. Maximum photosensitivity is obtained with RhB dye, followed by FGF and cocktail dye sensitized TiO{sub 2} films. Increase in photosensitivity is due to passivating some hole traps on the surface up to some optimum temperature, above which photosensitivity decreases due to a higher photo activation energy compared to dark conductivity in low temperature region and also may be due to damage of the dye molecule. This work may prove its worth for understanding the electron transport in dye sensitized nanodevices.

  8. Nanostructured Mesoporous Titanium Dioxide Thin Film Prepared by Sol-Gel Method for Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Yu-Chang Liu

    2011-01-01

    Full Text Available Titanium dioxide (TiO2 paste was prepared by sol-gel and hydrothermal method with various precursors. Nanostructured mesoporous TiO2 thin-film back electrode was fabricated from the nanoparticle colloidal paste, and its performance was compared with that made of commercial P25 TiO2. The best performance was demonstrated by the DSSC having a 16 μm-thick TTIP-TiO2 back electrode, which gave a solar energy conversion efficiency of 6.03%. The ability of stong adhesion on ITO conducting glass substrate and the high surface area are considered important characteristics of TiO2 thin film. The results show that a thin film with good adhesion can be made from the prepared colloidal paste as a result of alleviating the possibility of electron transfer loss. One can control the colloidal particle size from sol-gel method. Therefore, by optimizing the preparation conditions, TiO2 paste with nanoparticle and narrow diameter distribution was obtained.

  9. Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

    Directory of Open Access Journals (Sweden)

    Abdel-Sattar Gadallah

    2013-01-01

    Full Text Available We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

  10. Growth and optical properties of sol-gel ZnO thin films grown on R-plane sapphire substrates

    Science.gov (United States)

    Nam, Giwoong; Kim, Min Su; Lee, Jewon; Leem, Jae-Young; Lee, Sang-heon; Jung, Jae Hak; Kim, Jin Soo; Kim, Jong Su

    2013-04-01

    Zinc-oxide (ZnO) thin films were grown on R-plane sapphire substrates by using the sol-gel spincoating method. They were annealed at temperatures ranging from 600 to 800 °C. The effects of the annealing temperature on the properties of the ZnO thin films were investigated using scanning electron microscopy, X-ray diffraction, and photoluminescence. When the annealing temperature was increased to 700 °C, the grains of the ZnO thin films coalesced, their size increased, and the residual stress in the ZnO thin films was relaxed. In addition, the intensity of the deep-level emission peak caused by defects decreased, and the full width at half maximum of the near-bandedge emission peak decreased as the annealing temperature was increased to 700 °C. However, when the annealing temperature was increased further, degradation of the structural and the optical properties was observed. The reflective index of the ZnO thin films in the UV region increased as the annealing temperature was increased to 700 °C, and n in the visible region decreased with increasing wavelength. The extinction coefficient in the UV and the visible regions decreased as the annealing temperature was increased to 700 °C. However, inflection points in the reflective index and the extinction coefficient were observed with a further increase in the annealing temperature.

  11. Optical and Electrical Characteristic of Layer-by-layer Sol-gel Spin Coated Nanoparticles ZnO Thin Films

    International Nuclear Information System (INIS)

    Shafinaz Sobihana Shariffudin; Farah Farliana Samat; Sukreen Hana; Mohamad Rusop

    2011-01-01

    Transparent ZnO thin films have been deposited on glass substrate using sol-gel spin coating technique. 0.35 M sol were prepared by dissolving zinc acetate dehydrate in 2-methoxyethanol with monoethanolamine as the stabilizer. In this paper, a novel method called layer-by-layer is introduced, where the thin film is not only dried after each layer is spin-coated, but also directly annealed at 500 degree Celsius to improve the crystallinity of the films. Samples without annealing were also prepared as the control sample. ZnO thin films were characterized using field emission scanning electron microscopy, X-ray diffraction, current-voltage measurement, UV-Vis spectroscopy and photoluminescence spectroscopy. The results revealed that layer by- layer ZnO thin films have better conductivity and higher intensity peak for PL spectra at visible spectra of 580 nm. FE-SEM images shows nanoparticles almost hexagonal shaped with high crystallinity compared to control samples. (author)

  12. Zirconium titanate thin film prepared by surface sol-gel process and effects of thickness on dielectric property

    CERN Document Server

    Kim, C H

    2002-01-01

    Single phase of multicomponent oxide ZrTiO sub 4 film could be prepared through surface sol-gel route simply by coating the mixture of 100mM zirconium butoxide and titanium butoxide on Pt/Ti/SiO sub 2 /Si(100) substrate, following pyrolysis at 450 .deg. C, and annealing it at 770 .deg. C. The dielectric constant of the film was reduced as the film thickness decreased due to of the interfacial effects caused by layer/electrode and a few voids inside the multilayer. However, the dielectric property was independent of applied dc bias sweeps voltage (-2 to +2 V). The dielectric constant of bulk film, 31.9, estimated using series-connected capacitor model was independent of film thickness and frequency in the measurement range, but theoretical interfacial thickness, t sub i , was dependent on the frequency. It reached a saturated t sub i value, 6.9 A, at high frequency by extraction of some capacitance component formed at low frequency range. The dielectric constant of bulk ZrTiO sub 4 pellet-shaped material was 3...

  13. Photoluminescence of nanocrystalline ZnS thin film grown by sol-gel method.

    Science.gov (United States)

    Anila, E I; Safeera, T A; Reshmi, R

    2015-03-01

    Nano and polycrystalline ZnS thin films play a crucial role in photovoltaic technology and optoelectronic devices. In this work, we report the photoluminescence (PL) characterization of nanocrystalline ZnS thin films synthesized by dip coating method. The PL spectra exhibit broad nature with multiple emission peaks which are due to the different defect levels in the prepared film.

  14. Highly sensitive determination of hydroxylamine using fused gold nanoparticles immobilized on sol-gel film modified gold electrode

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, P. [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Dindigul, Tamilnadu (India); John, S. Abraham, E-mail: abrajohn@yahoo.co.in [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Dindigul, Tamilnadu (India)

    2010-03-24

    We are reporting the highly sensitive determination of hydroxylamine (HA) using 2-mercapto-4-methyl-5-thiazoleacetic acid (TAA) capped fused spherical gold nanoparticles (AuNPs) modified Au electrode. The fused TAA-AuNPs were immobilized on (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel film, which was pre-assembled on Au electrode. The immobilization of fused TAA-AuNPs on MPTS sol-gel film was confirmed by UV-vis absorption spectroscopy and atomic force microscopy (AFM). The AFM image showed that the AuNPs retained the fused spherical morphology after immobilized on sol-gel film. The fused TAA-AuNPs on MPTS modified Au electrode were used for the determination of HA in phosphate buffer (PB) solution (pH = 7.2). When compared to bare Au electrode, the fused AuNPs modified electrode not only shifted the oxidation potential of HA towards less positive potential but also enhanced its oxidation peak current. Further, the oxidation of HA was highly stable at fused AuNPs modified electrode. Using amperometric method, determination of 17.5 nM HA was achieved for the first time. Further, the current response of HA increases linearly while increasing its concentration from 17.5 nM to 22 mM and a detection limit was found to be 0.39 nM (S/N = 3). The present modified electrode was also successfully used for the determination of 17.5 nM HA in the presence of 200-fold excess of common interferents such as urea, NO{sub 2}{sup -}, NH{sub 4}{sup +}, oxalate, Mn{sup 2+}, Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Ba{sup 2+} and Cu{sup 2+}. The practical application of the present modified electrode was demonstrated by measuring the concentration of HA in ground water samples.

  15. Highly sensitive determination of hydroxylamine using fused gold nanoparticles immobilized on sol-gel film modified gold electrode.

    Science.gov (United States)

    Kannan, P; John, S Abraham

    2010-03-24

    We are reporting the highly sensitive determination of hydroxylamine (HA) using 2-mercapto-4-methyl-5-thiazoleacetic acid (TAA) capped fused spherical gold nanoparticles (AuNPs) modified Au electrode. The fused TAA-AuNPs were immobilized on (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel film, which was pre-assembled on Au electrode. The immobilization of fused TAA-AuNPs on MPTS sol-gel film was confirmed by UV-vis absorption spectroscopy and atomic force microscopy (AFM). The AFM image showed that the AuNPs retained the fused spherical morphology after immobilized on sol-gel film. The fused TAA-AuNPs on MPTS modified Au electrode were used for the determination of HA in phosphate buffer (PB) solution (pH=7.2). When compared to bare Au electrode, the fused AuNPs modified electrode not only shifted the oxidation potential of HA towards less positive potential but also enhanced its oxidation peak current. Further, the oxidation of HA was highly stable at fused AuNPs modified electrode. Using amperometric method, determination of 17.5 nM HA was achieved for the first time. Further, the current response of HA increases linearly while increasing its concentration from 17.5 nM to 22 mM and a detection limit was found to be 0.39 nM (S/N=3). The present modified electrode was also successfully used for the determination of 17.5 nM HA in the presence of 200-fold excess of common interferents such as urea, NO(2)(-), NH(4)(+), oxalate, Mn(2+), Na(+), K(+), Mg(2+), Ca(2+), Ba(2+) and Cu(2+). The practical application of the present modified electrode was demonstrated by measuring the concentration of HA in ground water samples. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Nanoencapsulation of Rose-Hip Oil Prevents Oil Oxidation and Allows Obtainment of Gel and Film Topical Formulations.

    Science.gov (United States)

    Contri, Renata V; Kulkamp-Guerreiro, Irene C; da Silva, Sheila Janine; Frank, Luiza A; Pohlmann, Adriana R; Guterres, Silvia S

    2016-08-01

    The rose-hip oil holds skin regenerating properties with applications in the dermatological and cosmetic area. Its nanoencapsulation might favor the oil stability and its incorporation into hydrophilic formulations, besides increasing the contact with the skin and prolonging its effect. The aim of the present investigation was to develop suitable rose-hip-oil-loaded nanocapsules, to verify the nanocapsule effect on the UV-induced oxidation of the oil and to obtain topical formulations by the incorporation of the nanocapsules into chitosan gel and film. The rose-hip oil (500 or 600 μL), polymer (Eudragit RS100®, 100 or 200 mg), and acetone (50 or 100 mL) contents were separately varied aiming to obtain an adequate size distribution. The results led to a combination of the factors acetone and oil. The developed formulation showed average diameter of 158 ± 6 nm with low polydispersity, pH of 5.8 ± 0.9, zeta potential of +9.8 ± 1.5 mV, rose-hip oil content of 54 ± 1 μL/mL and tendency to reversible creaming. No differences were observed in the nanocapsules properties after storage. The nanoencapsulation of rose-hip oil decreased the UVA and UVC oxidation of the oil. The chitosan gel and film containing rose-hip-oil-loaded nanocapsules showed suitable properties for cutaneous use. In conclusion, it was possible to successfully obtain rose-hip-oil-loaded nanocapsules and to confirm the nanocapsules effect in protecting the oil from the UV rays. The chitosan gel and film were considered interesting alternatives for incorporating the nanoencapsulated rose-hip oil, combining the advantages of the nanoparticles to the advantages of chitosan.

  17. High-coercivity CoFe{sub 2}O{sub 4} thin films on Si substrates by sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xianwu; Jin, Linghua; Wei, Renhuai; Zhu, Xiaoguang; Yang, Jie; Dai, Jianming; Song, Wenhai [Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei 230031 (China); Zhu, Xuebin, E-mail: xbzhu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei 230031 (China); Hefei Science Center, CAS, Hefei 230031 (China); Sun, Yuping, E-mail: ypsun@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei 230031 (China); High Magnetic Field Laboratory, CAS, Hefei 230031 (China)

    2017-01-15

    CoFe{sub 2}O{sub 4} (CFO) thin films with high coercivity H{sub C} are desirable in applications. The difficulty in achieving large-area CFO thin films with high coercivity by sol-gel has hindered the development of CFO thin films. Herein, polycrystalline CFO thin films with the room temperature out-of-plane and in-plane coercivity H{sub C} respectively reached ~5.9 and 3.6 kOe has been achieved on the silicon substrate by sol-gel. The room-temperature maximum magnetic energy product (BH){sub max} and remanence ratio M{sub r}/M{sub s} are of 1.66 MG Oe and 0.58 respectively, which are also the largest values amongst the CFO thin films prepared by solution methods. At the same time, annealing temperature and thickness effects on the H{sub C}, (BH){sub max} and M{sub r}/M{sub s} of the derived CFO thin films have been investigated. It is observed that grain size and residual tensile strain in the derived films play an important role in the variations of H{sub C} and M{sub r}/M{sub s}. These results will provide an effective route for fabricating larger-area high-coercivity CFO thin films with low-cost by sol-gel on silicon wafers. - Highlights: • The CFO films show the largest room-temperature H{sub c} amongst the sol-gel derived ones. • (BH){sub max} and M{sub r}/M{sub s} are also the largest amongst the CFO films derived in this way. • Grain size and residual strain are the key to the improved films magnetic properties.

  18. The zinc-loss effect and mobility enhancement of DUV-patterned sol–gel IGZO thin-film transistors

    Science.gov (United States)

    Wang, Kuan-Hsun; Zan, Hsiao-Wen; Soppera, Olivier

    2018-03-01

    We investigate the composition of the DUV-patterned sol–gel indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) and observe a significant zinc loss effect during developing when the DUV exposure is insufficient. The zinc loss, however, is beneficial for increasing the mobility. Reducing zinc to indium composition ratio from 0.5 to 0.02 can effectively increase mobility from 0.27 to 7.30 cm2 V–1 s–1 when the gallium to indium ratio is fixed as 0.25 and the post annealing process is fixed as 300 °C for 2 h. On the other hand, an IGO TFT fails to deliver a uniform film and a reproducible TFT performance, revealing the critical role of zinc in forming homogeneous IGZO TFTs.

  19. Evaluation of bulk and surfaces absorption edge energy of sol-gel-dip-coating SnO2 thin films

    Directory of Open Access Journals (Sweden)

    Emerson Aparecido Floriano

    2010-12-01

    Full Text Available The absorption edge and the bandgap transition of sol-gel-dip-coating SnO2 thin films, deposited on quartz substrates, are evaluated from optical absorption data and temperature dependent photoconductivity spectra. Structural properties of these films help the interpretation of bandgap transition nature, since the obtained nanosized dimensions of crystallites are determinant on dominant growth direction and, thus, absorption energy. Electronic properties of the bulk and (110 and (101 surfaces are also presented, calculated by means of density functional theory applied to periodic calculations at B3LYP hybrid functional level. Experimentally obtained absorption edge is compared to the calculated energy band diagrams of bulk and (110 and (101 surfaces. The overall calculated electronic properties in conjunction with structural and electro-optical experimental data suggest that the nature of the bandgap transition is related to a combined effect of bulk and (101 surface, which presents direct bandgap transition.

  20. Effect of sol concentration on the properties of ZnO thin films prepared by sol-gel technique

    International Nuclear Information System (INIS)

    Dutta, M.; Mridha, S.; Basak, D.

    2008-01-01

    ZnO thin films are deposited on the glass substrates by sol-gel drain coating technique by varying the concentration of the sol. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used to investigate the effect of sol concentration on the crystallinity and surface morphology of the films. The results show that with increase in sol concentration, the value of full width at half maximum (FWHM) of (0 0 2) peak decreases while the strain first increases and then decreases. The sol with higher concentration results in the increase in the grain size. The studies on the optical properties show that the band gap value increases from 3.27 to 3.3 eV when the sol concentration changes from 0.03 to 0.1 M. The photoconductivity studies reveal that the film for 0.05 M sol shows the maximum photoresponse for ultraviolet (UV) wavelength (<400 nm) which is co-related with the deep-level defects. The growth and decay of the photocurrent is found to be slowest for the same film

  1. Microwave-assisted nonaqueous sol-gel deposition of different spinel ferrites and barium titanate perovskite thin films.

    Science.gov (United States)

    Kubli, Martin; Luo, Li; Bilecka, Idalia; Niederberger, Markus

    2010-01-01

    Rapid and selective heating of solvents by microwave irradiation coupled to nonaqueous sol-gel chemistry makes it possible to simultaneously synthesize metal oxide nanoparticles within minutes and deposit them on substrates. The simple immersion of substrates, such as glass slides, in the reaction solution results after microwave heating in the deposition of homogeneous porous thin films whose thickness can be adjusted through the precursor concentration. Here we use such a microwave-assisted nonaqueous sol-gel process for the formation of various spinel ferrite MFe2O4 (M = Fe, Co, Mn, Ni) and BaTiO3 nanoparticles and their deposition as thin films. The approach offers high flexibility with respect to controlling the crystal size by adjusting the reaction time and/or temperature. Based on the example of CoFe2O4 nanoparticles, we show how the crystal size can carefully be tuned from 4 to 8 nm, resulting in a continuous change of the magnetic properties.

  2. A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

    Directory of Open Access Journals (Sweden)

    Hairong Wang

    2014-09-01

    Full Text Available An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor’s output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10−4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

  3. Sol-gel TiO2 colloidal suspensions and nanostructured thin films: structural and biological assessments

    Science.gov (United States)

    Quartapelle Procopio, Elsa; Colombo, Valentina; Santo, Nadia; Sironi, Angelo; Lenardi, Cristina; Maggioni, Daniela

    2018-02-01

    The role of substrate topography in phenotype expression of in vitro cultured cells has been widely assessed. However, the production of the nanostructured interface via the deposition of sol-gel synthesized nanoparticles (NPs) has not yet been fully exploited. This is also evidenced by the limited number of studies correlating the morphological, structural and chemical properties of the grown thin films with those of the sol-gel ‘brick’ within the framework of the bottom-up approach. Our work intends to go beyond this drawback presenting an accurate investigation of sol-gel TiO2 NPs shaped as spheres and rods. They have been fully characterized by complementary analytical techniques both suspended in apolar solvents, by dynamic light scattering (DLS) and nuclear magnetic resonance (NMR) and after deposition on substrates (solid state configuration) by transmission electron microscopy (TEM) and powder x-ray diffraction (PXRD). In the case of suspended anisotropic rods, the experimental DLS data, analyzed by the Tirado-Garcia de la Torre model, present the following ranges of dimensions: 4-5 nm diameter (∅) and 11-15 nm length (L). These results are in good agreement with that obtained by the two solid state techniques, namely 3.8(9) nm ∅ and 13.8(2.5) nm L from TEM and 5.6(1) ∅ and 13.3(1) nm L from PXRD data. To prove the suitability of the supported sol-gel NPs for biological issues, spheres and rods have been separately deposited on coverslips. The cell response has been ascertained by evaluating the adhesion of the epithelial cell line Madin-Darby canine kidney. The cellular analysis showed that titania films promote cell adhesion as well clustering organization, which is a distinguishing feature of this type of cell line. Thus, the use of nanostructured substrates via sol-gel could be considered a good candidate for cell culture with the further advantages of likely scalability and interfaceability with many different materials usable as supports.

  4. Sol-gel TiO2 colloidal suspensions and nanostructured thin films: structural and biological assessments.

    Science.gov (United States)

    Procopio, Elsa Quartapelle; Colombo, Valentina; Santo, Nadia; Sironi, Angelo; Lenardi, Cristina; Maggioni, Daniela

    2018-02-02

    The role of substrate topography in phenotype expression of in vitro cultured cells has been widely assessed. However, the production of the nanostructured interface via the deposition of sol-gel synthesized nanoparticles (NPs) has not yet been fully exploited. This is also evidenced by the limited number of studies correlating the morphological, structural and chemical properties of the grown thin films with those of the sol-gel 'brick' within the framework of the bottom-up approach. Our work intends to go beyond this drawback presenting an accurate investigation of sol-gel TiO 2 NPs shaped as spheres and rods. They have been fully characterized by complementary analytical techniques both suspended in apolar solvents, by dynamic light scattering (DLS) and nuclear magnetic resonance (NMR) and after deposition on substrates (solid state configuration) by transmission electron microscopy (TEM) and powder x-ray diffraction (PXRD). In the case of suspended anisotropic rods, the experimental DLS data, analyzed by the Tirado-Garcia de la Torre model, present the following ranges of dimensions: 4-5 nm diameter (∅) and 11-15 nm length (L). These results are in good agreement with that obtained by the two solid state techniques, namely 3.8(9) nm ∅ and 13.8(2.5) nm L from TEM and 5.6(1) ∅ and 13.3(1) nm L from PXRD data. To prove the suitability of the supported sol-gel NPs for biological issues, spheres and rods have been separately deposited on coverslips. The cell response has been ascertained by evaluating the adhesion of the epithelial cell line Madin-Darby canine kidney. The cellular analysis showed that titania films promote cell adhesion as well clustering organization, which is a distinguishing feature of this type of cell line. Thus, the use of nanostructured substrates via sol-gel could be considered a good candidate for cell culture with the further advantages of likely scalability and interfaceability with many different materials usable as supports.

  5. The effect of dopants on the morphology, microstructure and electrical properties of transparent zinc oxide films prepared by the sol-gel method

    International Nuclear Information System (INIS)

    O'Brien, Shane; Çopuroglu, Mehmet; Tassie, Paul; Nolan, Mark G.; Hamilton, Jeff A.; Povey, Ian; Pereira, Luis; Martins, Rodrigo; Fortunato, Elvira; Pemble, Martyn E.

    2011-01-01

    The influence of doping on the morphology, physical and electrical properties of zinc oxide produced by the sol-gel method was examined. Undoped zinc oxide was observed to form relatively porous films. Addition of an Al dopant influenced the sheet resistance, but did not result in a change in morphology, examined by atomic force microscopy when compared to undoped films. In the case of electrical measurements, undoped ZnO films were extremely resistive. A minimum dopant concentration of 2 at.%. Al was required to produce materials which were more conductive, as observed by sheet resistance measurements, which were shown to vary with annealing temperature. The versatile nature of sol-gel processing was demonstrated by selective ink-jet deposition of sol-gel droplets which were annealed to form oxide materials.

  6. SnO2 thin-films prepared by a spray-gel pyrolysis: Influence of sol properties on film morphologies

    International Nuclear Information System (INIS)

    Luyo, Clemente; Fabregas, Ismael; Reyes, L.; Solis, Jose L.; Rodriguez, Juan; Estrada, Walter; Candal, Roberto J.

    2007-01-01

    Nanostructured tin oxide films were prepared by depositing different sols using the so-called spray-gel pyrolysis process. SnO 2 suspensions (sols) were obtained from tin (IV) tert-amyloxide (Sn(t-OAm) 4 ) or tin (IV) chloride pentahydrate (SnCl 4 .5H 2 O) precursors, and stabilized with ammonia or tetraethylammonium hydroxide (TEA-OH). Xerogels from the different sols were obtained by solvent evaporation under controlled humidity. The Relative Gelling Volumes (RGV) of these sols strongly depended on the type of precursor. Xerogels obtained from inorganic salts gelled faster, while, as determined by thermal gravimetric analysis, occluding a significant amount of volatile compounds. Infrared spectroscopic analysis was performed on raw and annealed xerogels (300, 500 deg. C, 1 h). Annealing removed water and ammonium or alkyl ammonium chloride, increasing the number of Sn-O-Sn bonds. SnO 2 films were prepared by spraying the sols for 60 min onto glass and alumina substrates at 130 deg. C. The films obtained from all the sols were amorphous or displayed a very small grain size, and crystallized after annealing at 400 deg. C or 500 deg. C in air for 2 h. X-ray diffraction analysis showed the presence of the cassiterite structure and line broadening indicated a polycrystalline material with a grain size in the nanometer range. Results obtained from Scanning Electron Microscopy analysis demonstrated a strong dependence of the film morphology on the RGV of the sols. Films obtained from Sn(t-OAm) 4 showed a highly textured morphology based on fiber-shape bridges, whereas the films obtained from SnCl 4 .5H 2 O had a smoother surface formed by 'O-ring' shaped domains. Lastly, the performance of these films as gas sensor devices was tested. The conductance (sensor) response for ethanol as a target analyte was of the same order of magnitude for the three kinds of films. However, the response of the highly textured films was more stable with shorter response times

  7. Effect of metal ion dopants on photochemical properties of anatase TiO{sub 2} films synthesized by a modified sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Zhangfu [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)]. E-mail: yuanzhf@home.ipe.ac.cn; Zhang Junling [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Bin [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Jianqiang [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)

    2007-06-25

    Anatase TiO{sub 2} films were successfully synthesized by a modified sol-gel method wherein peroxo titanic acid solution was derived from TiCl{sub 4}/ethanol/water solution at room temperature. The as-prepared films were further surface-doped by photodeposited Fe{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} to improve its physicochemical properties. The phase and structure of the films were investigated by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The physicochemical properties of the films were also measured. The results show that both hydrophilicity and photocatalytic activity of the films were remarkably improved by doping transition metal ion Fe{sup 3+}. In case of Cr{sup 3+} doped films, hydrophilicity was also significantly enhanced but photocatalytic activity for methyl orange under UV irradiation was still comparable with the undoped films.

  8. Multiferroic properties of a YCrO3/BiFeO3 bilayered thin film prepared by a sol-gel method

    Science.gov (United States)

    Kuang, Daihong; Yang, Fangyuan; Jing, Weiwen; Yang, Zhanjin

    2018-02-01

    YCrO3 (YCO), BiFeO3 (BFO), and YCrO3/BiFeO3 (YCO-BFO) thin films were prepared on quartz substrates using spin coating by a sol-gel method. X-ray diffraction demonstrated that YCO and BFO thin films had a perovskite orthorhombic, and rhombohedral structure, respectively. The stronger and sharper diffraction intensity of YCO-BFO bilayered thin film indicated that the bottom YCO layer was able to promote the grain growth of BFO film, which was further verified by scanning electron microscope. The ferroelectric test demonstrated that the leakage current density of YCO-BFO bilayered film was reduced by one order of magnitude compared to that of BFO film, which had a better ferroelectric property. Optical absorption spectra indicated that the band gap of YCO-BFO thin film was lower than that of BFO film, suggesting their potential application as UV and blue-green-driven photocatalysts. The magnetic test verified that the ferromagnetic property of YCO-BFO film was obviously enhanced compared to those of BFO and YCO thin films. The results revealed that YCO layer played an important role for improving multiferroic properties of BFO thin film. The mechanisms of the effects of bottom YCO layer on optical and multiferroic properties of BFO thin film in the YCO-BFO bilayered film were discussed in detail.

  9. Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    Fatemeh Zabihi

    2017-05-01

    Full Text Available In this work, we communicate a facile and low temperature synthesis process for the fabrication of graphene-TiO2 photocatalytic composite thin films. A sol-gel chemical route is used to synthesize TiO2 from the precursor solutions and spin and spray coating are used to deposit the films. Excitation of the wet films during the casting process by ultrasonic vibration favorably influences both the sol-gel route and the deposition process, through the following mechanisms. The ultrasound energy imparted to the wet film breaks down the physical bonds of the gel phase. As a result, only a low-temperature post annealing process is required to eliminate the residues to complete the conversion of precursors to TiO2. In addition, ultrasonic vibration creates a nanoscale agitating motion or microstreaming in the liquid film that facilitates mixing of TiO2 and graphene nanosheets. The films made based on the above-mentioned ultrasonic vibration-assisted method and annealed at 150 °C contain both rutile and anatase phases of TiO2, which is the most favorable configuration for photocatalytic applications. The photoinduced and photocatalytic experiments demonstrate effective photocurrent generation and elimination of pollutants by graphene-TiO2 composite thin films fabricated via scalable spray coating and mild temperature processing, the results of which are comparable with those made using lab-scale and energy-intensive processes.

  10. Fabrication and properties of zinc oxide thin film prepared by sol-gel dip coating method

    Directory of Open Access Journals (Sweden)

    Kayani Zohra Nazir

    2015-09-01

    Full Text Available ZnO thin films were deposited on a glass substrate by dip coating technique using a solution of zinc acetate, ethanol and distilled water. Optical constants, such as refractive index n and extinction coefficient k. were determined from transmittance spectrum in the ultraviolet-visible-near infrared (UV-Vis-NIR regions using envelope methods. The films were found to exhibit high transmittance, low absorbance and low reflectance in the visible regions. Absorption coefficient α and the thickness of the film t were calculated from interference of transmittance spectra. The direct optical band gap of the films was in the range of 3.98 to 3.54 eV and the thickness of the films was evaluated in the range of 173 to 323 nm, while the refractive index slightly varied in the range of 1.515 to 1.622 with an increase in withdrawal speed from 100 to 250 mm/s. The crystallographic structure of the films was analyzed with X-ray diffractometer. The films were amorphous in nature.

  11. Epoxy-based organic-inorganic nanocomposite coatings and films prepared by sol-gel process

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Brus, Jiří; Matějka, Libor

    2004-01-01

    Roč. 6, 3-4 (2004), s. 7-15 R&D Projects: GA ČR GA203/01/0735; GA AV ČR IAA4050008; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : sol-gel process * nanocomposites * solid-state NMR Subject RIV: CD - Macromolecular Chemistry

  12. An alternative sol-gel route for the preparation of thin films in CeO2-TiO2 binary system

    International Nuclear Information System (INIS)

    Kidchob, Tongjit; Malfatti, Luca; Marongiu, Daniela; Enzo, Stefano; Innocenzi, Plinio

    2010-01-01

    Thin films of titania-ceria have been prepared via sol-gel processing by employing titanium and cerium chloride compounds in highly acidic conditions for the precursor sol. This sol-gel route allows obtaining titania-ceria and cerium titanate films, CeTi 2 O 6 , after thermal treatment in air. The films exhibit a high optical transparency which is modulated by controlling the composition and the thermal treatment. The materials have been characterized by X-ray diffraction, UV-visible spectroscopy, ellipsometric spectroscopy and atomic force microscopy. The titania-ceria films show, as a function of the composition, the formation of different phases after thermal treatment in air at 800 o C. In particular, with the composition Ce25-Ti75 we have obtained a pure cerium titanate phase, CeTi 2 O 6 , which can be formed only in a very strict range of compositions.

  13. An alternative sol-gel route for the preparation of thin films in CeO{sub 2}-TiO{sub 2} binary system

    Energy Technology Data Exchange (ETDEWEB)

    Kidchob, Tongjit; Malfatti, Luca; Marongiu, Daniela [Laboratorio di Scienza dei Materiali e Nanotecnologie, D.A.P., Universita di Sassari and CR-INSTM, Palazzo Pou Salid, Piazza Duomo 6, 07041 Alghero (Italy); Enzo, Stefano [Dipartimento di Chimica, Universita di Sassari, Via Vienna 2, 07100 Sassari (Italy); Innocenzi, Plinio, E-mail: plinio@uniss.i [Laboratorio di Scienza dei Materiali e Nanotecnologie, D.A.P., Universita di Sassari and CR-INSTM, Palazzo Pou Salid, Piazza Duomo 6, 07041 Alghero (Italy)

    2010-01-01

    Thin films of titania-ceria have been prepared via sol-gel processing by employing titanium and cerium chloride compounds in highly acidic conditions for the precursor sol. This sol-gel route allows obtaining titania-ceria and cerium titanate films, CeTi{sub 2}O{sub 6}, after thermal treatment in air. The films exhibit a high optical transparency which is modulated by controlling the composition and the thermal treatment. The materials have been characterized by X-ray diffraction, UV-visible spectroscopy, ellipsometric spectroscopy and atomic force microscopy. The titania-ceria films show, as a function of the composition, the formation of different phases after thermal treatment in air at 800 {sup o}C. In particular, with the composition Ce25-Ti75 we have obtained a pure cerium titanate phase, CeTi{sub 2}O{sub 6}, which can be formed only in a very strict range of compositions.

  14. Hydrogen sensing by sol–gel grown NiO and NiO:Li thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sta, I., E-mail: imenstalpv@yahoo.fr [Photovoltaic Laboratory, Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia); Jlassi, M. [Photovoltaic Laboratory, Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia); Kandyla, M. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vasileos Konstantinou Ave., 11635 Athens (Greece); Hajji, M. [Photovoltaic Laboratory, Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia); National School of Electronics and Telecommunications of Sfax, Sfax Technopark, BP 1163, CP 3018 Sfax (Tunisia); Koralli, P. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vasileos Konstantinou Ave., 11635 Athens (Greece); Allagui, R. [Photovoltaic Laboratory, Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia); Kompitsas, M. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vasileos Konstantinou Ave., 11635 Athens (Greece); Ezzaouia, H. [Photovoltaic Laboratory, Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia)

    2015-03-25

    Highlights: • NiO:Li sensors were able to detect 1000 ppm hydrogen concentration in air. • The operation temperature was as low as 140 °C. • Performance of sensors was significantly improved by Li doping. - Abstract: Hydrogen sensors have been prepared using nickel oxide (NiO) and lithium-doped nickel oxide (NiO:Li) thin films, deposited on glass substrates by the sol–gel spin coating technique. The surface morphology, structure, optical and electrical properties of the obtained films were studied. Hydrogen sensing results are presented for three operating temperatures (140, 160, and 180 °C) and for hydrogen concentrations ranging from 1000 to 15,000 ppm in synthetic air. The NiO and NiO:Li (2% and 8% doping concentrations) sensors show maximum responses for the operating temperature of 180 °C. When tested at different hydrogen concentrations in air, the lithium-doped NiO sensors showed a higher response than the undoped NiO films.

  15. Hydrogen sensing by sol–gel grown NiO and NiO:Li thin films

    International Nuclear Information System (INIS)

    Sta, I.; Jlassi, M.; Kandyla, M.; Hajji, M.; Koralli, P.; Allagui, R.; Kompitsas, M.; Ezzaouia, H.

    2015-01-01

    Highlights: • NiO:Li sensors were able to detect 1000 ppm hydrogen concentration in air. • The operation temperature was as low as 140 °C. • Performance of sensors was significantly improved by Li doping. - Abstract: Hydrogen sensors have been prepared using nickel oxide (NiO) and lithium-doped nickel oxide (NiO:Li) thin films, deposited on glass substrates by the sol–gel spin coating technique. The surface morphology, structure, optical and electrical properties of the obtained films were studied. Hydrogen sensing results are presented for three operating temperatures (140, 160, and 180 °C) and for hydrogen concentrations ranging from 1000 to 15,000 ppm in synthetic air. The NiO and NiO:Li (2% and 8% doping concentrations) sensors show maximum responses for the operating temperature of 180 °C. When tested at different hydrogen concentrations in air, the lithium-doped NiO sensors showed a higher response than the undoped NiO films

  16. Enhanced photoelectrochemical performance of Ti-doped hematite thin films prepared by the sol-gel method

    Science.gov (United States)

    Lian, Xiaojuan; Yang, Xin; Liu, Shangjun; Xu, Ying; Jiang, Chunping; Chen, Jinwei; Wang, Ruilin

    2012-01-01

    Ti-doped α-Fe2O3 thin films were successfully prepared on FTO substrates by the sol-gel route. Hematite film was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The XRD data showed α-Fe2O3 had a preferred (1 1 0) orientation which belonged to the rhombohedral system. Interestingly, the grains turned into worm-like shape after annealed at high temperature. The IPCE could reach 32.6% at 400 nm without any additional potential vs. SCE. Titanium in the lattice can affect the photo electro chemical performance positively by increasing the conductivity of the thin film. So the excited electrons and holes could live longer, rather than recombining with each other rapidly as undoped hematite. And the efficient carrier density on the Ti-doped anode surface was higher than the undoped anode, which contribute to the well PEC performance.

  17. Carrier Density Modulation over an Exceptional Voltage Window in BaSnO3 Films via Ion Gel Gating

    Science.gov (United States)

    Wang, Helin; Walter, Jeff; Ganguly, Koustav; Prakash, Abhinav; Jalan, Bharat; Leighton, Chris

    BaSnO3 has drawn interest recently due to its outstanding room temperature mobility and potential applications in oxide transistors, transparent conductors, etc. Here we report effective control of the electronic transport properties of sputtered oxygen-vacancy-doped BaSnO3 (BaSnO3-δ) films via ion gel gating in electric double layer transistor structures. The electron densities of the starting films is tuned by thickness, from 4 × 1019 cm-3 at 13 nm to much lower densities at lower thickness. The response to gate voltage is found to be notably robust, with largely reversible response (even in vacuum) over an exceptionally wide window from -4 to +4 V, even at 300 K. The data support predominantly electrostatic response, unlike many other oxides, which we ascribe to Sn redox stability. In this manner the sheet resistance of 13-nm-thick BaSnO3 films can be modulated by a factor of 50 at 300 K, increasing to almost 103 at low temperatures. Similar measurements at lower thickness/electron density will also be discussed. Work supported by the NSF MRSEC under DMR-1420013.

  18. The importance of the methanol content in the precursor solution, on the physical properties of cadmium oxide thin films prepared by the sol-gel method

    International Nuclear Information System (INIS)

    Martinez Ayala, A.; Torres Delgado, G.; Castanedo Perez, R.; Zelaya Angel, O.

    2010-01-01

    Research highlights: → This work is important due to the recent interest for obtaining CdO films by simple and economical techniques. The sol-gel technique shows these characteristics. However, CdO films with higher thicknesses could be obtained starting from a high number of coats. In this work, the importance of the methanol content in the precursor solution on the physical properties of cadmium oxide thin films prepared by the sol-gel method was studied. For the first time, higher thicknesses of CdO films were obtained with a lower number of coats, changing the methanol content in the precursor solution. The films show good electrical, optical, structural properties for their use as transparent conductive films in solar cells. - Abstract: Undoped and fluorine doped cadmium oxide films were obtained by the sol-gel technique, starting from a simple precursor solution constituted of: cadmium acetate, methanol, glycerol and triethylamine and only for doped samples, ammonium fluoride as the fluoride source. Due to the methanol content used is higher with respect to the other reagents, variations in this parameter affect the viscosity and gelation time of the precursor solution, giving as result changes in the thickness. The importance of the methanol content in the growing solution on the structural, morphological, optical and electrical properties of the films is reported. Higher thickness was obtained for lower methanol content, in the range 33-46 mol, in the growing solution. Largest growing rate was obtained when the methanol content in the precursor solution was 33 mol. The films showed good characteristics for their use as transparent conductive films in solar cells.

  19. Characterizations of Cuprous Oxide Thin Films Prepared by Sol-Gel Spin Coating Technique with Different Additives for the Photoelectrochemical Solar Cell

    Directory of Open Access Journals (Sweden)

    D. S. C. Halin

    2014-01-01

    Full Text Available Cuprous oxide (Cu2O thin films were deposited onto indium tin oxide (ITO coated glass substrate by sol-gel spin coating technique using different additives, namely, polyethylene glycol and ethylene glycol. It was found that the organic additives added had a significant influence on the formation of Cu2O films and lead to different microstructures and optical properties. The films were characterized by X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, and ultraviolet-visible spectroscopy (UV-Vis. Based on the FESEM micrographs, the grain size of film prepared using polyethylene glycol additive has smaller grains of about 83 nm with irregular shapes. The highest optical absorbance film was obtained by the addition of polyethylene glycol. The Cu2O thin films were used as a working electrode in the application of photoelectrochemical solar cell (PESC.

  20. Cu-Doped ZnO Thin Films Deposited by a Sol-Gel Process Using Two Copper Precursors: Gas-Sensing Performance in a Propane Atmosphere

    Directory of Open Access Journals (Sweden)

    Heberto Gómez-Pozos

    2016-01-01

    Full Text Available A study on the propane gas-sensing properties of Cu-doped ZnO thin films is presented in this work. The films were deposited on glass substrates by sol-gel and dip coating methods, using zinc acetate as a zinc precursor, copper acetate and copper chloride as precursors for doping. For higher sensitivity values, two film thickness values are controlled by the six and eight dippings, whereas for doping, three dippings were used, irrespective of the Cu precursor. The film structure was analyzed by X-ray diffractometry, and the analysis of the surface morphology and film composition was made through scanning electron microscopy (SEM and secondary ion mass spectroscopy (SIMS, respectively. The sensing properties of Cu-doped ZnO thin films were then characterized in a propane atmosphere, C3H8, at different concentration levels and different operation temperatures of 100, 200 and 300 °C. Cu-doped ZnO films doped with copper chloride presented the highest sensitivity of approximately 6 × 104, confirming a strong dependence on the dopant precursor type. The results obtained in this work show that the use of Cu as a dopant in ZnO films processed by sol-gel produces excellent catalysts for sensing C3H8 gas.

  1. Quartz Crystal Microbalance Coated with Sol-gel-derived Thin Films as Gas Sensor for NO Detection

    Directory of Open Access Journals (Sweden)

    S. J. O’Shea

    2003-10-01

    Full Text Available This paper presents the possibilities and properties of Indium tin oxide (ITO-covered quartz crystal as a NOx toxic gas-sensor. The starting sol-gel solution was prepared by mixing indium chloride dissolved in acetylacetone and tin chloride dissolved in ethanol (0-20% by weight. The ITO thin films were deposited on the gold electrodes of quartz crystal by spin-coating technique and subsequently followed a standard photolithography to pattern the derived films to ensure all sensors with the same sensing areas. All heat treatment processes were controlled below 500°C in order to avoid the piezoelectric characteristics degradation of quartz crystal (Quartz will lose its piezoelectricity at ~573°C due to the phase change from α to β. The electrical and structural properties of ITO thin films were characterized with Hall analysis system, TG/DTA, XRD, XPS, SEM and etc. The gas sensor had featured with ITO thin films of ~100nm as the receptor to sense the toxic gas NO and quartz crystal with frequency of 10MHz as the transducer to transfer the surface reactions (mass loading, etc into the frequency shift. A homemade setup had been employed to measure the sensor response under the static mode. The experimental results had indicated that the ITO-coated QCM had a good sensitivity for NO gas, ~12Hz/100ppm within 5mins. These results prove that the ITO-covered quartz crystals are usable as a gas sensor and as an analytical device.

  2. Nanoscale morphology for high hydrophobicity of a hard sol-gel thin film

    International Nuclear Information System (INIS)

    Wu, Y.L.; Chen, Z.; Zeng, X.T.

    2008-01-01

    It is challenging to obtain a hydrophobic smooth coating with high optical and mechanical properties at the same time because the hydrophobic additives are soft in nature resulting in reduced hardness and durability. This paper reports a durable hydrophobic transparent coating on glass fabricated by sol-gel technology and a low volume medium pressure (LVMP) spray process. The sol-gel formula consists of a pre-linked hydrophobic nano-cluster from hydroxyl-terminated polydimethylsiloxane, titanium tetraisopropoxide and a silica-based sol-gel matrix with silica hard fillers. Polydimethylsiloxane (PDMS) is uniformly distributed throughout the coating layer providing durable hydrophobic property. Mechanical properties are achieved by the hard matrix and hard fillers with the nano-structures. Due to the surface nano-morphology, a high degree of hydrophobicity was maintained with only 10 vol.% PDMS, while the hardness and abrasion resistance of the coatings were not significantly compromised. Chemical analyses by FTIR confirmed the uniform distribution of the PDMS and surface morphology analyses by atomic force microscopy (AFM) displayed the nano-surface structures that enhanced the hydrophobicity. The special surface nanostructures can be quantified using surface Kurtosis and ratio between asperity peak height to distance between peaks. The LVMP process influences the spray droplet size resulting in different surface structures

  3. Nanoscale morphology for high hydrophobicity of a hard sol-gel thin film

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.L. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)], E-mail: ylwu@simtech.a-star.edu.sg; Chen, Z. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Zeng, X.T. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

    2008-08-30

    It is challenging to obtain a hydrophobic smooth coating with high optical and mechanical properties at the same time because the hydrophobic additives are soft in nature resulting in reduced hardness and durability. This paper reports a durable hydrophobic transparent coating on glass fabricated by sol-gel technology and a low volume medium pressure (LVMP) spray process. The sol-gel formula consists of a pre-linked hydrophobic nano-cluster from hydroxyl-terminated polydimethylsiloxane, titanium tetraisopropoxide and a silica-based sol-gel matrix with silica hard fillers. Polydimethylsiloxane (PDMS) is uniformly distributed throughout the coating layer providing durable hydrophobic property. Mechanical properties are achieved by the hard matrix and hard fillers with the nano-structures. Due to the surface nano-morphology, a high degree of hydrophobicity was maintained with only 10 vol.% PDMS, while the hardness and abrasion resistance of the coatings were not significantly compromised. Chemical analyses by FTIR confirmed the uniform distribution of the PDMS and surface morphology analyses by atomic force microscopy (AFM) displayed the nano-surface structures that enhanced the hydrophobicity. The special surface nanostructures can be quantified using surface Kurtosis and ratio between asperity peak height to distance between peaks. The LVMP process influences the spray droplet size resulting in different surface structures.

  4. Sol–Gel-Derived Glass-Ceramic Photorefractive Films for Photonic Structures

    Directory of Open Access Journals (Sweden)

    Anna Lukowiak

    2017-02-01

    Full Text Available Glass photonics are widespread, from everyday objects around us to high-tech specialized devices. Among different technologies, sol–gel synthesis allows for nanoscale materials engineering by exploiting its unique structures, such as transparent glass-ceramics, to tailor optical and electromagnetic properties and to boost photon-management yield. Here, we briefly discuss the state of the technology and show that the choice of the sol–gel as a synthesis method brings the advantage of process versatility regarding materials composition and ease of implementation. In this context, we present tin-dioxide–silica (SnO2–SiO2 glass-ceramic waveguides activated by europium ions (Eu3+. The focus is on the photorefractive properties of this system because its photoluminescence properties have already been discussed in the papers presented in the bibliography. The main findings include the high photosensitivity of sol–gel 25SnO2:75SiO2 glass-ceramic waveguides; the ultraviolet (UV-induced refractive index change (Δn ~ −1.6 × 10−3, the easy fabrication process, and the low propagation losses (0.5 ± 0.2 dB/cm, that make this glass-ceramic an interesting photonic material for smart optical applications.

  5. Effects of Ambient Air and Temperature on Ionic Gel Gated Single-Walled Carbon Nanotube Thin-Film Transistor and Circuits.

    Science.gov (United States)

    Li, Huaping; Zhou, Lili

    2015-10-21

    Single-walled carbon nanotube thin-film transistor (SWCNT TFT) and circuits were fabricated by fully inkjet printing gold nanoparticles as source/drain electrodes, semiconducting SWCNT thin films as channel materials, PS-PMMA-PS/EMIM TFSI composite gel as gate dielectrics, and PEDOT/PSS as gate electrodes. The ionic gel gated SWCNT TFT shows reversible conversion from p-type transistor behavior in air to ambipolar features under vacuum due to reversible oxygen doping in semiconducting SWCNT thin films. The threshold voltages of ionic gel gated SWCNT TFT and inverters are largely shifted to the low value (0.5 V for p-region and 1.0 V for n-region) by vacuum annealing at 140 °C to exhausively remove water that is incorporated in the ionic gel as floating gates. The vacuum annealed ionic gel gated SWCNT TFT shows linear temperature dependent transconductances and threshold voltages for both p- and n-regions. The strong temperature dependent transconductances (0.08 μS/K for p-region, 0.4 μS/K for n-region) indicate their potential application in thermal sensors. In the other hand, the weak temperature dependent threshold voltages (-1.5 mV/K for p-region, -1.1 mV/K for n-region) reflect their excellent thermal stability.

  6. Effect of iron doping on structural and optical properties of TiO2 thin film by sol–gel routed spin coating technique

    Directory of Open Access Journals (Sweden)

    Stephen Lourduraj

    2017-08-01

    Full Text Available Thin films of iron (Fe-doped titanium dioxide (Fe:TiO2 were prepared by sol–gel spin coating technique and further calcined at 450∘C. The structural and optical properties of Fe-doped TiO2 thin films were investigated by X-ray diffraction (XRD, scanning electron microscopy (SEM, ultraviolet–visible spectroscopy (UV–vis and atomic force microscopic (AFM techniques. The XRD results confirm the nanostructured TiO2 thin films having crystalline nature with anatase phase. The characterization results show that the calcined thin films having high crystallinity and the effect of iron substitution lead to decreased crystallinity. The SEM investigations of Fe-doped TiO2 films also gave evidence that the films were continuous spherical shaped particles with a nanometric range of grain size and film was porous in nature. AFM analysis establishes that the uniformity of the TiO2 thin film with average roughness values. The optical measurements show that the films having high transparency in the visible region and the optical band gap energy of Fe-doped TiO2 film with iron (Fe decrease with increase in iron content. These important requirements for the Fe:TiO2 films are to be used as window layers in solar cells.

  7. The role of Ar plasma treatment in generating oxygen vacancies in indium tin oxide thin films prepared by the sol-gel process

    International Nuclear Information System (INIS)

    Hwang, Deuk-Kyu; Misra, Mirnmoy; Lee, Ye-Eun; Baek, Sung-Doo; Myoung, Jae-Min; Lee, Tae Il

    2017-01-01

    Highlights: • Indium tin oxide thin film with about 41 nm thickness was obtained by the sol-gel process. • Thin film exhibited low resistivity. • Sheet resistance of thin film decreases with Ar plasma treatment time. • Ar plasma treatment on thin film does not alter the crystal structure and optical properties of the ITO thin-film. • There is no significant change in oxygen vacancies after 20 min of plasma treatment. - Abstract: Argon (Ar) plasma treatment was carried out to reduce the sheet resistance of indium tin oxide (ITO) thin films. The Ar plasma treatment did not cause any significant changes to the crystal structure, surface morphology, or optical properties of the ITO thin films. However, an X-ray photoelectron spectroscopy study confirmed that the concentration of oxygen vacancies in the film dramatically increased with the plasma treatment time. Thus, we concluded that the decrease in the sheet resistance was caused by the increase in the oxygen vacancy concentration in the film. Furthermore, to verify how the concentration of oxygen vacancies in the film increased with the Ar plasma treatment time, cumulative and continuous plasma treatments were conducted. The oxygen vacancies were found to be created by surface heating via the outward thermal diffusion of oxygen atoms from inside the film.

  8. Durable cofactor immobilization in sol-gel bio-composite thin films for reagentless biosensors and bioreactors using dehydrogenases.

    Science.gov (United States)

    Wang, Zhijie; Etienne, Mathieu; Quilès, Fabienne; Kohring, Gert-Wieland; Walcarius, Alain

    2012-02-15

    A new strategy directed to the durable immobilization of NAD(+)/NADH cofactors has been tested, along with a suitable redox mediator (ferrocene), in biocompatible sol-gel matrices encapsulating a bi-enzymatic system (a dehydrogenase and a diaphorase, this latter being useful to the safe regeneration of the cofactor), which were deposited as thin films onto glassy carbon electrode surfaces. It involves the chemical attachment of NAD(+) to the silica matrix using glycidoxypropylsilane in the course of the sol-gel process (in smooth chemical conditions). This approach based on chemical bonding of the cofactor (which was checked by infrared spectroscopy) led to good performances in terms of long-term stability of the electrochemical response. The possibility to integrate all components (proteins, cofactor, mediator) in the sol-gel layer in an active and durable form gave rise to reagentless devices with extended operational stability (i.e. high amperometric response maintained for more than 12h of continuous use under constant potential, whereas the signal completely vanished within the first few minutes of working with non-covalently bonded NAD(+)). To confirm the wide applicability of the proposed approach, the same strategy has been applied to the elaboration of biosensors for D-sorbitol, D-glucose and L-lactate with using D-sorbitol dehydrogenase, D-glucose dehydrogenase and L-lactate dehydrogenase respectively. The analytical characteristics of the glucose sensors are given and compared to previous approaches described in the literature for the elaboration of reagentless biosensors. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Photostability and moisture uptake properties of wood veneers coated with a combination of thin sol-gel films and light stabilizers

    Science.gov (United States)

    Mandla A. Tshabalala; Ryan Libert; Christian M. Schaller

    2011-01-01

    In recent years, there has been increased interest in the use of inorganic UV blocking nanoparticles for photostabilization of wood surfaces. Photostability and moisture uptake properties of wood veneers coated with a combination of hybrid inorganic-organic thin sol-gel films and organic light stabilizers was investigated. The light stabilizers were applied by brushing...

  10. Characterization of Microstructure and Performance of YBa2Cu3O7−x Films Synthesized Through Sol–Gel Aqueous Precursors with DEA/TEA Addition

    DEFF Research Database (Denmark)

    Tang, Xiao; He, Dong; Zhao, Yichun

    2013-01-01

    YBa2Cu3O7−x (YBCO) superconducting thin films are synthesized through non-fluorine sol–gel aqueous processes. Diethanolamine (DEA) and triethonalamine (TEA), which have similar molecular structures but different complexation abilities and molecular weights, are separately used as chelating agents....... Compare to DEA, the precursor with TEA additive exhibits higher stability and yields films of superior microstructure and surface morphology. Finally, the YBCO film produced from the TEA precursor displays a sharp superconducting transition, with a J c of 1.7 MA/cm2 estimated at 77 K in self field....

  11. Study of catalytic properties of sol-gel-derived CoO x -SiO2 film systems by the example of the growth of carbon nanomaterials

    Science.gov (United States)

    Levitskii, V. S.; Maksimov, A. I.; Moshnikov, V. A.; Terukov, E. I.

    2014-07-01

    Film catalytic samples in the Si-Co-O system in the composition range from 15 to 90 mol % Co have been prepared using the sol-gel technology. Carbon nanomaterials have been fabricated by pyrolytic synthesis using these films as catalysts. Raman spectroscopy of materials has shown that multiwalled carbon nanotubes are formed by pyrolysis on catalytic films containing Co3O4. The dependence of the carbon material length on the synthesis time has been considered. It has been shown that the average growth rate of tubes and fibers is ˜3 μm/min.

  12. Surface characterization of sol–gel derived indium tin oxide films on ...

    Indian Academy of Sciences (India)

    Unknown

    mental moisture trapped in the film surface. In addition, contamination of carbon from environment cannot be ruled out. As hydrogen atoms have higher ... be due to the condensation of two –OH groups of two In–. OH entities producing relatively high crystalline envi- ronment in ITO. Figure 2. Results of peak analysis of O1s ...

  13. Sol–gel deposited ceria thin films as gate dielectric for CMOS ...

    Indian Academy of Sciences (India)

    In this work, cerium oxide thin films were prepared using cerium chloride heptahydrate, ethanol and citric acid as an additive by .... LCR meter. Electrical dielectric constant and density of inter- face traps (Dit) have been determined with the help of C–V and G–V curves. 2.1 MOS structure. The MOS capacitor structure is ...

  14. Fabrication and application of mesoporous TiO{sub 2} film coated on Al wire by sol-gel method with EISA

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Linkang; Lu, Jianjun, E-mail: lujianjunktz@tyut.edu.cn

    2017-04-30

    Highlights: • Successfully fabricated mesoporous TiO{sub 2} thin film on Al wire by sol-gel method with EISA. • Ni supported on this film and exhibits good methanation performance. • Investigate the decomposition temperature of template agent F127 in TiO{sub 2} precursor system. - Abstract: Mesoporous TiO{sub 2} film on Al wire was fabricated by sol-gel method with evaporation induced self assembly (EISA) process using F127 as templating agent in the mixed solution of ethanol and Tetra-n-butyl Titanate. The Ni/TiO{sub 2} film catalyst supported on Al wire was prepared by impregnation and the catalytic performance on methanation was carried out in a titanium alloy micro-reactor tube. It was shown that anatase mesoporous TiO{sub 2} film was prepared in this conditions (1 g F127,calcined at 400 °C and aged for 24 h), which has specific surface area of 127 m{sup 2} g{sup −1} and narrow pore size distribution of 5.3 nm. Low calcined temperature (300 °C) cannot transfer film to anatase and decompose F127 completely. Ni/TiO{sub 2} film on Al wire catalyst was proved to be active in CO methanation reaction. And the CO conversion reaches 99% and CH{sub 4} selectivity close is to 80% when the reaction temperature is higher 360 °C.

  15. Silver Doped TiO2 Nanostructure Composite Photocatalyst Film Synthesized by Sol-Gel Spin and Dip Coating Technique on Glass

    Directory of Open Access Journals (Sweden)

    Mojtaba Nasr-Esfahani

    2008-01-01

    Full Text Available New composite films (P25SGF-MC-Ag, MPC500SGF-MC-Ag, and ANPSGF-MC-Ag have been synthesized by a modified sol-gel method using different particle sizes of TiO2 powder and silver addition. Nanostructure TiO2/Ag composite thin films were prepared by a sol-gel spin and dip coating technique. while, by introducing methyl cellulose (MC porous, TiO2/Ag films were obtained after calcining at a temperature of 500°C. The as-prepared TiO2 and TiO2/Ag films were characterized by X-ray diffractometry, and scanning electron microscopy to reveal the structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methyl orange (MO under UV irradiation. After 500°C calcination, the microstructure of MC-TiO2 film without Ag addition exhibited a microstructure, while significant sintering effect was noticed with Ag additions and the films exhibited a porous microstructure. Nanostructure anatase-phase TiO2 can be observed with respect to the sharpening of XRD diffraction peaks. The photodegradation of porous TiO2 deposited with 5×10−4 mol Ag exhibited the best photocatalytic efficiency, where 69% methyl orange can be decomposed after UV exposure for 1 hour.

  16. Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Mathematic and Physical Sciences, R.O.C. Air Force Academy, Kaohsiung 820, Taiwan (China); Chen, Chan-Ching; Weng, Chung-Ming [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hong, Cheng-Shong [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Tsai, Cheng-Che [Department of Digital Game and Animation Design, Tung-Fang Design University, Kaohsiung 829, Taiwan (China)

    2015-02-28

    Highly (100/110) oriented lead-free Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1−x}NbO{sub 3} (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO{sub 2}/Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (P{sub r} = 14.3 μC/cm{sup 2}), piezoelectric coefficient (d{sub 33} = 48.1 pm/V), and leakage current (<10{sup −5} A/cm{sup 2}) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields.

  17. Dosimetric parameters for small field sizes using Fricke xylenol gel, thermoluminescent and film dosimeters, and an ionization chamber

    International Nuclear Information System (INIS)

    Guzman Calcina, Carmen S; Oliveira, Lucas N de; Almeida, Carlos E de; Almeida, Adelaide de

    2007-01-01

    Dosimetric measurements in small therapeutic x-ray beam field sizes, such as those used in radiosurgery, that have dimensions comparable to or smaller than the build-up depth, require special care to avoid incorrect interpretation of measurements in regions of high gradients and electronic disequilibrium. These regions occur at the edges of any collimated field, and can extend to the centre of small fields. An inappropriate dosimeter can result in an underestimation, which would lead to an overdose to the patient. We have performed a study of square and circular small field sizes of 6 MV photons using a thermoluminescent dosimeter (TLD), Fricke xylenol gel (FXG) and film dosimeters. PMMA phantoms were employed to measure lateral beam profiles (1 x 1, 3 x 3 and 5 x 5 cm 2 for square fields and 1, 2 and 4 cm diameter circular fields), the percentage depth dose, the tissue maximum ratio and the output factor. An ionization chamber (IC) was used for calibration and comparison. Our results demonstrate that high resolution FXG, TLD and film dosimeters agree with each other, and that an ionization chamber, with low lateral resolution, underestimates the absorbed dose. Our results show that, when planning small field radiotherapy, dosimeters with adequate lateral spatial resolution and tissue equivalence are required to provide an accurate basic beam data set to correctly calculate the absorbed dose in regions of electronic disequilibrium

  18. Effect of thickness on structural, electrical, optical and magnetic properties of Co and Al doped ZnO films deposited by sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mamta [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India); Mehra, R.M. [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India)], E-mail: rammehra2003@yahoo.com

    2008-12-30

    This paper reports deposition and characterization of Zn{sub 0.94}Co{sub 0.05}Al{sub 0.01}O films of thickness ranging from 70 nm to 400 nm. These films were deposited on a glass (Corning, 7059) substrate using sol-gel route. The films have been characterized to study their structural, electrical, optical and magnetic properties. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the crystallinity and growth mode of the films. The films deposited up to a thickness of 200 nm showed improvement in crystallinity and preferential c-axis orientation. A transition in the growth mode from vertical (c-axis) to lateral (a and b-axis) was observed with further increase in the thickness of the film. The average transmittance of the films for thickness less than 200 nm was above 80% in the visible region which decreased at higher thickness of the film. The resistivity of the film was found to decrease with increase in thickness up to 200 nm. Ferromagnetism, at room temperature, was confirmed for 200 nm and 400 nm thick films.

  19. Effect of thickness on structural, electrical, optical and magnetic properties of Co and Al doped ZnO films deposited by sol-gel route

    International Nuclear Information System (INIS)

    Sharma, Mamta; Mehra, R.M.

    2008-01-01

    This paper reports deposition and characterization of Zn 0.94 Co 0.05 Al 0.01 O films of thickness ranging from 70 nm to 400 nm. These films were deposited on a glass (Corning, 7059) substrate using sol-gel route. The films have been characterized to study their structural, electrical, optical and magnetic properties. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the crystallinity and growth mode of the films. The films deposited up to a thickness of 200 nm showed improvement in crystallinity and preferential c-axis orientation. A transition in the growth mode from vertical (c-axis) to lateral (a and b-axis) was observed with further increase in the thickness of the film. The average transmittance of the films for thickness less than 200 nm was above 80% in the visible region which decreased at higher thickness of the film. The resistivity of the film was found to decrease with increase in thickness up to 200 nm. Ferromagnetism, at room temperature, was confirmed for 200 nm and 400 nm thick films.

  20. Effects of UV assistance on the properties of al-doped ZnO thin films deposited by sol-gel method

    Science.gov (United States)

    Tseng, Yung-Kuan; Pai, Feng-Ming; Chen, Yan-Cheng; Wu, Chao-Hsien

    2013-11-01

    We report here the preparation of aluminum doped zinc oxide transparent conductive thin films by a UV-assisted sol-gel method. It was found that UV irradiation creates ozone, which promotes the conductivity and transparency of the films. Boro-silicate glasses are used as substrates; an PGME is used as a solvent; after spin-coating, the films are dried and radiated with UV and then heated to 400°C for decarburization and 500°C for annealing under air. The surface morphologies of the prepared films are observed by FE-SEM and AFM. It was found that the films irradiated with UV-C are smoother and denser. An XRD analysis shows that the films have a typical wurtzite crystalline structure with a c-axis orientation normal to the surface. The electric resistance values measured with a four-point probe show that the films irradiated with UV have better conductivity (at approximately 3.4 × 10-3Ω-cm) than the films that did not undergo UV irradiation. An analysis by visible light spectrometry indicates that the AZO films irradiated with UV are more transparent than the films without UV-irradiation.

  1. Photoprocesses in 7-hydroxy coumarins molecules in solutions and SiO2 sol–gel films – Materials for optical chemical sensorics

    International Nuclear Information System (INIS)

    Selivanov, N.I.; Samsonova, L.G.; Kopylova, T.N.

    2016-01-01

    The paper investigates the spectral properties of protolytic forms of three substituted 7-hydroxy coumarin molecules in aqueous ethanol solutions and SiO 2 films. It explains spectral-and-luminescent properties of coumarins in the produced films. It is found that in aqueous ethanol solutions and sol–gel films, upon excitation in the S 1 state, there is a reaction of proton phototransfer from the O–H group of neutral coumarins molecules to the water molecule with development of anionic forms solvated by hydroxonium ions. We studied sensory properties of compounds in the films to the ammonia gas in terms of changes in their fluorescent properties and revealed the reasons causing such changes. We demonstrated the prospects of using films with one of the investigated coumarins as the ammonia gas sensitive material of an optical chemical sensor.

  2. Effect of Al and N Doping on Structural and Optical Properties of Sol-Gel Derived ZnO Thin Films

    International Nuclear Information System (INIS)

    Bangbai, C.; Chongsri, K.; Pecharapa, W.; Techitdheera, W.

    2013-01-01

    In this work, the preparation of ZnO, N-doped ZnO (NZO), Al-doped ZnO (AZO) and Al, N-doped ZnO (ANZO) thin films by the sol-gel spin-coating method is reported. The structural properties and surface morphologies of films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The XRD and SEM results disclosed that the crystallization quality and grain size of as-prepared films were highly influenced by N and Al doping. UV-VIS spectrophotometer results indicated that Al and N additives could significantly enhance the optical transparency and induce the blue-shift in optical bandgap of ZnO films. (author)

  3. Structure and characterization of Sn, Al co-doped zinc oxide thin films prepared by sol–gel dip-coating process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min-I [Institute of Materials Science and Engineering, National Central University, Taiwan (China); Laboratoire de Nanotechnologie et d' Instrumentation Optique, Institut Charles Delaunay, CNRS - UMR STMR 6279, Université de Technologie de Troyes (France); Huang, Mao-Chia [Institute of Materials Science and Engineering, National Central University, Taiwan (China); Legrand, David [Institute of Materials Science and Engineering, National Central University, Taiwan (China); Laboratoire de Nanotechnologie et d' Instrumentation Optique, Institut Charles Delaunay, CNRS - UMR STMR 6279, Université de Technologie de Troyes (France); Lerondel, Gilles [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Institut Charles Delaunay, CNRS - UMR STMR 6279, Université de Technologie de Troyes (France); Lin, Jing-Chie, E-mail: jclin4046@gmail.com [Institute of Materials Science and Engineering, National Central University, Taiwan (China)

    2014-11-03

    Transparent conductive zinc oxide co-doped with tin and aluminum (TAZO) thin films were prepared via sol–gel dip-coating process. Non-toxic ethanol was used in this study instead of 2-methoxyethanol used in conventional work. Dip-coating was repeated several times to obtain relatively thick films consisting of six layers. The films were then annealed at 500 °C for 1 h in air or in vacuum and not subsequently as employed in other studies. The X-ray diffraction patterns indicated that all the samples revealed a single phase of hexagonal ZnO polycrystalline structure with a main peak of (002). The optical band gap and resistivity of the TAZO films were in the ranges of 3.28 to 3.32 eV and 0.52 to 575.25 Ω cm, respectively. The 1.0 at.% Sn, 1.0 at.% Al co-doped ZnO thin film annealed in vacuum was found to have a better photoelectrochemical performance with photocurrent density of about 0.28 mA/cm{sup 2} at a bias of 0.5 V vs. SCE under a 300 W Xe lamp illumination with the intensity of 100 mW/cm{sup 2}. Compared to the same dopant concentration but annealed in air (∼ 0.05 mA/cm{sup 2} bias 0.5 V vs. SCE), the photocurrent density of the film annealed in vacuum was 5 times higher than the film annealed in air. Through electrochemical measurements, we found that the dopant concentration of Sn plays an important role in TAZO that affected photocurrent density, stability of water splitting and anti-corrosion. - Highlights: • Al, Sn co-doped ZnO (TAZO) films was synthesized by sol–gel process. • The parameters of TAZO films were dopant concentration and annealed ambient. • The photoelectrochemical characteristics of TAZO films were investigated.

  4. Correlation between microstructure and optical properties of nano-crystalline TiO{sub 2} thin films prepared by sol-gel dip coating

    Energy Technology Data Exchange (ETDEWEB)

    Mechiakh, R., E-mail: raouf_mechiakh@yahoo.fr [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP.95, Hammam-Lif 2050 (Tunisia); Laboratoire de Ceramiques, Universite Mentouri Constantine (Algeria); Sedrine, N. Ben; Chtourou, R. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP.95, Hammam-Lif 2050 (Tunisia); Bensaha, R. [Laboratoire de Ceramiques, Universite Mentouri Constantine (Algeria)

    2010-11-15

    Titanium dioxide thin films have been prepared from tetrabutyl-orthotitanate solution and methanol as a solvent by sol-gel dip coating technique. TiO{sub 2} thin films prepared using a sol-gel process have been analyzed for different annealing temperatures. Structural properties in terms of crystal structure were investigated by Raman spectroscopy. The surface morphology and composition of the films were investigated by atomic force microscopy (AFM). The optical transmittance and reflectance spectra of TiO{sub 2} thin films deposited on silicon substrate were also determined. Spectroscopic ellipsometry study was used to determine the annealing temperature effect on the optical properties and the optical gap of the TiO{sub 2} thin films. The results show that the TiO{sub 2} thin films crystallize in anatase phase between 400 and 800 deg. C, and into the anatase-rutile phase at 1000 deg. C, and further into the rutile phase at 1200 deg. C. We have found that the films consist of titanium dioxide nano-crystals. The AFM surface morphology results indicate that the particle size increases from 5 to 41 nm by increasing the annealing temperature. The TiO{sub 2} thin films have high transparency in the visible range. For annealing temperatures between 1000 and 1400 deg. C, the transmittance of the films was reduced significantly in the wavelength range of 300-800 nm due to the change of crystallite phase and composition in the films. We have demonstrated as well the decrease of the optical band gap with the increase of the annealing temperature.

  5. Zinc oxide films impurified with Ti and prepared by the Sol-gel method; Peliculas de oxido de zinc impurificadas con Ti y preparadas por el metodo Sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Tirado G, S. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Cazares R, J.M.; Maldonado, A. [CINVESTAV-IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico)

    2006-07-01

    Titanium-doped zinc oxide thin films have been prepared on silicon substrate using the Sol-Gel technique. The structural, morphology, electrical and optical properties of such thin films were studied as a function of titanium concentration (0.5, 1 and 1.5 %) and the thin films thickness. Zinc acetate dihydrate and titanium (VI)-oxy acetylacetonate were used as precursor materials, using 2-methoxyethanol and monoethanolamine as via. The X-ray diffraction spectra show polycrystalline films in all the cases. It can see for all the thin films a preferential growth along the (002) planes where the titanium concentration and also the thin films thickness play an important rule. No structural changes are observed at all. The surface morphology studied shows as the grain size decreases when thin thickness is increases. For titanium concentration of 0.5, 1 and 1.5 % values the grains size increase also. The thin films thickness for titanium concentration of 1.5 % was 500 nm (4v), 400 nm (3v), 180 nm (2v) and 130 nm (1v), values obtained from cross-section micrographs. Highly resistive samples are obtained for substrate soda-lime even showing high transmittance. Better physical properties are required for gas sensors or semitransparent electrodes and other possible applications. (Author)

  6. A poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)/titanium oxide nanocomposite film synthesized by sol–gel assisted electropolymerization for electrochromic application

    International Nuclear Information System (INIS)

    Lu, Jinlin; Song, Hua; Li, Suning; Wang, Lin; Han, Lu; Ling, Han; Lu, Xuehong

    2015-01-01

    In this article, we report the facile synthesis of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)/titanium dioxide (PEDOT:PSS/TiO 2 ) nanocomposite film by sol–gel assisted electropolymerization. The structure, morphology and composition of the films were investigated by different techniques, such as Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, atomic force microscope and X-ray photoelectron spectroscopy. The PEDOT:PSS/TiO 2 nanocomposite film was applied for electrochromic application. The results indicate that the PEDOT:PSS/TiO 2 nanocomposite film exhibits a higher optical contrast and a much better stability as compared to PEDOT:PSS film. The significant performance enhancement can be attributed to the nanoscale particle size and uniform size distribution of PEDOT:PSS/TiO 2 and the synergistic effect between the inorganic nano-TiO 2 and organic PEDOT:PSS material. - Highlights: • Facile synthesis of PEDOT:PSS/TiO 2 nanocomposite film by electropolymerization • PEDOT:PSS/TiO 2 film shows nano-scaled particle sizes and uniform size distribution. • PEDOT:PSS/TiO 2 film shows higher optical contrasts and faster switching speed. • PEDOT:PSS/TiO 2 film displays a good stability for electrochromic application

  7. Influence of Mg content on tailoring optical bandgap of Mg-doped ZnO thin film prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    M.N.H. Mia

    Full Text Available Tailoring optical bandgap of ZnO nanostructured thin films doped with different elements facilitates potential material for photonic applications. Different methods of fabrication process result in different optical and structural properties for the same amount of Mg content. Therefore, details investigation of structural and optical parameters, and their correlation need to be revealed to utilize the fabricated thin films. In this work, Mg-doped ZnO thin film of 200 nm thickness was fabricated by sol-gel spin coating method on a glass substrate for four different Mg content levels. Multiple layers were deposited by a spin coater to increase the film thickness. The prepared thin films were characterized by SEM, XRD, EDS, and UV–Vis spectroscopy. The spectroscopic analysis showed a uniform crystalline nanostructured surface with less structural defects, enhanced transmittance, and higher optical bandgap than that of pure ZnO nanostructured thin film. Change of Mg content from 2% to 8% facilitated tuning of bandgap in the range of 3.30–3.39 eV. Changing trend of structural and optical parameters with Mg content showed non-linear, non-monotonic relation. In-depth analysis of structural and optical properties provides crucial information to form a better view about bandgap dependency on structural parameters. Keywords: Mg-doped ZnO, MgZnO, Bandgap tuning, Sol-gel, Spin coating

  8. Titanium dioxide thin films deposited by the sol-gel technique starting from titanium oxy-acetyl acetonate: gas sensing and photocatalyst applications

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, A.; Mayen-Hernandez, S.A.; L. Olvera, M. de la [Departamento de Ingenieria Electrica-SEES, Centro de Investigacion y de Estudios Avanzados del IPN, CINVESTAV-IPN, Mexico (Mexico); Tirado-Guerra, S. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, Mexico (Mexico)

    2010-09-15

    Titanium dioxide (TiO{sub 2}) thin films were deposited onto sodocalcic glass plates by the sol-gel technique, starting from a non-alkoxide route, namely, titanium oxy-acetyl acetonate as Ti precursor. Film thickness effect on both the gas sensing and photocatalytic degradation performance was studied. The as-deposited films were annealed in air at 400 C. All the X-ray spectra of the films show a very broad-peak centered in a 2{theta} angle around 30 . In the case of the thinnest films the surface morphology is uniform and very smooth, whereas for the thickest films the corresponding surface is covered by grains with a rod-like shape with a length on the order of 140 nm. The films were tested both for two straightforward applications: ultraviolet assisted-degradation of methylene blue dissolved in water, at different times, as well as gas sensor in a controlled propane (C{sub 3}H{sub 8}) atmosphere. As the film thickness increases, the degradation of methylene blue (MB) also increases. The thickest TiO{sub 2} thin films after being exposed by 5 hours to the catalytic degradation, promoted by ultraviolet illumination, showed a final MB solution degradation in the order of 48%. This result can be associated with the increase in the effective exposed area of the TiO{sub 2} thin films. On the other hand, the exposition of the films to a controlled propane atmosphere produced a significant change in the surface electrical resistance of the films at operating temperatures of 200 C and above. In fact, in the case of the thickest TiO{sub 2} films, a dramatic electrical resistance change of non-exposed and propane exposed - 560 to 0.7 M{omega} -, was registered. The results show that TiO{sub 2} films deposited by an economical deposition technique, as is the case of the sol-gel technique, could have an important potential in industrial applications. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    Science.gov (United States)

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    2015-06-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”.

  10. Micropatterning of Multiple Photonic Colloidal Crystal Gels for Flexible Structural Color Films.

    Science.gov (United States)

    Suzuki, Noriyuki; Iwase, Eiji; Onoe, Hiroaki

    2017-06-20

    We herein report the micropatterning of flexible multiple photonic colloidal crystal gels (PCCGs) using single-layered microchannels. These patterned PCCGs exhibit structural colors that can be tuned by adjustment of the diameter and concentration of the colloidal particles in precursor solutions of N-isopropylacrylamide (NIPAM) or polyethylene glycol diacrylate (PEGDA). The precursor solutions containing dispersed colloidal particles were selectively injected into single-layered microchannels where they polymerized rapidly. The shape, density, and height of the patterned PCCG pixels were determined by the microchannels, which in turn determined the optical properties of the PCCG arrays. Furthermore, the preparation of three different types of PCCGs exhibiting three different structural colors at a high pixel density was demonstrated successfully using the single-layered polydimethylsiloxane (PDMS) microchannels. Finally, the optical reflective properties and the mechanical flexibility of the patterned multiple PCCG arrays were evaluated. We expect that our method for the preparation of such patterned PCCG arrays will contribute to the development of flexible optical devices.

  11. Uso de sílica e sílica-titânia organofuncionalizadas para a remoção de Cu(II em aguardentes The use of organofuncionalized silica and silica-titania for Cu (II removal in spirits

    Directory of Open Access Journals (Sweden)

    Leonardo B. Cantanhede

    2005-09-01

    Full Text Available Devido a necessidade da presença de cobre nos alambiques e as exigências cada vez mais acirradas com relação ao seu teor no destilado, é de interesse o desenvolvimento de metodologias para o controle deste metal nos destilados e/ou a sua remoção até níveis aceitáveis, em conformidade com as legislações nacional e internacional. Este trabalho investigou a potencialidade de dois sólidos: sílica modificada com trimetóxisili(propiletilenodiamina (Si-Dia, e sílica-titânia, também modificada com trimetóxisili(propiletilenodiamina (Si-Ti-Dia, como agentes removedores de íons Cu2+. Foram empregadas tanto soluções padrão de Cu2+, com teor alcoólico que simulavam aguardentes, como amostras reais de destilados. Os resultados indicam que um grama das matrizes Si-Dia e Si-Ti-Dia adsorvem 1,39 e 73,5mmol de Cu2+, respectivamente, a partir das soluções padrão, nas seguintes condições: tempo de contato 22h, pH 4,0; temperatura 25 ± 1,0°C e agitação constante. Para amostras reais, sob as mesmas condições de análises, o sólido Si-Dia reduziu as concentrações dos íons divalentes Cu, Zn e Fe em, respectivamente, 82, 83 e 64%, enquanto o Si-Ti-Dia, reduziu os mesmos íons em 88, 31 e 22%, respectivamente.The high levels of copper in Brazilian spirits is a problem of prominent importance, taking into account the relevance of this metal. This work investigates the efficiency of two solids: silica organofunctionalized with thimethoxysil(propil ethylenediamine (Si-Dia and silica-titania modified with the same organofunctionaling agent (Si-Ti-Dia as copper sequestrating agents in a Brazilian spirit obtained from sugar cane. It was verified that the matrices Si-Dia and Si-Ti-Dia are very good sequiestrating agents, reducing the concentrations of Cu, Zn and Fe in the studied spirit sample in 82, 83 and 64% and 88, 31 and 22%, respectively at 25 ± 1.0°C and pH 4.0.

  12. Low-temperature perovskite-type cadmium titanate thin films derived from a simple particulate sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M.R. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Department of Materials Science and Engineering, Sharif University of Technology, Azadi Street, Tehran (Iran, Islamic Republic of)], E-mail: mrm41@cam.ac.uk; Fray, D.J. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2009-02-15

    Low-temperature perovskite-type cadmium titanate (CdTiO{sub 3}) with a nanocrystalline and mesoporous structure was prepared at various Ti:Cd molar ratios by a straightforward particulate sol-gel route. The prepared sols had a narrow particle size distribution, in the range 23-26 nm. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the powders contained a mixture of ilmenite-CdTiO{sub 3}, perovskite-CdTiO{sub 3}, anatase and rutile phases, depending on the annealing temperature and the Ti:Cd molar ratio. Perovskite-CdTiO{sub 3} was the major type obtained from cadmium-prominent powders at low temperature, whereas ilmenite-CdTiO{sub 3} was the major type obtained from titanium-prominent powders at high temperature. It was observed that the anatase-to-rutile phase transformation accelerated with decreasing Ti:Cd molar ratio. Furthermore, the ilmenite-to-perovskite phase transformation accelerated with a decrease in both the Ti:Cd molar ratio and the annealing temperature. The crystallite sizes of the ilmenite- and perovskite-CdTiO{sub 3} phases reduced with increasing the Ti:Cd molar ratio. Field emission scanning electron microscopic analysis revealed that the average grain size of the thin films decreased with an increase in the Ti:Cd molar ratio. Moreover, atomic force microscope images showed that CdTiO{sub 3} thin films had a columnar-like morphology. Based on Brunauer-Emmett-Taylor analysis, cadmium titanate powder containing Ti:Cd = 75:25 showed the greatest surface area and roughness and the smallest pore size among all the powders annealed at 500 deg. C. This is one of the smallest crystallite sizes and largest surface areas reported in the literature, and can be used in many applications in areas from optical electronics to gas sensors.

  13. Structural and magnetic study of CoCr{sub 2}O{sub 4} thin films obtained by employing the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Del Toro, A.D.; Garcia, R.P.; Davila, Y.G.; Gomes, J.L.; Goncalves, L.P.; Hernandez, E.P. [Universidade Federal de Pernambuco (UFPE), PE (Brazil)

    2016-07-01

    Full text: In this work we made a study about the structural and magnetic properties of cobalt chromite. We obtained samples in a film format and also in chromite nanopowder. Both, the powder and films were fabricated by the sol-gel chemical method, the film were deposited by the spin coating technique followed by an appropriate heat treatment at 500 °C. The used substrate was glass based on silica and we studied the rotating speed parameter during deposition. The initial aim of the work was the study of the influence of rotating speed on the quality of cromite films. The crystallinity of samples was confirmed by diffraction X-ray (XRD). The lattice parameters were determined using the Rietveld method from which we calculate grain size of 8.6 nm. The scanning electron microscopy (SEM) showed granular films with good homogeneity and we observed the dependence of the rotating speed on the quality of the deposited films. The magnetic properties were measured using a vibrating sample magnetometer (VSM). For powder samples we obtained Curie temperature of 94 K, which is a phase transition from ferrimagnetic to paramagnetic. The applied magnetic field during in the characterization of the film was oriented parallel to the plane of the substrate and we observed a high coercivity. The Curie temperature value for the films was 93 K, similar to the powder samples. (author)

  14. Preparation of silane-functionalized silica films via two-step dip coating sol-gel and evaluation of their superhydrophobic properties

    Science.gov (United States)

    Ramezani, Maedeh; Vaezi, Mohammad Reza; Kazemzadeh, Asghar

    2014-10-01

    In this paper, we study the two-step dip coating via a sol-gel process to prepare superhydrophobic silica films on the glass substrate. The water repellency of the silica films was controlled by surface silylation method using isooctyltrimethoxysilane (iso-OTMS) as a surface modifying agent. Silica alcosol was synthesized by keeping the molar ratio of ethyltriethoxysilane (ETES) precursor, ethanol (EtOH) solvent, water (H2O) was kept constant at 1:36:6.6 respectively, with 6 M NH4OH throughout the experiment and the percentages of hydrophobic agent in hexane bath was varied from 0 to 15 vol.%. The static water contact angle values of the silica films increased from 108° to 160° with an increase in the vol.% of iso-OTMS. At 15 vol%. of iso-OTMS, the silica film shows static water contact angle as high as 160°. The superhydrophobic silica films are thermally stable up to 440 °C and above this temperature, the silica films lose superhydrophobicity. By controlling the primer particle size of SiO2 about 26 nm, leading to decrease the final size of silica nanoparticles after modification of nanoparticles by isooctyltrimethoxysilane about 42 nm. The films are transparent and have uniform size on the surface. The silica films have been characterized by atomic force microscopy (AFM), fourier transform infrared spectroscopy (FT-IR), transparency, contact angle measurement (CA), Zeta-potential, Thermal stability by TG-DTA analysis.

  15. Synthesis of 8YSZ-LSGM Composite Thick Film Ceramics for Solid Electrolyte From Nanopowder Utilizing Local Zircon Prepared Using Sol Gel Process

    Science.gov (United States)

    Syarif, Dani Gustaman; Soepriyanto, Syoni; Ismunandar, Korda, Akhmad

    2010-10-01

    Thick film ceramics of 8% mol Y2O3 doped-ZrO2 (8YSZ)-La0.8Sr0.2Ga0.2Mg0.8O3 (LSGM) composite for solid electrolyte have been synthesized from nanopowder. Concentration of LSGM was 0 and 10% weight. A paste for the thick films was made from 8YSZ nanopowder prepared using sol gel method and LSGM powder prepared by solid state reaction. Precursors for the 8YSZ nanopowder preparation were ZrOCl2ṡ8H2O derived from local zircon as byproduct of Tin processing at Bangka Island using caustic fussion method, and Y(NO3)3. The thick films were produced by screen printing technique on alumina substrates. The films were sintered at 1500° C for 2 hours in air. X-ray diffraction (XRD) data showed that the nanopowder of 8YSZ was well produced with broad peaks. The particle size of the 8YSZ powder was about 12 nm as calculated using Debye Scherrer method. The thick films of 8YSZ and 8YSZ-LSGM (90:10 in weight %) composite could be produced, however, the films still contain voids. The ionic conductance of the YSZ-10LSGM films was smaller than that of the YSZ films.

  16. Ferroelectric Properties of CaBi4Ti4O15 Thin Films on Ito/glass Substrates Prepared by Sol-Gel Technology

    Science.gov (United States)

    Cheng, Chien-Min; Kuan, Ming-Chang; Chen, Kai-Hunag; Tsai, Jen-Hwan

    In this study, ferroelectric CaBi4Ti4O15 (CBT) thin films prepared by sol-gel method and deposited on ITO/glass substrates for applications in system-on-panel (SOP) devices were fabricated and investigated. The electrical and physical characteristics of as-deposited and annealed CBT thin films for metal-ferroelectric-metal (MFM) structures was discussed and investigated. In addition, the ferroelectric properties in annealed CBT thin films on ITO/glass substrate showed and exhibited clear polarization versus electrical field curves. From p-E curves, the 2Pr value and coercive field of annealed CBT thin films were calculated to be 10μC/cm2 and 180 kV/cm, respectively. Finally, the maximum capacitance, leakage current density, and transmittance within the ultraviolet-visible (UV-vis) spectrum were also investigated and discussed.

  17. Optical and electrical properties study of sol-gel derived Cu2ZnSnS4 thin films for solar cells

    Directory of Open Access Journals (Sweden)

    B. L. Guo

    2014-09-01

    Full Text Available The fabrication of environmental-friendly Cu2ZnSnS4 (CZTS thin films with pure kesterite phase is always a challenge to researchers in the field of solar cells. We introduce a simple non-vacuum sol-gel method to fabricate kesterite CZTS films. Ethylenediamine is used as the chelating agent and stabilizer and plays an important role in preparing stable precursor. X-ray diffraction, Raman and scanning electron microscopy studies suggest that the microstructure and optical properties of CZTS films depend strongly on annealing temperatures. The temperature dependence of conductivity of 500 °C annealed CZTS film shows that the Mott law dominates in the low temperature region and thermionic emission is predominant at high temperatures.

  18. Hydroxyapatite and fluor-hydroxyapatite layered film on titanium processed by a sol-gel route for hard-tissue implants.

    Science.gov (United States)

    Kim, Hae-Won; Knowles, Jonathan C; Salih, Vehid; Kim, Hyoun-Ee

    2004-10-15

    A double-layered coating, consisting of a hydroxyapatite (HA) outer film and a fluor-hydroxyapatite (FHA) inner film, was produced on a Ti substrate by a sol-gel route to improve the biocompatibility and functionality of the system. Dissolution behavior of and in vitro cellular responses to the layered film were investigated. Calcium nitrate and triethyl phosphite were used for calcium and phosphate precursors, respectively, and ammonium fluoride was added as a fluorine-ion source for FHA. The FHA layer was deposited on Ti by spin coating and subsequent heat treatment at 550 degrees C for 30 min in air, and then the HA layer was laid down over the FHA-coated Ti under the same conditions. After heat treatment, characteristic apatite structures and phases were developed on both FHA and HA films. The cross-section view of the HA/FHA film clearly showed a double-layered structure on Ti with each layer approximately 0.6-0.8-microm thickness. The coating layer was highly uniform and dense, and adhered to Ti substrate strongly with an adhesion strength of about 40 MPa. The in vitro solubility of the HA/FHA layered film in a physiological solution was between that of HA and FHA pure film, and the dissolution profile was quite biphasic, that is, an initial rapid period and a slowdown with increasing time, reflecting the gradient solubility of the fast HA outer structure/slow FHA inner structure. The human osteoblast-like HOS TE85 cells cultured on the HA/FHA layered film attached, spread, and grew favorably. The proliferation rate of the cells on the layered film was significantly higher (considered at p < 0.05 for n = 6) than that on Ti substrate and was similar to that on pure HA film. The alkaline phosphatase (ALP) activity and osteocalcin (OC) produced by the cells on the layered film were significantly higher (considered at p < 0.05 for n = 6) than those on Ti substrate. Moreover, the ALP and OC levels of cells on the layered film showed the trends of HA outer

  19. Co3O4/TiO2 films obtained by laser ablation and sol-gel for the reaction of oxygen liberation in alkaline medium

    International Nuclear Information System (INIS)

    Perez A, J.; Fernandez V, S. M.; Escobar A, L.; Jimenez B, J.

    2008-01-01

    The laser ablation technique known as Pulsed Laser Deposition (PLD) is used for obtaining thin films of TiO 2 /SnO 2 , which was later modified with Co 3 O 4 by PLD or by sol-gel technique. The films were characterized by X-ray diffraction, ultraviolet Vis and Raman spectroscopies, scanning electron microscopy and energy analysis of the dispersed X-rays produced by Auger decay. The anatase phase with particles of nano metric size was obtained by depositing the titanium dioxide in argon atmosphere. The Co 3 O 4 films obtained by PLD on the TiO 2 showed the same morphology. The electrocatalytic activity of the films that were used as photo anodes for the reaction of oxygen liberation was carried out in the darkness, with environment light and the light emitted by a xenon lamp. The current density was higher for films of Co 3 O 4 /TiO 2 /SnO 2 obtained by PLD that for cobalt dioxide of mixed valence obtained by sol-gel. (Author)

  20. Bulk and thick films of the superconducting phase YBa2Cu3O7/sub -//sub y/ made by controlled precipitation and sol-gel processes

    International Nuclear Information System (INIS)

    Barboux, P.; Tarascon, J.M.; Greene, L.H.; Hull, G.W.; Bagley, B.G.

    1988-01-01

    The synthesis of high-temperature superconducting oxides using solution chemistry has been investigated and physical properties are compared to ceramics obtained by conventional solid-state reactions. We report on controlled precipitation and sol-gel processes, both of which produce materials with particle sizes smaller than 5 μm. We find that the superconducting properties of the high T/sub c/ ceramics are affected by their manner of preparation, such that the transitions are slightly lower in temperature, but sharper, for samples made by solution rather than solid-state chemistry. The ability to prepare stable viscous gels provides an opportunity for obtaining large areas of superconducting coatings. For thick films on alumina or silicon substrates, contamination from the substrate is shown to be a problem. Finally, we observe that the sol-gel process lowers the synthesis temperature by 100 0 C.ing,

  1. Advancements in artificial heart valve disks using nano-sized thin films deposited by CVD and sol-gel techniques

    International Nuclear Information System (INIS)

    Kousar, Y.; Ali, N.; Neto, V.F.; Mei, S.; Gracio, J.

    2003-01-01

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although, PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti- coagulation drugs on a regular basis in order to minimise the formation of thrombosis. However, the anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, namely, strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and the coefficient of friction values were obtained from the pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also, in this paper we report the preparation of free standing nanocrystalline diamond films (FSND) using the time-modulated chemical vapor deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO/sub 2/) coatings. The as-grown nc-TiO/sub 2/ coatings were characterized for microstructure using SEM and XRD analysis. (author)

  2. Application of a nanostructured platform and imprinted sol-gel film for determination of chlorogenic acid in food samples.

    Science.gov (United States)

    Ribeiro, Carla M; Miguel, Eliane M; Silva, Jonadab Dos S; Silva, Cristian B da; Goulart, Marília O F; Kubota, Lauro T; Gonzaga, Fabiano B; Santos, Wilney J R; Lima, Phabyanno R

    2016-08-15

    Chlorogenic acid (CGA) is a polyphenol derivative that widely exists in higher plants like fruits, vegetables, black teas, and some traditional Chinese medicines. In this work, we have proposed a sensitive and selective electrochemical sensor for detection of CGA. The sensor was based on a glassy carbon electrode (GCE) modified with a functional platform by grafting vinyltrimethoxysilane (VTMS) in multi-walled carbon nanotubes (MWCNTs) and covered by a molecularly imprinted siloxane (MIS) film prepared using the sol-gel process. The VTMS was grafted onto the surface of the MWCNTs via in situ free radical polymerization. The MIS was obtained from the acid-catalyzed hydrolysis/condensation of a solution consisting of tetraethoxysilane (TEOS), phenyltriethoxysilane (PTEOS), (3-aminopropyl)trimethoxysilane (APTMS), and CGA as a template molecule. The modification procedure was evaluated by differential pulse voltammetry (DPV) and scanning electron microscopy (SEM). Under optimized operational conditions, a linear response was obtained covering a concentration ranging from 0.08μmolL(-1) to 500μmolL(-1) with a detection limit (LOD) of 0.032μmolL(-1). The proposed sensor was applied to CGA determination in coffee, tomato, and apple samples with recoveries ranging from 99.3% to 108.6%, showing a promising potential application in food samples. Additionally, the imprinted sensor showed a significantly higher affinity for target CGA than the non-imprinted siloxane (NIS) sensor. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Nanostructure investigation of polymer solutions, polymer gels, and polymer thin films

    Science.gov (United States)

    Lee, Wonjoo

    This thesis discusses two systems. One is structured hydrogels which are hydrogel systems based on crosslinked poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) containing micelles which form nanoscale pores within the PDMAEMA hydrogel. The other is nanoporous block copolymer thin films where solvent selectivity is exploited to create nanopores in PS-b-P4VP thin films. Both of these are multicomponent polymer systems which have nanoscale porous structures. 1. Small angle neutron scattering of micellization of anionic surfactants in water, polymer solutions and hydrogels. Nanoporous materials have been broadly investigated due to the potential for a wide range of applications, including nano-reactors, low-K materials, and membranes. Among those, molecularly imprinted polymers (MIP) have attracted a large amount of interest because these materials resemble the "lock and key" paradigm of enzymes. MIPs are created by crosslinking either polymers or monomers in the presence of template molecules, usually in water. Initially, functional groups on the polymer or the monomer are bound either covalently or noncovalently to the template, and crosslinking results in a highly crosslinked hydrogel. The MIPs containing templates are immersed in a solvent (usually water), and the large difference in the osmotic pressure between the hydrogel and solvent removes the template molecules from the MIP, leaving pores in the polymer network containing functionalized groups. A broad range of different templates have been used ranging from molecules to nanoscale structures inclucing stereoisomers, virus, and micelles. When micelles are used as templates, the size and shape before and after crosslinking is an important variable as micelles are thermodynamic objects whose structure depends on the surfactant concentration of the solution, temperature, electrolyte concentration and polymer concentration. In our research, the first goal is to understand the micellization of anionic

  4. Synthesis of chitin nanofibers, MWCNTs and MnO2 nanoflakes 3D porous network flexible gel-film for high supercapacitive performance electrodes

    Science.gov (United States)

    Liu, Shengnan; Li, Dagang

    2017-03-01

    As the porous structure and conductivity result in improvement of electrochemical properties, the chitin nanofibers (ChNFs), multi-walled carbon nanotubes (MWCNTs) and MnO2 (manganese dioxide) nanoflakes 3D porous network core-shell structure gel-film was fabricated for flexible free-standing supercapacitor electrodes. The electrodes were characterized by various techniques and the results demonstrate that the as-synthesized ChNFs/MWCNTs/MnO2 gel-film electrodes exhibits excellent supercapacitive behaviours. The ChNFs/MWCNTs/MnO2 gel-film electrode shows a high capacitance of 295.2 mF/cm2 at 0.1 mA/cm2 in 1 M Na2SO4 aqueous electrolyte because of its 3D porous structure. Furthermore, the electrodes also showed surprising cycling stability for 5000 cycles with retention rate up to 157.14% at 1 mA/cm2. The data presents great promise in the application of high-performance flexible supercapacitors with the low cost, light-weight and excellent cycling ability.

  5. Insights into the annealing process of sol-gel TiO2 films leading to anatase development: The interrelationship between microstructure and optical properties

    Science.gov (United States)

    Blanco, E.; Domínguez, M.; González-Leal, J. M.; Márquez, E.; Outón, J.; Ramírez-del-Solar, M.

    2018-05-01

    The microstructure and optical properties of TiO2 thin films, prepared by the sol-gel dip coating technique on glass substrates, were inspected. After deposition, the films were annealed at several temperatures in the 400-850 °C range and the resulting nanostructured films were studied by different techniques showing that their structural and optical characteristics evolved significantly with the increased annealing temperature. The analysis of these results by the assumption of the Tauc Lorenz model and the use of Wemple-DiDomenico equation leads to a correlation between microstructural aspects and optical characteristics of the films. Thus, crystallization processes (nucleation, growth and phase transformation) and the evolution of films texture and thickness with increasing annealing temperatures are related with the variation of the refractive index, average gap and extinction coefficient during annealing. Finally, the free-carrier concentration in the films, estimated from the Spitzer-Fan model, ranged from 1.44 × 1019 cm-3 to 3.07 × 1019 cm-3 with the changing annealing temperature, which is in agreement with those obtained in similar anatase thin films from electrical measurement techniques.

  6. Subzero Temperature Dip-Coating of Sol-Gel Vanadium Pentoxide: Effect of the Deposition Temperature on the Film Structure, Morphology, and Electrochromic Properties

    Directory of Open Access Journals (Sweden)

    Afaf Almoabadi

    2016-01-01

    Full Text Available Vanadium pentoxide sol-gel prepared thin films were deposited on indium-tin-oxide (ITO substrates by dip-coating at a subzero temperature (−10°C. The structure, morphology, and optical and electrochromic properties of dense and porous vanadium oxide films coated at low temperature were determined and compared to those of the corresponding films deposited under room-temperature conditions. The results indicated that, in the films coated at −10°C, a residual compressive stress exists that would originate from the formation of microvoids during the deposition. These microvoids are preserved during the heat treatment of the films. The microvoid morphology would favor the formation of nanostructures that would be responsible for the improved electrochromic properties of the subzero dip-coated films. Low-temperature coated films, heated at 450°C for several hours, undergo the transformation from a layered to a highly uniform nanorod structure that would be an important feature for different applications.

  7. Structural and Luminescence Properties of Lu2O3:Eu3+ F127 Tri-Block Copolymer Modified Thin Films Prepared by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    María Luz Carrera Jota

    2013-02-01

    Full Text Available Lu2O3:Eu3+ transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation. Structural, morphological, and optical properties of the films were investigated for different F127/Lu molar ratios (0–5 in order to obtain high optical quality films with enhanced thickness compared with the traditional method. X-ray diffraction (XRD shows that the films present a highly oriented cubic structure beyond 1073 K for a 3-layer film, on silica glass substrates. The thickness, density, porosity, and refractive index evolution of the films were investigated by means of m-lines microscopy along with the morphology by scanning electron microscope (SEM and luminescent properties.

  8. Enhancement of the Ultraviolet Photoresponsivity of Al-doped ZnO Thin Films Prepared by using the Sol-gel Spin-coating Method

    Science.gov (United States)

    Lee, Wookbin; Leem, Jae-Young

    2018-03-01

    We report the structural, morphological, optical, and ultraviolet (UV) photoresponse properties of Al-doped ZnO (AZO) thin films prepared on silicon substrates with different Al doping concentrations by using the sol-gel spin-coating method. An analysis of the X-ray diffraction patterns of the AZO thin films revealed that the average grain size decreased and the c-axis lattice constant increased with Al content. The field-emission scanning electron microscopy images showed that with Al doping, the grain size decreased, but the film density increased with increasing Al doping concentration from 0% to 3%. These results indicate that the surface area of the film increased with increasing Al doping. The absorbance spectra revealed that the UV absorbance of the AZO thin films increased with increasing Al doping concentration and that the absorption onset shifted towards lower energies. The photoluminescence spectra revealed that with increasing Al doping, the intensity of the visible emission greatly decreased and the visible emission peak shifted forward lower energy (a red shift). The UV sensor based on the AZO thin films exhibited a higher responsivity than that based on the undoped ZnO thin film. Therefore, this study provides a facile method for improving the photoresponsivity of UV sensors.

  9. Structural and electrical properties of Nb doped TiO{sub 2} films prepared by the sol–gel layer-by-layer technique

    Energy Technology Data Exchange (ETDEWEB)

    Duta, M., E-mail: mduta@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Simeonov, S. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Teodorescu, V. [National Institute of Material Physics, 105 bis Atomistilor Street, 077125 Bucharest, Magurele (Romania); Predoana, L.; Preda, S.; Nicolescu, M.; Marin, A. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Spasov, D. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Gartner, M.; Zaharescu, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Szekeres, A. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria)

    2016-02-15

    Highlights: • TiO{sub 2}:Nb (1.2 at.%) multilayer films were deposited by sol–gel method on glass and Si. • 5 and 10 layers TiO{sub 2}:Nb films crystallize only in the anatase phase. • E{sub g} values are within 3.24–3.32 eV showing a decrease with increasing the layer number. • The specific resistivity, effective donor and sheet energy densities were obtained. • Nb donor compensation by acceptor levels in TiO{sub 2}:Nb film was suggested. - Abstract: Thin films of 5 and 10-layered sol–gel TiO{sub 2} were doped with 1.2 at.% Nb and their structural, optical and electrical properties were investigated. The films crystallized only in anatase phase, as evidenced by X-ray diffraction and selected area electron diffraction analyses. High resolution transmission electron microscopy revealed nanosized crystallites with amorphous boundaries. Current-voltage measurements on metal-TiO{sub 2}–Si structures showed the formation of n{sup +}–n heterojunction at the TiO{sub 2}–Si interface with a rectification ratio of 10{sup 4}. The effective donor density varies between 10{sup 16} and 10{sup 17} cm{sup −3}, depending on film thickness. The sheet energy densities under forward and reverse bias are in the order of 10{sup 12} and 10{sup 10} cm{sup −2} eV{sup −1}, respectively. These values and the high specific resistivity (10{sup 4} Ω cm) support the existence of compensating acceptor levels in these films. It was established that the conduction mechanism is based on space charge limited current via deep levels with different energy positions in the band gap.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  11. In situ formation of silver nanostructures produced via laser irradiation within sol-gel derived films and their interaction with a fluorescence tagged protein.

    Science.gov (United States)

    Hungerford, Graham; Toury, Marion; McLoskey, David; Finnigan, Scott; Gellie, Shaun; Holmes-Smith, A Sheila

    2010-11-28

    The presence of a conducting metal surface is known to affect the emission of a fluorophore in its proximity. This can lead to an enhancement in its fluorescence intensity along with a decrease in the fluorescence lifetime. This phenomenon, sometimes known as metal enhanced fluorescence, has implications in the area of sensing and "lab on a chip" applications. Here controlled, localised use of metallic structures can be advantageous in enhancing the detection of a fluorescent signal. The sol-gel technique has been demonstrated as a useful method by which to produce a biocompatible material. The versatility of the reaction allows for the inclusion of metal ions, which can form metallic nanostructures permitting the potential enhancement of fluorescence to be exhibited. In this work we incorporate silver nitrate within silica sol-gel derived films produced using a simple procedure at relative low temperatures (close to ambient). A compact time-resolved fluorescence microscope equipped with a semiconductor laser was used to photoactivate the silver ions to form localised metallic structures within the films. Patterning was achieved by computer control of the microscope stage and using the laser in CW mode. The films were characterised using AFM and UV-vis spectroscopy to ascertain the presence of the photoactivated silver nanostructures. The effect of the presence of these structures was elucidated by studying the time-resolved fluorescence of FITC labelled bovine serum albumin adsorbed to the films, where a decrease in the lifetime of the FITC label was observed in the location of the nanostructures.

  12. Structure/Property Relationships for Sol-gel Derived YBa2Cu3O7-d and SrTiO3 Films

    Science.gov (United States)

    Dawley, Jeff; Clem, Paul; Siegal, Michael; Overmyer, Don

    2001-03-01

    Solution deposition of c-axis oriented YBa2Cu3O7-d (YBCO) films on buffered RABiT substrates is a potential method for rapid, low cost production of superconducting tapes for power transmission and other applications. For this work, 100-250 nm thick YBCO and SrTiO3 (STO) films have been prepared by spin-coating and dip-coating sol-gel solutions onto LaAlO3 (100) and RABiT Ni (200) substrates. Biaxially textured STO coatings have been deposited on LaAlO3 and RABiT Ni by using a "templating" technique and controlling growth temperature and pO2. YBCO films grown on STO coated LaAlO3 possess comparable superconducting properties to YBCO films grown directly on LaAlO3 ( 1 MA/cm2 at 77K), indicating that a high quality STO layer does not degrade the crystalline quality of the YBCO. The effects of processing parameters on the STO buffer layer and novel processing techniques for decreasing the processing time and simplifying the integration of sol-gel YBCO with Ni substrates will be discussed. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Company, for the US Dept. Of Energy under contract DE-AC04-94A185000.

  13. Fabrication and gas sensitivity of SnO2 hierarchical films with interwoven tubular conformation by a biotemplate-directed sol gel technique

    Science.gov (United States)

    Dong, Qun; Su, Huilan; Zhang, Di; Zhang, Fangying

    2006-08-01

    A facile and versatile method is reported to fabricate the interwoven tubular hierarchy of SnO2 films using a biotemplate eggshell membrane (ESM) combined sol-gel approach. In order to promote the crystallization of SnO2 films, calcination is necessary and can adjust the size of the building units in the range 2.8-26 nm. Under the direction of ESM biomacromolecules, SnO2 nanocrystallites come into being and assemble into nanotubes, and further pattern porous hierarchical meshworks to faithfully retain the morphology of natural ESM. The sensor performance of as-prepared biomorphic SnO2 was measured for ethanol, liquefied petroleum gas (LPG), H2S, and gasoline. It is found that the SnO2 hierarchical films obtained have a good selectivity for LPG with a working temperature above 300 °C while for ethanol below 270 °C.

  14. Preparation and optical properties of ZnGa{sub 2}O{sub 4}:Cr{sup 3+} thin films derived by sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Weiwei [School of Physics and Nuclear Energy Engineering, Beihang University, No. 37 XueYuan Road, HaiDian District, Beijing 100191 (China); Zhang Junying, E-mail: zjy@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, No. 37 XueYuan Road, HaiDian District, Beijing 100191 (China); Li Yuan; Chen Ziyu; Wang Tianmin [School of Physics and Nuclear Energy Engineering, Beihang University, No. 37 XueYuan Road, HaiDian District, Beijing 100191 (China)

    2010-05-01

    ZnGa{sub 2}O{sub 4}:Cr{sup 3+} thin films with bright red emission were synthesized using a sol-gel process, characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Auger electron spectroscopy (AES) and UV-vis and fluorescence spectrophotometry measurements. Effects of calcining temperature, film thickness, calcining duration and substrates on the crystal structure and photoluminescent property have been investigated. It is found that the crystallinity, Ga/Zn ratio and band gap energy (E{sub g}) are significant factors influencing optical characteristics, while the nature of substrates affect the surface morphologies of ZnGa{sub 2}O{sub 4}:Cr{sup 3+} thin films.

  15. Annealing temperature effect on the properties of mercury-doped TiO{sub 2} films prepared by sol-gel dip-coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Mechiakh, R., E-mail: raouf_mechiakh@yahoo.fr [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar Batna, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Ben Sedrine, N. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Karyaoui, M. [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar Batna, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Chtourou, R. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia)

    2011-04-15

    This work presents the annealing temperature effect on the properties of mercury (Hg)-doped titanium dioxide (TiO{sub 2}). Thin films and polycrystalline powders have been prepared by sol-gel process. The structure, surface morphology and optical properties, as a function of the annealing temperature, have been studied by atomic force microscopy (AFM), Raman, reflectance and ellipsometric spectroscopies. In order to determine the transformation points, we have analyzed the xerogel-obtained powder by differential scanning calorimetry (DSC). Raman spectroscopy shows the crystalline anatase and rutile phases for the films annealed at 400 deg. C and 1000 deg. C respectively. The AFM surface morphology results indicate that the particle size increases from 14 to 57 nm by increasing the annealing temperature. The complex index and the optical band gap (E{sub g}) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreases by increasing the annealing temperature.

  16. Fabrication of ZnO Thin Films by Sol-Gel Spin Coating and Their UV and White-Light Emission Properties

    Science.gov (United States)

    Kumar, Mirgender; Dubey, Sarvesh; Rajendar, Vanga; Park, Si-Hyun

    2017-10-01

    ZnO thin films have been fabricated by the sol-gel spin-coating technique and annealed under different conditions, and their ultraviolet (UV) and white-light emission properties investigated. Different ambient conditions including oxygen, nitrogen, zinc-rich nitrogen, and vacuum were used to tune the main properties of the ZnO thin films. The resistivity varied from the conductive to semi-insulating regime, and the luminescence emission from fairly intense UV to polychromatic. The emission intensity was also found to be a function of the annealing conditions. Possible routes to compensate the loss of emission characteristics are discussed. X-ray photoelectron spectroscopy (XPS) analysis was carried out to detect the chemical states of the zinc/oxygen species. The changes in the electrical and emission properties are explained based on annihilation/formation of inherent donor/acceptor-type defects. Such ZnO thin films could have potential applications in solid-state lighting.

  17. Enhanced self-repairing capability of sol-gel derived SrTiO3/nano Al2O3 composite films

    International Nuclear Information System (INIS)

    Yao, Manwen; Peng, Yong; Xiao, Ruihua; Li, Qiuxia; Yao, Xi

    2016-01-01

    SrTiO 3 /nano Al 2 O 3 inorganic nanocomposites were prepared by using a conventional sol-gel spin coating process. For comparison, SrTiO 3 films doped by equivalent amount of sol-Al 2 O 3 have also been investigated. Aluminum deposited by using vacuum evaporation was used as the top electrode. The nanocomposites exhibited a significantly enhanced dielectric strength of 506.9 MV/m, which was increased by 97.4% as compared with the SrTiO 3 films doped with sol-Al 2 O 3 . The leakage current maintained of the same order of microampere until the ultimate breakdown of the nanocomposites. The excellent electrical performances are ascribed to the anodic oxidation reaction in origin, which can repair the internal and/or surface defects of the films.

  18. Structural and photodegradation behaviors of Fe{sup 3+}-doping TiO{sub 2} thin films prepared by a sol–gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Huey-Jiuan; Yang, Tien-Syh [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2014-10-15

    Highlights: • Pure and various Fe{sup 3+}-doped TiO{sub 2} thin films have been successfully fabricated. • The phase of all thin films was single phase of anatase TiO{sub 2} when calcined at 823 K. • The crystallinity of TiO{sub 2} thin films decreased as Fe{sup 3+}-doping increased. • The photodegradation of each sample increased as the irradiation time increased. • The photodegradation increased as Fe{sup 3+}-doping increased at a fixed irradiation time. - Abstract: Pure and various Fe{sup 3+}-doping TiO{sub 2} thin films have been successfully fabricated on glass substrate prepared by a sol–gel spin coating route. The structural and photodegradation behavior of these films after calcined at various temperatures for 1 h were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectrum and degradation of 1.0 × 10{sup −5} M methylene blue solution. When all thin films after calcined at 823 K for 1 h, the crystalline phase are comprised only contained single phase of anatase TiO{sub 2}. The crystallinity of various Fe{sup 3+}-doping TiO{sub 2} thin films decreases with Fe{sup 3+}-doping concentration increased. The PL intensity of all thin films also decreases with Fe{sup 3+}-doping concentration increased. When all various Fe{sup 3+}-doping TiO{sub 2} thin films after calcined at 823 K for 1 h, the photodegradation of each sample increases with irradiation time increased. Moreover, the photodegradation also increases with Fe{sup 3+}-doping concentration increased when fixed at constant irradiation time.

  19. Comprehensive Study of Sol-Gel versus Hydrolysis-Condensation Methods To Prepare ZnO Films: Electron Transport Layers in Perovskite Solar Cells.

    Science.gov (United States)

    Zhao, Yu-Han; Zhang, Kai-Cheng; Wang, Zhao-Wei; Huang, Peng; Zhu, Kai; Li, Zhen-Dong; Li, Da-Hua; Yuan, Li-Gang; Zhou, Yi; Song, Bo

    2017-08-09

    Owing to the high charge mobility and low processing temperature, ZnO is regarded as an ideal candidate for electron transport layer (ETL) material in thin-film solar cells. For the film preparation, the presently dominated sol-gel (SG) and hydrolysis-condensation (HC) methods show great potential; however, the effect of these two methods on the performance of the resulting devices has not been investigated in the same frame. In this study, the ZnO films made through SG and HC methods were applied in perovskite solar cells (Pero-SCs), and the performances of corresponding devices were compared under parallel conditions. We found that the surface morphologies and the conductivities of the films prepared by SG and HC methods showed great differences. The HC-ZnO films with higher conductivity led to relatively higher device performance, and the best power conversion efficiencie (PCE) of 12.9% was obtained; meanwhile, for Pero-SCs based on SG-ZnO, the best PCE achieved was 10.9%. The better device performance of Pero-SCs based on HC-ZnO should be attributed to the better charge extraction and transportation ability of HC-ZnO film. Moreover, to further enhance the performance of Pero-SCs, a thin layer of pristine C 60 was introduced between HC-ZnO and perovskite layers. By doing so, the quality of perovskite films was improved, and the PCE was elevated to 14.1%. The preparation of HC-ZnO film involves relatively lower-temperature (maximum 100 °C) processing; the films showed better charge extraction and transportation properties and can be a more promising ETL material in Pero-SCs.

  20. Periodic nanostructures imprinted on high-temperature stable sol–gel films by ultraviolet-based nanoimprint lithography for photovoltaic and photonic applications

    Energy Technology Data Exchange (ETDEWEB)

    Back, Franziska [Schott AG, Research and Technology Development, Hattenbergstraße 10, 55122 Mainz (Germany); Fraunhofer-Institut für Silicatforschung ISC, Neunerplatz 2, 97082 Würzburg (Germany); Bockmeyer, Matthias; Rudigier-Voigt, Eveline [Schott AG, Research and Technology Development, Hattenbergstraße 10, 55122 Mainz (Germany); Löbmann, Peer [Fraunhofer-Institut für Silicatforschung ISC, Neunerplatz 2, 97082 Würzburg (Germany)

    2014-07-01

    Nanostructured sol–gel films with high-temperature stability are used in the area of electronics, photonics or biomimetic materials as light-trapping architectures in solar cells, displays, waveguides or as superhydrophobic surfaces with a lotus effect. In this work, high-temperature stable 2-μm nanostructured surfaces were prepared by ultraviolet-based nanoimprint lithography using an alkoxysilane binder incorporating modified silica nanoparticles. Material densification during thermal curing and microstructural evolution which are destined for a high structural fidelity of nanostructured films were investigated in relation to precursor chemistry, particle morphology and particle content of the imprint resist. The mechanism for densification and shrinkage of the films was clarified and correlated with the structural fidelity to explain the influence of the geometrical design on the optical properties. A high internal coherence of the microstructure of the nanostructured films results in a critical film thickness of > 5 μm. The structured glassy layers with high inorganic content show thermal stability up to 800 °C and have a high structural fidelity > 90% with an axial shrinkage of 16% and a horizontal shrinkage of 1%. This material allows the realization of highly effective light-trapping architectures for polycrystalline silicon thin-film solar cells on glass but also for the preparation of 2D photonic crystals for telecommunication wavelengths. - Highlights: • Fundamental research • Hybrid sol–gel material with high-temperature stability and contour accuracy • Ensuring of cost-efficient and industrially feasible processing • Application in photonic and photovoltaic.

  1. Characteristics and optical properties of iron ion (Fe{sup 3+})-doped titanium oxide thin films prepared by a sol-gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M.C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Lin, H.J. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)], E-mail: hjlin@nuu.edu.tw; Yang, T.S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2009-04-03

    Titanium dioxide (TiO{sub 2}) thin films doping of various iron ion (Fe{sup 3+}) concentrations have been prepared on a glass substrate by the sol-gel spin coating process. Characteristics and optical properties of TiO{sub 2} thin films doping of various Fe content were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis) and spectroscopic ellipsometry. The crystalline phase of TiO{sub 2} thin films comprised only the anatase TiO{sub 2}, but the crystallinity decreased when the Fe{sup 3+} content increased from 0 to 25.0 wt%. During the Fe{sup 3+} addition to 25.0 wt%, the phase of TiO{sub 2} thin film still maintained the amorphous state. The absorption edge of TiO{sub 2} thin films shifted towards longer wavelengths (i.e. red shifted) from 355 to 415 nm when the Fe{sup 3+}-doped concentration increased from 0 to 25.0 wt%. The values of the refractive index (n), and extinction coefficient (k), decreased with an increasing Fe{sup 3+} content. Moreover, the band-gap energy of TiO{sub 2} thin films also decreased from 3.29 to 2.83 eV with an increase in the Fe{sup 3+} content from 0 to 25.0 wt%.

  2. Thermochromic properties of W-doped VO2 thin films deposited by aqueous sol-gel method for adaptive infrared stealth application

    Science.gov (United States)

    Liu, Dongqing; Cheng, Haifeng; Xing, Xin; Zhang, Chaoyang; Zheng, Wenwei

    2016-07-01

    The W doped VO2 thin films with various W contents were successfully deposited by aqueous sol-gel method followed by a post annealing process. The derived thin films were characterized by X-ray diffraction, Raman spectra, scanning electron microscopy and atomic force microscopy. Besides, the resistance-temperature relationship and infrared emissivity in the waveband 7.5-14 μm were analyzed, and the effects of W doping on the thermochromic properties of VO2 thin films were studied. The results show that W atoms enter the crystal lattice of VO2 and the transition temperature decreases gradually with increasing doping amount of W. The emissivity of VO2-W-4% thin films has dropped to 0.4 when its real temperature is above 30 °C. The thermal infrared images were also examined under different temperature by thermal imager. The results indicate that the temperature under which W doped VO2 thin films begin to have lower emissivity decreases gradually with increasing doping amount of W. W doped VO2 thin films can control its infrared radiation intensity actively at a lower temperature level of 30 °C, which has great application prospects in the adaptive infrared stealth technology.

  3. Photoluminescence and ferroelectric properties of sol-gel-grown Eu-doped CaBi{sub 4}Ti{sub 4}O{sub 15} : Nd films

    Energy Technology Data Exchange (ETDEWEB)

    Wang Weichao; Zheng Haiwu; Liu Yuefeng; Li Zonghui; Zhang Ting; Zhang Weifeng [Key Laboratory of Photovoltaic Materials of Henan Province, Department of Physics, Institute of Physics for Microsystem, Henan University, Kaifeng 475004 (China)], E-mail: zhenghaiwu76@yahoo.com.cn, E-mail: wfzhang@henu.edu.cn

    2009-05-21

    Eu-doped CaBi{sub 4}Ti{sub 4}O{sub 15} : Nd (CBENT) ferroelectric thin films were prepared on Pt/Ti/SiO{sub 2}/Si substrates by a sol-gel method. The photoluminescence (PL) and ferroelectric properties of the films were investigated by using different annealing temperatures and concentrations of europium ions. All the CaBi{sub 3.75-x}Eu{sub x}Nd{sub 0.25}Ti{sub 4}O{sub 15} films have a polycrystalline bismuth-layered perovskite structure, and a morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was shown to exist. The PL intensity of the CBENT films is significantly dependent on annealing temperature and Eu concentration. The remanent polarization 2Pr values of the Eu-doped CaBi{sub 4}Ti{sub 4}O{sub 15} : Nd thin films reaches a maximum value of 30.7 {mu}C cm{sup -2} when x is 0.2. The PL and ferroelectric properties suggest that CBENT films can be considered as promising multifunctional materials.

  4. Photoluminescence and ferroelectric properties of sol-gel-grown Eu-doped CaBi4Ti4O15 : Nd films

    Science.gov (United States)

    Wang, Weichao; Zheng, Haiwu; Liu, Yuefeng; Li, Zonghui; Zhang, Ting; Zhang, Weifeng

    2009-05-01

    Eu-doped CaBi4Ti4O15 : Nd (CBENT) ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by a sol-gel method. The photoluminescence (PL) and ferroelectric properties of the films were investigated by using different annealing temperatures and concentrations of europium ions. All the CaBi3.75-xEuxNd0.25Ti4O15 films have a polycrystalline bismuth-layered perovskite structure, and a morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was shown to exist. The PL intensity of the CBENT films is significantly dependent on annealing temperature and Eu concentration. The remanent polarization 2Pr values of the Eu-doped CaBi4Ti4O15 : Nd thin films reaches a maximum value of 30.7 µC cm-2 when x is 0.2. The PL and ferroelectric properties suggest that CBENT films can be considered as promising multifunctional materials.

  5. Enhancing Optical and Electrical Properties of La- and Al-Codoped ZnO Thin Films Prepared by Sol-Gel Method -La Codoping Effect.

    Science.gov (United States)

    He-Yan, Hai

    2017-07-10

    Backgroud: The transparent conductive ZnO film is widely used in solar cell. Enhancing the transmittance and electrical conductivity of the films is attracting many attentions to improve cell efficiency. This work focuses on the fabrication and potential application of the various cation-doped ZnO materials in recent patents and literature and then presents the La codoping effects of Al-doped ZnO films. Films were deposited by a sol-gel route and characterized by various techniques including X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis and luminescent spectroscopies, and electrical conduction analysis. The UV-vis. transmittance and band gap increased and then decreased, whereas the resistivity decreased and then slightly increased with the increase in La/Al ratio. The La/Al ratio of 0.0105 led to a maximal transmittance, a widest band gap, and a minimal resistivity. The films also illustrated a near band gap emission and some intrinsic defect-related emissions with varied intensity with La/Al ratio. This work reveal that the electrical and optical properties of the ZnO:Al films can be well enhanced by La codoping. This is significant to the applications of the ZnO:Al materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Effect of compressive stress inducing a band gap narrowing on the photoinduced activities of sol-gel TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Ghazzal, Mohamed N., E-mail: mohamed.ghazzal@uclouvain.be [Laboratoire de Chimie et Methodologie pour l' Evironnement, Universite Paul Verlaine de Metz, rue Victor Demange, 57500 Saint-Avold (France); Institute of Condensed Matter and Nanoscience Molecules, Solids and reacTivity (IMCN/MOST), Universite catholique de Louvain, Croix du Sud 2/17, B-1348 Louvain-la-Neuve (Belgium); Chaoui, N. [Laboratoire de Spectrometrie de Masse et de Chimie Laser, Universite Paul Verlaine de Metz, Boulvard arago, F-57078 Metz Cedex 3 (France); Genet, M. [Institute of Condensed Matter and Nanoscience Molecules, Division of Bio and Soft Matter (IMCN/BSMA), Universite catholique de Louvain, Croix du Sud 2/17, B-1348 Louvain-la-Neuve (Belgium); Gaigneaux, Eric M. [Institute of Condensed Matter and Nanoscience Molecules, Solids and reacTivity (IMCN/MOST), Universite catholique de Louvain, Croix du Sud 2/17, B-1348 Louvain-la-Neuve (Belgium); Robert, D. [Laboratoire des Materiaux, Surface et Procedes pour la Catalyse (LMSPC) CNRS-UMR7515, Antenne de Saint-Avold, UPV-Metz, Rue Victor Demange 57500 Saint-Avold (France)

    2011-11-30

    TiO{sub 2} thin films grown on different kinds of substrates were obtained by sol-gel process. X-ray diffraction revealed that the TiO{sub 2} lattice parameter c decreased continuously, indicating a continuous variation in the compressive stress, a negligible compressive stress of the film grown onto Soda-Lime Glass (SLG), medium compressive stress of the film grown onto BoroSilicate Glass (BSG) and large compressive stress of the film deposited onto the Quartz Substrate (QS). UV-Vis absorbance spectra exhibited a red-shift of the absorbance edge of the TiO{sub 2} films suggesting a lowering of the band gap, which is a direct consequence of the increase of the compressive stress. X-ray photoelectron spectroscopy revealed that the surface composition of titania films was similar except for sodium-ion concentration. The rate observed during the photo-oxydation of the stearic acid on TiO{sub 2}/QS was twice as high as that of TiO{sub 2}/BSG and about 1000 times superior to that of TiO{sub 2}/SLG. The photoinduced wettability shows an identical dependence of the compressive stress. According to these results, the compressive stress could be used to tune the band gap of the titanium oxide in order to enhance the photoinduced properties.

  7. Room Temperature Tunable Multiferroic Properties in Sol-Gel-Derived Nanocrystalline Sr(Ti1-xFex)O3-δThin Films.

    Science.gov (United States)

    Wang, Yi-Guang; Tang, Xin-Gui; Liu, Qiu-Xiang; Jiang, Yan-Ping; Jiang, Li-Li

    2017-09-08

    Sr(Ti 1- x Fe x )O 3-δ (0 ≤ x ≤ 0.2) thin films were grown on Si(100) substrates with LaNiO₃ buffer-layer by a sol-gel process. Influence of Fe substitution concentration on the structural, ferroelectric, and magnetic properties, as well as the leakage current behaviors of the Sr(Ti 1- x Fe x )O 3-δ thin films, were investigated by using the X-ray diffractometer (XRD), atomic force microscopy (AFM), the ferroelectric test system, and the vibrating sample magnetometer (VSM). After substituting a small amount of Ti ion with Fe, highly enhanced ferroelectric properties were obtained successfully in SrTi 0.9 Ti 0.1 O 3-δ thin films, with a double remanent polarization (2 P r ) of 1.56, 1.95, and 9.14 μC·cm -2 , respectively, for the samples were annealed in air, oxygen, and nitrogen atmospheres. The leakage current densities of the Fe-doped SrTiO₃ thin films are about 10 -6 -10 -5 A·cm -2 at an applied electric field of 100 kV·cm -1 , and the conduction mechanism of the thin film capacitors with various Fe concentrations has been analyzed. The ferromagnetic properties of the Sr(Ti 1- x Fe x )O 3-δ thin films have been investigated, which can be correlated to the mixed valence ions and the effects of the grain boundary. The present results revealed the multiferroic nature of the Sr(Ti 1- x Fe x )O 3-δ thin films. The effect of the annealing environment on the room temperature magnetic and ferroelectric properties of Sr(Ti 0.9 Fe 0.1 )O 3-δ thin films were also discussed in detail.

  8. Aluminum-doped zinc oxide sol–gel thin films: Influence of the sol's water content on the resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Nehmann, Julia B., E-mail: nehmann@isfh.de [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Ehrmann, Nicole; Reineke-Koch, Rolf [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Bahnemann, Detlef W. [Institute for Technical Chemistry, Gottfried Wilhelm Leibniz University Hannover, Callinstrasse 3A, 30167 Hannover (Germany)

    2014-04-01

    Thin films of indium tin oxide (ITO) have gained substantial interest due to their optical and electrical properties. Since ITO is an expensive material and indium is a rare element, considerable attempts have been made to replace it by, e.g., aluminum-doped zinc oxide (ZnO:Al). The production of ZnO:Al is less cost-intensive, especially if the sol–gel technique is applied, while its properties are comparable to those of ITO. In this study, we demonstrate that the electrical properties of ZnO:Al thin films can be improved considerably by the addition of small amounts of ultrapure water to the dip coating solution during the preparation. The lowest resistivity obtained with a film prepared from a sol containing 0.2 M water is 2.8·10{sup −3Ω}cm. Optical modeling thus indicates an improvement of the free carrier mobility of films prepared from sols in the presence of additional water. The films prepared have an average thickness of 340 nm and a solar transmittance above 85% after annealing in a forming gas atmosphere. Clearly, the addition of water to the sol has a positive impact on the resistivity of the final ZnO:Al thin film. We suggest the observed increase of the free carrier mobility to be due to an improved electron transfer at the grain boundaries between the spherical nanoparticles. - Highlights: • We prepared ZnO:Al thin films with additional water in the sol by dip coating. • We found a positive impact of the water in the sol on the resistivity of the film. • The free carrier concentration and mobility increased with additional 0.2 M water. • The refractive indices demonstrate a denser structure related to the water content.

  9. Room Temperature Tunable Multiferroic Properties in Sol-Gel-Derived Nanocrystalline Sr(Ti1−xFexO3−δ Thin Films

    Directory of Open Access Journals (Sweden)

    Yi-Guang Wang

    2017-09-01

    Full Text Available Sr(Ti1−xFexO3−δ (0 ≤ x ≤ 0.2 thin films were grown on Si(100 substrates with LaNiO3 buffer-layer by a sol-gel process. Influence of Fe substitution concentration on the structural, ferroelectric, and magnetic properties, as well as the leakage current behaviors of the Sr(Ti1−xFexO3−δ thin films, were investigated by using the X-ray diffractometer (XRD, atomic force microscopy (AFM, the ferroelectric test system, and the vibrating sample magnetometer (VSM. After substituting a small amount of Ti ion with Fe, highly enhanced ferroelectric properties were obtained successfully in SrTi0.9Ti0.1O3−δ thin films, with a double remanent polarization (2Pr of 1.56, 1.95, and 9.14 μC·cm−2, respectively, for the samples were annealed in air, oxygen, and nitrogen atmospheres. The leakage current densities of the Fe-doped SrTiO3 thin films are about 10−6–10−5 A·cm−2 at an applied electric field of 100 kV·cm−1, and the conduction mechanism of the thin film capacitors with various Fe concentrations has been analyzed. The ferromagnetic properties of the Sr(Ti1−xFexO3−δ thin films have been investigated, which can be correlated to the mixed valence ions and the effects of the grain boundary. The present results revealed the multiferroic nature of the Sr(Ti1−xFexO3−δ thin films. The effect of the annealing environment on the room temperature magnetic and ferroelectric properties of Sr(Ti0.9Fe0.1O3−δ thin films were also discussed in detail.

  10. Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

    Directory of Open Access Journals (Sweden)

    Carlos Gumiel

    2018-01-01

    Full Text Available Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600 °C.

  11. Structural Modification of Sol-Gel Synthesized V2O5 and TiO2 Thin Films with/without Erbium Doping

    Directory of Open Access Journals (Sweden)

    Fatma Pınar Gökdemir

    2014-01-01

    Full Text Available Comparative work of with/without erbium- (Er- doped vanadium pentoxide (V2O5 and titanium dioxide (TiO2 thin films were carried out via sol-gel technique by dissolving erbium (III nitrate pentahydrate (Er(NO33·5H2O in vanadium (V oxoisopropoxide (OV[OCH(CH32]3 and titanium (IV isopropoxide (Ti[OCH(CH32]4. Effect of Er doping was traced by Fourier transform IR (FTIR, thermogravimetric/differential thermal (TG/DTA, and photoluminescence measurements. UV-Vis transmission/absorption measurement indicated a blue shift upon Er doping in V2O5 film due to the softening of V=O bond while appearance of typical absorption peaks in Er-doped TiO2 film. Granule size of the films increased (reduced upon Er substitution on host material compared to undoped V2O5 and TiO2 films, respectively.

  12. CdO thin films based on the annealing temperature differences prepared by sol–gel method and their heterojunction devices

    Science.gov (United States)

    Soylu, M.; Yazici, T.

    2017-12-01

    Undoped CdO films were prepared on glass substrate and p-type silicon wafer using sol–gel spin coating method. The structural and optical properties of the films were investigated as a function of the annealing temperature. X-ray diffraction (XRD) patterns reveal that the films are formed from CdO with cubic crystal structure and (1 1 1) preferred orientation. It is seen that good crystallinity is due to the high annealing temperature. The surface morphology of the CdO films was found to be depending on the annealing temperature, showing cauliflower like structure. Optical band gaps for annealing temperature of 250 °C and 450 °C were found to be 2.49 eV and 2.27 eV, respectively, showing a decrease with raising temperature. Optics parameters such as extinction coefficient, refractive index, and surface-volume energy loss were determined with spectrophotometric analysis as a function of annealing temperature. CdO/p-Si heterojunction structure showed weak rectifying behavior. The diode parameters were found to be depending on annealing temperature. The results are encouraging to get better conjunction with CdO thin film component at optimize annealing temperature.

  13. Up-conversion emission in rare earth-doped Y{sub 2}Ti{sub 2}O{sub 7} sol-gel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jenouvrier, P. [Institut de Microelectronique, Electromagnetisme et Photonique, UMR 5130, INPG-UJF-CNRS, ENSERG, BP 257, 38016 Grenoble (France); Laboratoire des Materiaux et du Genie Physique, UMR 5628, INPG-CNRS, ENSPG, BP 46, Domaine Universitaire, Rue de la Houille-Blanche, 38402 Saint Martin d' Heres, Cedex (France); Boccardi, G. [Laboratoire des Materiaux et du Genie Physique, UMR 5628, INPG-CNRS, ENSPG, BP 46, Domaine Universitaire, Rue de la Houille-Blanche, 38402 Saint Martin d' Heres, Cedex (France); Fick, J. [Laboratoire de Spectrometrie Physique, UMR 5588, Universite Joseph Fourier-CNRS, BP 87, 38402 Saint Martin d' Heres (France); Jurdyc, A.-M. [Laboratoire de Physico-Chimie des Materiaux Luminescents, UMR 5620, CNRS-UCBL, 69622 Villeurbanne (France); Langlet, M. [Laboratoire des Materiaux et du Genie Physique, UMR 5628, INPG-CNRS, ENSPG, BP 46, Domaine Universitaire, Rue de la Houille-Blanche, 38402 Saint Martin d' Heres, Cedex (France)]. E-mail: michel.langlet@inpg.fr

    2005-06-15

    Yttrium titanate (YTO) thin films doped with rare earth elements have been deposited using the aerosol-gel process. The up-conversion emission (UPE) of films doped with erbium and/or thulium has been studied with respect to the film crystallization degree and rare earth concentration. The effects of ytterbium codoping have been considered as well. Mechanisms that control UPE of YTO films are discussed with respect to the experimental conditions. It is shown that films, which selectively emit in the blue ({sup 1}G{sub 4}{yields}{sup 3}H{sub 6} transition of thulium ions), green ({sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2} and {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2} transitions of erbium ions), or red ({sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2} transition of erbium ions), can readily be achieved.

  14. Effect of Sn-doped on microstructural and optical properties of ZnO thin films deposited by sol-gel method

    International Nuclear Information System (INIS)

    Tsay, C.-Y.; Cheng, H.-C.; Tung, Y.-T.; Tuan, W.-H.; Lin, C.-K.

    2008-01-01

    In this study, transparent thin films of Sn-doped ZnO (ZnO:Sn) were deposited onto alkali-free glass substrates by a sol-gel method; the effect of Sn doping on crystallinity, microstructural and optical properties was investigated. The atomic percentages of dopant in ZnO-based sols were Sn/Zn = 0, 1, 2, 3, and 5 at.%. The as-deposited films were pre-heated at 300 deg. C for 10 min and then annealed in air at 500 deg. C for 1 h. The results show that Sn-doped ZnO thin films demonstrate obviously improved surface roughness, enhanced transmittance in the 400-600 nm wavelength range and reduced average crystallite size. Among all of the annealed ZnO-based films in this study, films doped with 2 at.% Sn concentration exhibited the best properties, namely an average transmittance of 90%, an RMS roughness value of 1.92 nm and a resistivity of 9.3 x 10 2 Ω-cm

  15. Effect of annealing temperature on structural, morphological and electrical properties of nanoparticles TiO{sub 2} thin films by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Muaz, A. K. M.; Hashim, U., E-mail: uda@unimap.edu.my; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L. [Institute of Nano Electronic Engineering, Univerisiti Malaysia Perlis, 01000 Kangar, Perlis (Malaysia)

    2016-07-06

    In this paper, the sol-gel method is used to prepare nanoparticles titanium dioxide (TiO{sub 2}) thin films at different annealing temperature. The prepared sol was deposited on the p-SiO{sub 2} substrates by spin coating technique under room temperature. The nanoparticles TiO{sub 2} solution was synthesized using Ti{OCH(CH_3)_2}{sub 4} as a precursor with an methanol solution at a molar ratio 1:10. The prepared TiO{sub 2} sols will further validate through structural, morphological and electrical properties. From the X-ray diffraction (XRD) analysis, as-deposited films was found to be amorphous in nature and tend to transform into tetragonal anatase and rutile phase as the films annealed at 573 and 773 K, respectively. The diversification of the surface roughness was characterized by atomic force microscopy (AFM) indicated the roughness and thickness very dependent on the annealing temperature. The two-point probe electrical resistance and conductance of nanoparticles TiO{sub 2} thin films were determined by the DC current-voltage (IV) analysis. From the I-V measurement, the electrical conductance increased as the films annealed at higher temperature.

  16. Preparation and optical properties of mesoporous TiO2 thin films by a two-step sol-gel technique

    International Nuclear Information System (INIS)

    Kartini, I.; Lu, G.Q.; Meredith, P.; Zhao, X.S.

    2002-01-01

    This paper concerns the preparation of mesoporous titania nanopowders and thin films for use in next generation photoelectrochemical solar cells. We have recently developed a novel method for preparing mesoporous TiO 2 powders using a Two-Step Sol-gel method (TSS). These materials have crystalline domains characteristic of anatase. The first step of the process involves the hydrolysis of titanium isopropoxide in a basic aqueous solution mediated by neutral surfactant. The solid product resulting from Step-1 is then treated in acidified ethanol solution containing a titanium precursor to yield anatase TiO 2 . The resultant powder exhibits a high surface area and large pore volume with uniform mesopores. Slurries made from the resultant powder of Steps 1 and 2 have been used to produce thin titania films on glass slides. The optical and structural properties of these films have been compared to the films made of a commercial titania (Degussa P25, BASF). We will discuss these properties with respect to the possible use of such mesoporous titania films as the wide band gap semiconductor in dye-sensitized nanocrystalline TiO 2 solar cells

  17. Fabrication of the heterojunction diode from Y-doped ZnO thin films on p-Si substrates by sol-gel method

    Science.gov (United States)

    Sharma, Sanjeev K.; Singh, Satendra Pal; Kim, Deuk Young

    2018-02-01

    The heterojunction diode of yttrium-doped ZnO (YZO) thin films was fabricated on p-Si(100) substrates by sol-gel method. The post-annealing process was performed at 600 °C in vacuum for a short time (3 min) to prevent inter-diffusion of Zn, Y, and Si atoms. X-ray diffraction (XRD) pattern of as-grown and annealed (600 °C in vacuum) films showed the preferred orientation along the c-axis (002) regardless of dopant concentrations. The uniform surface microstructure and the absence of other metal/oxide peaks in XRD pattern confirmed the excellence of films. The increasing bandgap and carrier concentration of YZO thin films were interpreted by the BM shift, that is, the Fermi level moves towards the conduction band edge. The current-voltage characteristics of the heterojunction diode, In/n-ZnO/p-Si/Al, showed a rectification behavior. The turn-on voltage and ideality factor of n-ZnO/p-Si and n-YZO/p-Si were observed to be 3.47 V, 2.61 V, and 1.97, 1.89, respectively. Y-dopant in ZnO thin films provided more donor electrons caused the shifting of Fermi-energy level towards the conduction band and strengthen the interest for heterojunction diodes.

  18. Surface characterisation and photocatalytic performance of N-doped TiO2 thin films deposited onto 200 nm pore size alumina membranes by sol–gel methods

    International Nuclear Information System (INIS)

    Grilli, R.; Di Camillo, D.; Lozzi, L.; Horovitz, I.; Mamane, H.; Avisar, D.; Baker, M.A.

    2015-01-01

    Membrane filtration is employed for water treatment and wastewater reclamation purposes, but membranes alone are unable to remove pollutant molecules and certain pathogens. Photocatalytically active N-doped TiO 2 coatings have been deposited by sol–gel onto 200 nm pore size alumina membranes for water treatment applications using two different methods, via pipette droplets or spiral bar applicator. The uncoated and coated membranes were characterised by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectrometry (EDX). Both coatings showed the presence of N-doped anatase, with a surface coverage between 84 and 92%, and nitrogen concentration (predominantly interstitial) of 0.9 at.%. The spiral bar applicator deposited coatings exhibit a thicker mud-cracked surface layer with limited penetration of the porous membrane, whilst the pipette deposited coatings have mostly penetrated into the bulk of the membrane and a thinner layer is present at the surface. The photocatalytic activity (PCA), measured through the degradation of carbamazepine (CBZ), under irradiation of a solar simulator was 58.6% for the pipette coating and 63.3% for the spiral bar coating. These photocatalytically active N-doped sol–gel coated membranes offer strong potential in forming the fundamental basis of a sunlight based water treatment system. - Highlights: • Sol gel N-doped TiO 2 thin films were deposited on 200 nm pore size Al 2 O 3 membranes. • Two sol–gel methods have been compared – pipette drop and spiral bar deposition. • The coatings showed a similar microstructure and composition but different morphology. • The PCA (degradation of carbamazepine) was ∼60% for both sol–gel coatings. • The coated membranes are promising for use in a membrane based water treatment system

  19. Structure and electrical properties of Na0.5Bi0.5TiO3 ferroelectric thick films derived from a polymer modified sol-gel method.

    Science.gov (United States)

    Ji, Hongfen; Ren, Wei; Wang, Lingyan; Shi, Peng; Chen, Xiaofeng; Wu, Xiaoqing; Yao, Xi; Lau, Sien-Ting; Zhou, Qifa; Shung, K Kirk

    2011-10-01

    Lead-free NaBi(0.5)TiO(3) (NBT) ferroelectric thick films were prepared by a poly(vinylpyrrolidone) (PVP) modified sol-gel method. The NBT thick films annealed from 500°C to 750°C exhibit a perovskite structure. The relationship between annealing temperature, thickness, and electrical properties of the thick films has been investigated. The dielectric constants and remnant polarizations of the thick films increase with annealing temperature. The electrical properties of the NBT films show strong thickness dependence. As thickness increases from 1.0 to 4.8 μm, the dielectric constant of the NBT films increases from 620 to 848, whereas the dielectric loss is nearly independent of the thickness. The remnant polarization of the NBT thick films also increases with increasing thickness. The leakage current density first decreases and then increases with film thickness.

  20. Bipolar and unipolar resistive switching behaviors of sol–gel-derived SrTiO3 thin films with different compliance currents

    International Nuclear Information System (INIS)

    Tang, M H; Wang, Z P; Zeng, Z Q; Xu, X L; Wang, G Y; Zhang, L B; Xiao, Y G; Yang, S B; Jiang, B; Li, J C; He, J

    2011-01-01

    The SrTiO 3 (STO) thin films on a Pt/Ti/SiO 2 /Si substrate were synthesized using a sol–gel method to form a metal–insulator–metal structure. This device shows the bipolar resistance switching (BRS) behavior for a compliance current I cc of less than 0.1 mA but exhibits soft breakdown at a higher level of compliance current. A transition from the BRS behavior to the stable unipolar resistive switching behavior (URS) was also observed. We found that the BRS behavior may be controlled by the structure interface while the URS behavior is likely bulk controlled. Our study indicates that the external compliance current is a key factor in resistance switching phenomenon of STO thin films

  1. Fabrication of Cost-Effective Dye-Sensitized Solar Cells Using Sheet-Like CoS2 Films and Phthaloylchitosan-Based Gel-Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Saradh Prasad

    2018-01-01

    Full Text Available Platinum-free counter electrodes (CE were developed for use in efficient and cost-effective energy conversion devices, such as dye-sensitized solar cells (DSSCs. Electrochemical deposition of CoS2 on fluorine-doped tin oxide (FTO formed a hierarchical sheet-like structured CoS2 thin film. This film was engaged as a cost-effective platinum-free and high-efficiency CE for DSSCs. High stability was achieved using a phthaloychitosan-based gel-polymer electrolyte as the redox electrolyte. The electrocatalytic performance of the sheet-like CoS2 film was analyzed by electrochemical impedance spectroscopy and cyclic voltammetry. The film displayed improved electrocatalytic behavior that can be credited to a low charge-transfer resistance at the CE/electrolyte boundary and improved exchange between triiodide and iodide ions. The fabricated DSSCs with a phthaloychitosan-based gel-polymer electrolyte and sheet-like CoS2 CE had a power conversion efficiency (PCE, η of 7.29% with a fill factor (FF of 0.64, Jsc of 17.51 mA/cm2, and a Voc of 0.65 V, which was analogous to that of Pt CE (η = 7.82%. The high PCE of the sheet-like CoS2 CE arises from the enhanced FF and Jsc, which can be attributed to the abundant active electrocatalytic sites and enhanced interfacial charge-transfer by the well-organized surface structure.

  2. Structural, optical and NO{sub 2} gas sensing properties of ZnMgO thin films prepared by the sol gel method

    Energy Technology Data Exchange (ETDEWEB)

    Chebil, W., E-mail: chbil.widad@live.fr [Unité de Service Commun de Recherche « High resolution X-ray diffractometer », Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019, Monastir (Tunisia); Laboratoire Physico-chimie des Matériaux, Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l' environnement, 5019 Monastir (Tunisia); Boukadhaba, M.A. [Unité de Service Commun de Recherche « High resolution X-ray diffractometer », Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019, Monastir (Tunisia); Laboratoire Physico-chimie des Matériaux, Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l' environnement, 5019 Monastir (Tunisia); Madhi, I. [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, BP 95, 2050, Hammam-Lif (Tunisia); and others

    2017-01-15

    In this present work, ZnO and ZnMgO thin films prepared by a sol-gel process were deposited on glass substrates via spin coating technique. The structural, morphological and optical properties of the obtained films were investigated. X-ray diffraction study revealed that all layers exhibit a hexagonal wurtzite structure without any secondary phase segregation. The atomic force microscopy (AFM) depicts that the grains size of ours samples decreases as magnesium content increases. The absorption spectra obtained on ZnMgO thin films show a band gap tuning from 3.19 to 3.36 eV, which is also consistent with blue shifting of near-band edge PL emission, measured at low temperature. The incorporated amount of magnesium was calculated and confirmed by EDX. The gas sensing performances were tested in air containing NO{sub 2} for different operating temperatures. The experimental result exhibited that ZnMgO sensors shows a faster response and recovery time than the ZnO thin films. The resistivity and the sensor response as function of Mg content were also investigated.

  3. Far-infrared properties of sol-gel derived PbZr0.52Ti0.48O3 thin films on Pt-coated substrates

    International Nuclear Information System (INIS)

    Kafadaryan, E A; Hovsepyan, R K; Khachaturova, A A; Aghamalyan, N R; Shirinyan, G O; Manukyan, A L; Vardanyan, R S; Hayrapetyan, A G; Grigoryan, S G; Vardanyan, E S

    2003-01-01

    Polycrystalline tetragonal PbZr 0.52 Ti 0.48 O 3 (PZT) thin films have been deposited on the nickel and (111) platinum coated (110) sapphire substrates by the sol-gel method. Optical properties of the PZT thin films were studied using far-infrared reflectivity spectroscopy in the 200-10 000 cm -1 frequency range at 300 K. The frequency dependence of the optical characteristics (σ, ε, -Im ε -1 ) of the films were calculated by the Kramers-Kronig transformation of the reflectivity spectra and analysed by the Drude-Lorentz model. The frequency dependence of the optical conductivity, σ(ω), of the PZT films deposited on platinum coated sapphire is well described by the free-carrier term and an overdamped mid-infrared component. Sapphire/Pt/PZT structures reveal semiconductor properties (effective carrier concentration N/m* is up to 10 20 cm -3 , plasma minimum is located near 3000 cm -1 ). This effect can be related to the favourable influence of the platinum electrode on the charge carrier density at Pt/PZT contact and formation of the interfacial conductive layer

  4. High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode

    Science.gov (United States)

    Mei, Xiaoguang; Cho, Swee Jen; Fan, Benhu; Ouyang, Jianyong

    2010-10-01

    High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

  5. High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode

    International Nuclear Information System (INIS)

    Mei Xiaoguang; Cho, Swee Jen; Fan Benhu; Ouyang Jianyong

    2010-01-01

    High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

  6. Ferroelectric domains and phase transition of sol-gel processed epitaxial Sm-doped BiFeO3 (001 thin films

    Directory of Open Access Journals (Sweden)

    Zhen Zhou

    2018-03-01

    Full Text Available BiFeO3, a room-temperature multiferroic material, has recently been increasingly applied as a potential lead-free piezoelectric material due to its large piezoelectricity achieved by doping. In this work, 12% Sm-doped BiFeO3 epitaxial thin films were fabricated on Nb-doped SrTiO3 (001 single crystal substrates via sol-gel method. The epitaxy was verified by reciprocal space mapping (RSM and transmission electron microscope (TEM. The TEM results indicated the coexistence of R3c and Pbam phases in the film. The domains and piezoelectric properties from room temperature to 200 °C were characterized by piezoresponse force microscopy (PFM. Domains became active from 110 °C to 170 °C, and domain configurations changed obviously. A partially fading piezoresponse indicated the emergence of antiferroelectric Pbam. The in-situ domain analysis suggested that the phase transition was accompanied by domain wall motion. Switching spectroscopy PFM (SS-PFM was further conducted to investigate the piezoresponse during the phase transition. Anomalous responses were found in both ON and OFF states at 170 °C, and the film exhibits typical antiferroelectric behavior at 200 °C, implying that the completion of phase transition and structure turned to the Pbam phase. This work revealed the origin of the high piezoresponse of Sm-doped BiFeO3 thin films at the morphotropic phase boundary (MPB.

  7. Effect of Annealing Temperature on Structural, Optical, and Electrical Properties of Sol-Gel Spin-Coating-Derived Cu2ZnSnS4 Thin Films

    Science.gov (United States)

    Hosseinpour, Rabie; Izadifard, Morteza; Ghazi, Mohammad Ebrahim; Bahramian, Bahram

    2018-02-01

    The effect of annealing temperature on structural, optical, and electrical properties of Cu2ZnSnS4 (CZTS) thin films grown on a glass substrate by spin coating sol-gel technique has been studied. Structural study showed that all samples had kesterite crystalline structure. Scanning electron microscopy images showed that the crystalline quality of the samples was improved by heat treatment. Optical study showed that the energy gap values for the samples ranged from 1.55 eV to 1.78 eV. Moreover, good optical conductivity values (1012 S-1 to 1014 S-1) were obtained for the samples. Investigation of the electrical properties of the CZTS thin films showed that the carrier concentration increased significantly with the annealing temperature. The photoelectrical behavior of the samples revealed that the photocurrent under light illumination increased significantly. Overall, the results show that the CZTS thin films annealed at 500°C had better structural, optical, and electrical properties and that such CZTS thin films are desirable for use as absorber layers in solar cells. The photovoltaic properties of the CZTS layer annealed at 500°C were also investigated and the associated figure of merit calculated. The results showed that the fabricated ZnS-CZTS heterojunction exhibited good rectifying behavior but rather low fill factor.

  8. Fabrication and electrical resistivity of Mo-doped VO2 thin films coated on graphite conductive plates by a sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Choi, W.; Jung, H.M.; Um, S. [Hanyang Univ., Seoul (Korea, Republic of). School of Mechanical Engineering

    2008-07-01

    Vanadium oxides (VO2) can be used in optical devices, thermochromic smart windows and sensors. This paper reported on a study in which vanadium pentoxide (V2O5) powder was prepared and mixed with Molybdenum Oxides (MoO3) to form Mo-doped and -undoped VO2 thin films by a sol-gel method on graphite conductive substrates. The micro-structure and chemical compositions of the Mo-doped and -undoped VO2 thin films was investigated using X-Ray diffraction and scanning electron microscopy. Changes in electrical resistivity were measured as a function of the stoichiometric compositions between vanadium and molybdenum. In this study. Mo-doped and -undoped VO2 thin films showed the typical metal to insulator transition (MIT), where temperature range could be adjusted by modifying the dopant atomic ratio. The through-plane substrate structure of the Mo-doped layer influences the electrical resistivity of the graphite substrate. As the amount of the molybdenum increases, the electrical resistivity of the graphite conductive substrate decreases in the lower temperature range below the freezing point of water. The experimental results showed that if carefully controlled, thermal dissipation of VO2 thin films can be used as a self-heating source to melt frozen water with the electrical current flowing through the graphite substrate. 3 refs., 3 figs.

  9. Structural, magnetic and optical properties of Ni-doped TiO2 thin films deposited on silicon(1 0 0) substrates by sol–gel process

    International Nuclear Information System (INIS)

    Tian, Jianjun; Gao, Huiping; Deng, Hongmei; Sun, Lin; Kong, Hui; Yang, Pingxiong; Chu, Junhao

    2013-01-01

    Highlights: •Ni doping decreases the activation energy for the anatase-to-rutile transformation. •With increasing Ni content, the reversible ferromagnetism is found. •Sharp decrease of the E OBG at low Ni content is mainly related to phase composition. -- Abstract: Ni-doped TiO 2 films were deposited on Si(1 0 0) substrates by sol–gel technique. X-ray photoelectron spectroscopy analysis suggests that the valence of Ni ion is in +2 and oxygen vacancies increase with increasing Ni content. X-ray diffraction measurements indicate that Ni doping catalyzes the anatase-to-rutile transformation (ART) of TiO 2 films, which is due to the decrease of the ART activation energy. The reversible ferromagnetism of the samples with Ni fraction is found, which is due to an anatase-to-rutile junction destroying an F-center bound magnetic polaron. Optical properties of Ni-doped TiO 2 films were studied by the ellipsometric spectra. With increasing Ni content, the optical band gap of TiO 2 films is decreased from 3.56 to 3.34 eV, which may be related to phase composition and impurity band

  10. Uniform thin films of CdSe and CdSe(ZnS) core(shell) quantum dots by sol-gel assembly: enabling photoelectrochemical characterization and electronic applications.

    Science.gov (United States)

    Korala, Lasantha; Wang, Zhijie; Liu, Yi; Maldonado, Stephen; Brock, Stephanie L

    2013-02-26

    Optoelectronic properties of quantum dot (QD) films are limited by (1) poor interfacial chemistry and (2) nonradiative recombination due to surface traps. To address these performance issues, sol-gel methods are applied to fabricate thin films of CdSe and core(shell) CdSe(ZnS) QDs. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging with chemical analysis confirms that the surface of the QDs in the sol-gel thin films are chalcogen-rich, consistent with an oxidative-induced gelation mechanism in which connectivity is achieved by formation of dichalcogenide covalent linkages between particles. The ligand removal and assembly process is probed by thermogravimetric, spectroscopic, and microscopic studies. Further enhancement of interparticle coupling via mild thermal annealing, which removes residual ligands and reinforces QD connectivity, results in QD sol-gel thin films with superior charge transport properties, as shown by a dramatic enhancement of electrochemical photocurrent under white light illumination relative to thin films composed of ligand-capped QDs. A more than 2-fold enhancement in photocurrent, and a further increase in photovoltage can be achieved by passivation of surface defects via overcoating with a thin ZnS shell. The ability to tune interfacial and surface characteristics for the optimization of photophysical properties suggests that the sol-gel approach may enable formation of QD thin films suitable for a range of optoelectronic applications.

  11. Uniform Thin Films of CdSe and CdSe(ZnS) Core(shell) Quantum Dots by Sol-Gel Assembly: Enabling Photoelectrochemical Characterization and Electronic Applications

    Science.gov (United States)

    Korala, Lasantha; Wang, Zhijie; Liu, Yi; Maldonado, Stephen; Brock, Stephanie L.

    2013-01-01

    Optoelectronic properties of quantum dot (QD) films are limited by (1) poor interfacial chemistry and (2) non-radiative recombination due to surface traps. To address these performance issues, sol-gel methods are applied to fabricate thin films of CdSe and core(shell) CdSe(ZnS) QDs. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging with chemical analysis confirms that the surface of the QDs in the sol-gel thin films are chalcogen-rich, consistent with an oxidative-induced gelation mechanism in which connectivity is achieved by formation of dichalcogenide covalent linkages between particles. The ligand removal and assembly process is probed by thermogravimetric, spectroscopic and microscopic studies. Further enhancement of inter-particle coupling via mild thermal annealing, which removes residual ligands and reinforces QD connectivity, results in QD sol-gel thin films with superior charge transport properties, as shown by a dramatic enhancement of electrochemical photocurrent under white light illumination relative to thin films composed of ligand-capped QDs. A more than 2-fold enhancement in photocurrent, and a further increase in photovoltage can be achieved by passivation of surface defects via overcoating with a thin ZnS shell. The ability to tune interfacial and surface characteristics for the optimization of photophysical properties suggests that the sol-gel approach may enable formation of QD thin films suitable for a range of optoelectronic applications. PMID:23350924

  12. Structure, morphology and optical behavior of Ni1-xCoxO thin films prepared by a modified sol-gel method

    Science.gov (United States)

    Alshahrie, Ahmed

    2016-08-01

    Nanocrystalline Ni1-xCoxO thin films (0 ≤ x ≤ 0.4) have been prepared on glass substrates using sol-gel/spin-coating technique. The effect of the concentration of cobalt ions on the structure, morphology and optical behavior of the doped NiO thin films are investigated by the X-ray diffractometer, scanning electron microscopy, Raman spectroscopy and spectrophotometer. All films showed a single phase face centered cubic structure, implying the complete solubility of the Co ions into the NiO cubic crystal up to 40 at.%, for the first time. The texture coefficient revealed that the Co ions tend to force the NiO grains to grow along (200) direction. The Raman spectroscopy showed one longitudinal optical phonon mode (LO) at 518 cm-1 and two longitudinal optical phonons mode (2LO) at 1070 cm-1. The decrease of the intensity and the shift of the peak position of the two modes, indicating the scattering contribution of the LO-mode outside the center of Brillouin zone and the creation of oxygen vacancies due to the incorporated Co ions into the NiO cubic crystals. The Ni1-xCoxO thin films have shown high optical transparency around 80%. A decrease of the band gap energy of the NiO films from 3.69 eV to 3.41 eV was observed when the concentration of Co ions increased to 10 at.%, followed by an increase to 3.58 eV as the Co ions concentration increased to 40 at.%. The high optical conductivity and low dissipation factor of the developed Ni1-xCoxO thin films will open a new avenue for future applications in the optoelectronic devices such as reflectance mirror and display light shutter.

  13. Sol-gel synthesis, characterization and optical properties of mercury-doped TiO{sub 2} thin films deposited on ITO glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mechiakh, R., E-mail: raouf_mechiakh@yahoo.fr [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP 95, Hammam-Lif 2050 (Tunisia); Ben Sedrine, N.; Chtourou, R. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP 95, Hammam-Lif 2050 (Tunisia)

    2011-08-15

    The Hg-doped and undoped nano-crystalline TiO{sub 2} films on ITO glass substrates surface and polycrystalline powders were prepared by sol-gel dip coating technique. The crystal structure and surface morphology of TiO{sub 2} were characterized by means of X-ray diffractometer (XRD), atomic force microscope (AFM), spectrophotometer, Fourier-transform infrared (FTIR), and spectroscopic ellipsometry (SE). The results indicated that the powder of TiO{sub 2}, doped with 5% Hg in room temperature was only composed of the anatase phase whereas in the undoped powder exhibits an amorphous phase were present. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 400 {sup o}C. The average crystallite size of the undoped TiO{sub 2} films was about 8.17 nm and was increased with Hg-doping in the TiO{sub 2} films. Moreover, the grains distributed more uniform and the surface roughness was greater in the Hg-doped TiO{sub 2} films than in the undoped one. Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range (1.95-2.49) and the porosity is in the range (47-2.8). The coefficient of transmission varies from 60 to 90%. SE study was used to determine the annealing temperature effect on the optical properties in the wavelength range from 0.25 to 2 {mu}m and the optical gap of the Hg-doped TiO{sub 2} thin films.

  14. Titanium dioxide–gold nanocomposite materials embedded in silicate sol–gel film catalyst for simultaneous photodegradation of hexavalent chromium and methylene blue

    International Nuclear Information System (INIS)

    Pandikumar, Alagarsamy; Ramaraj, Ramasamy

    2012-01-01

    Graphical abstract: Aminosilicate sol–gel supported TiO 2 –Au nanocomposite material photocatalyst was prepared by deposition–precipitation method and used for the simultaneous oxidation and reduction of methyelene blue dye and Cr(VI) ions. Highlights: ► The EDAS/(TiO 2 –Au) nps is used to design the solid-phase thin film photocatalyst. ► Au promotes the interfacial electron transfer from TiO 2 to Cr(VI) to form Cr(III). ► The holes produced at the TiO 2 oxidize the MB dye. ► The EDAS/(TiO 2 –Au) nps film was used for the simultaneous oxidation and reduction of toxic molecules. ► The photoinduced simultaneous redox process provides dual benefit for the environment remediation. - Abstract: Aminosilicate sol–gel supported titanium dioxide–gold (EDAS/(TiO 2 –Au) nps ) nanocomposite materials were synthesized by simple deposition–precipitation method and characterized. The photocatalytic oxidation and reduction activity of the EDAS/(TiO 2 –Au) nps film was evaluated using hexavalent chromium (Cr(VI)) and methylene blue (MB) dye under irradiation. The photocatalytic reduction of Cr(VI) to Cr(III) was studied in the presence of hole scavengers such as oxalic acid (OA) and methylene blue (MB). The photocatalytic degradation of MB was investigated in the presence and absence of Cr(VI). Presence of Au nps on the (TiO 2 ) nps surface and its dispersion in the silicate sol-gel film (EDAS/(TiO 2 –Au) nps ) improved the photocatalytic reduction of Cr(VI) and oxidation of MB due to the effective interfacial electron transfer from the conduction band of the TiO 2 to Au nps by minimizing the charge recombination process when compared to the TiO 2 and (TiO 2 –Au) nps in the absence of EDAS. The EDAS/(TiO 2 –Au) nps nanocomposite materials provided beneficial role in the environmental remediation and purification process through synergistic photocatalytic activity by an advanced oxidation–reduction processes.

  15. Influence of the Sol-Gel pH Process and Compact Film on the Efficiency of TiO-Based Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    A. O. T. Patrocinio

    2012-01-01

    Full Text Available The influence of pH during hydrolysis of titanium(IV isopropoxide on the morphological and electronic properties of TiO2 nanoparticles prepared by the sol-gel method is investigated and correlated to the photoelectrochemical parameters of dye-sensitized solar cells (DSCs based on TiO2 films. Nanoparticles prepared under acid pH exhibit smaller particle size and higher surface area, which result in higher dye loadings and better short-circuit current densities than DSCs based on alkaline TiO2-processed films. On the other hand, the product of charge collection and separation quantum yields in films with TiO2 obtained by alkaline hydrolysis is c.a. 27% higher than for the acid TiO2 films. The combination of acid and alkaline TiO2 nanoparticles as mesoporous layer in DSCs results in a synergic effect with overall efficiencies up to 6.3%, which is better than the results found for devices employing one of the nanoparticles separately. These distinct nanoparticles can be also combined by using the layer-by-layer technique (LbL to prepare compact TiO2 films applied before the mesoporous layer. DSCs employing photoanodes with 30 TiO2 bilayers have shown efficiencies up to 12% higher than the nontreated photoanode ones. These results can be conveniently used to develop optimized synthetic procedures of TiO2 nanoparticles for several dye-sensitized solar cell applications.

  16. Effect of heating temperature on the optical properties of sol-gel synthesized C/NiO nanocomposite thin films

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2011-05-01

    Full Text Available photo-thermal conversion have shown the feasibility of the C/NiO composite coatings for a selective solar absorber application, nonetheless, a detailed systematic investigation on the effect of the sol-gel fabrication process parameters on the structural...

  17. The Preparation of TiO₂ Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property.

    Science.gov (United States)

    Liang, Yu; Sun, Sijia; Deng, Tongrong; Ding, Hao; Chen, Wanting; Chen, Ying

    2018-03-19

    TiO₂ sol was produced by the sol-gel method through the hydrolysis and the aging of tetrabutyl titanate and the TiO₂ film was obtained by dipping and uniform lifting of the acid-treated and ultrasound-treated clean glass slides into the TiO₂ sol followed by aging, drying, and calcination. The effect of the hydrolysis control agents to the formed sol was researched and the crystalline state, the morphology, and the photocatalytic properties of the products after calcination were characterized. The structural morphology, the contact angles before and after illumination, and the self-cleaning properties of the TiO₂ film were characterized as well. The results showed that by using acetylacetone as the hydrolysis control agent, the formed TiO₂ sol had relatively high stability. The product after the calcination of the TiO₂ sol was of single anatase type with crystalline size of 18-20 nm and it could degrade nearly 100% of methylene blue after 90 min illumination. The formed TiO₂ film is compact, continuous, smooth, and had the properties of super-hydrophilicity (after 30 min illumination due to its contact angle decreasing from 21° to nearly 0°) and anti-fogging capability, which indicated its excellent self-cleaning property.

  18. Structural, vibrational, and gasochromic properties of porous WO sub 3 films templated with a sol-gel organic-inorganic hybrid

    CERN Document Server

    Opara-Krasovec, U; Orel, B; Grdadolnik, J; Drazic, G

    2002-01-01

    The structure and the gasochromic properties of sol-gel-derived WO sub 3 films with a monoclinic structure (m-WO sub 3) were studied by focusing attention on the size of the monoclinic grains. The size of the m-WO sub 3 grains is modified by the addition of an organic-inorganic hybrid to the initial peroxopolytungstic acid (W-PTA) sols which are based on chemically bonded poly-(propylene glycol) to triethoxysilane end-capping groups (ICS-PPG). The results obtained with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the heat treatment (500 sup o C) of WO sub 3 /ICS- IPG (0.5, 1, 2, 5, and 10 mol%) composite films results in a change of their morphology, and nanodimensional pores are formed between the grains. High-resolution TEM (HRTEM) analysis revealed the presence of an amorphous phase on the outside of the m-WO sub 3 grains, whereas energy-dispersive x-ray spectra (EDXS) showed that this amorphous phase contained W and Si. Impregnation of the WO sub 3 /ICS-PPG film ...

  19. Determinação da espessura de filme bioativo SiO2-CaO-P2O5 obtido via sol-gel Evaluation of the thickness of SiO2-CaO-P2O5 bioactive film obtained via sol-gel

    Directory of Open Access Journals (Sweden)

    S. R. Federman

    2009-06-01

    Full Text Available Foi preparado um filme bioativo do sistema SiO2-CaO-P2O5 via sol-gel pela hidrólise e condensação de TEOS, TEP, álcool e nitrato de cálcio em meio ácido. Após a mistura, a solução sintetizada serviu para revestir substrato de aço inoxidável pelo método de imersão utilizando baixa velocidade de emersão. Após o revestimento, o compósito foi tratado termicamente em diferentes temperaturas durante 1 h, com o propósito de avaliar a influência do tratamento térmico especificamente na espessura do filme revestindo o substrato metálico. A influência da variação da temperatura foi acessada através das técnicas de microscopia eletrônica de varredura (MEV e espectroscopia de centelhamento (GDS. Os resultados comprovaram a influência da temperatura na espessura do filme obtido. A reduzida espessura do filme bioativo foi determinada por MEV e GDS.A sol-gel bioactive film of the SiO2-CaO-P2O5 system was prepared, via a sol-gel method, by hydrolysis and condensation of tetraethylortosilicate [TEOS], triethylphosphate [TEP] and hydrated calcium nitrate under acidic conditions. After mixing, the as-obtained solution was used to coat stainless steel substrates by dip-coating in a low withdraw speed. After deposition, the composite was heat treated at different temperatures for 1 h to evaluate the temperature influence on the thickness of the coating over the stainless steel substrate. The development of the coating thickness was accessed through the techniques of scanning electronic microscopy (SEM and glow discharge spectroscopy (GDS. Results indicated the heat treatment effect on the film thickness. Also, the SEM and the GDS techniques were used to determine the thin bioactive coating thickness.

  20. A pentacene thin film transistor with good performance using sol-gel derived SiO2 gate dielectric layer

    Science.gov (United States)

    Cavas, M.; Al-Ghamdi, Ahmed A.; Al-Hartomy, O. A.; El-Tantawy, F.; Yakuphanoglu, F.

    2013-02-01

    A low-voltage pentacene field-effect transistor with sol-gel derived SiO2 gate dielectric was fabricated. The mobility of the transistor was achieved as high as 1.526 cm2/V on the bared SiO2/Si substrate by a higher dielectric constant. The interface state density for the transistor was found to vary from 3.8 × 1010 to 7.5 × 1010 eV-1 cm-2 at frequency range of 100 kHz-1 MHz. It is evaluated that the SiO2 derived by low cost sol-gel is quite a promising candidate as a gate dielectric layer for low-voltage pentacene field-effect transistor.

  1. Thin TiO2 Films Prepared by Inkjet Printing of the Reverse Micelles Sol-Gel Composition

    Czech Academy of Sciences Publication Activity Database

    Morozová, Magdalena; Klusoň, Petr; Krýsa, Josef; Dzik, P.; Veselý, M.; Šolcová, Olga

    2011-01-01

    Roč. 160, č. 1 (2011), s. 371-378 ISSN 0925-4005 R&D Projects: GA ČR GD203/08/H032; GA ČR GA104/09/0694; GA AV ČR KAN400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : sol-gel * titanium oxide * inkjet printing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.898, year: 2011

  2. Meso-porous α-Fe2O3 thin films synthesized via the sol-gel process for light-driven water oxidation

    International Nuclear Information System (INIS)

    Hamd, Wael; Laberty-Robert, Christel; Sanchez, Clement; Cobo, Saioa; Fize, Jennifer; Artero, Vincent; Baldinozzi, Gianguido; Schwartz, Wilfrid; Reymermier, Maryse; Pereira, Alexandre; Fontecave, Marc

    2012-01-01

    This work reports a facile and cost-effective method for synthesizing photoactive α-Fe 2 O 3 films as well as their performances when used as photoanodes for water oxidation. Transparent α-Fe 2 O 3 meso-porous films were fabricated by template-directed sol-gel chemistry coupled with the dip-coating approach, followed by annealing at various temperatures from 350 degrees C to 750 degrees C in air. α-Fe 2 O 3 films were characterized by X-ray diffraction, XPS, FE-SEM and electrochemical measurements. The photoelectrochemical performance of α-Fe 2 O 3 photoanodes was characterized and optimized through the deposition of Co-based co-catalysts via different methods (impregnation, electro-deposition and photo-electro-deposition). Interestingly, the resulting hematite films heat-treated at relatively low temperature (500 degrees C), and therefore devoid of any extrinsic dopant, achieve light-driven water oxidation under near-to-neutral (pH = 8) aqueous conditions after decoration with a Co catalyst. The onset potential is 0.75 V vs. the reversible hydrogen electrode (RHE), thus corresponding to 450 mV light-induced under potential, although modest photocurrent density values (40 μAcm -2 ) are obtained below 1.23 V vs. RHE. These new materials with a very large interfacial area in contact with the electrolyte and allowing for a high loading of water oxidation catalysts open new avenues for the optimization of photo-electrochemical water splitting. (authors)

  3. Electroluminescence properties of In-doped Zn2SiO4 thin films prepared by sol-gel process

    International Nuclear Information System (INIS)

    Ogawa, Hirotaka; Kan, Akinori; Ikeda, Norihiro; Fujita, Akihiro

    2012-01-01

    The effect of In doping on the electroluminescence (EL) properties of Zn 2 SiO 4 :In thin films was investigated. In-doped Zn 2 SiO 4 thin films were deposited on BaTiO 3 substrates and their EL properties were characterized in this study. X-ray powder diffraction patterns of In-doped Zn 2 SiO 4 powders revealed a single phase of Zn 2 SiO 4 for In concentrations up to approximately 1.5 mol%, whereas a secondary phase of In 2 O 3 was observed for In concentrations in the range of 2-10 mol%. The maximum luminance of thin film electroluminescent (TFEL) devices varied significantly with the amount of In doping. The highest luminance with blue emission was obtained when 2 mol% In was doped. The blue emission of In-doped Zn 2 SiO 4 thin film may be related to the In substitution for Zn. The 2 mol% In-doped Zn 2 SiO 4 thin film exhibited blue emission with CIE color coordinates of x=0.208 and y=0.086.

  4. Sodium and potassium doped P-type ZnO films by sol-gel spin-coating technique

    Science.gov (United States)

    Au, Benedict Wen-Cheun; Chan, Kah-Yoong

    2017-07-01

    Zinc oxide (ZnO) is a promising material in a variety of applications including sensors, transistors and solar cells. Many researchers studied N-type ZnO films and reported enhanced properties. On the other hand, P-type ZnO films were rarely attempted due to the self-compensation effect. Success in achieving P-type ZnO films is important as it will pave the way for more advanced complementary devices. In this work, P-type sodium and potassium doped ZnO films were fabricated on glass substrates with doping concentration between 0 and 25 at.%. The influences of doping concentration on surface morphology, structural, optical and electrical properties were investigated using atomic force microscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, ultraviolet-visible (UV-Vis) spectrophotometer, photoluminescence spectroscopy and Hall-effect electrical transport measurement system. The distinctive behavior of P-type ZnO films with different doping concentrations will be discussed.

  5. Sol gel-derived hydroxyapatite films over porous calcium polyphosphate substrates for improved tissue engineering of osteochondral-like constructs.

    Science.gov (United States)

    Lee, Whitaik David; Gawri, Rahul; Pilliar, Robert M; Stanford, William L; Kandel, Rita A

    2017-10-15

    Integration of in vitro-formed cartilage on a suitable substrate to form tissue-engineered implants for osteochondral defect repair is a considerable challenge. In healthy cartilage, a zone of calcified cartilage (ZCC) acts as an intermediary for mechanical force transfer from soft to hard tissue, as well as an effective interlocking structure to better resist interfacial shear forces. We have developed biphasic constructs that consist of scaffold-free cartilage tissue grown in vitro on, and interdigitated with, porous calcium polyphosphate (CPP) substrates. However, as CPP degrades, it releases inorganic polyphosphates (polyP) that can inhibit local mineralization, thereby preventing the formation of a ZCC at the interface. Thus, we hypothesize that coating CPP substrate with a layer of hydroxyapatite (HA) might prevent or limit this polyP release. To investigate this we tested both inorganic or organic sol-gel processing methods, asa barrier coating on CPP substrate to inhibit polyP release. Both types of coating supported the formation of ZCC in direct contact with the substrate, however the ZCC appeared more continuous in the tissue formed on the organic HA sol gel coated CPP. Tissues formed on coated substrates accumulated comparable quantities of extracellular matrix and mineral, but tissues formed on organic sol-gel (OSG)-coated substrates accumulated less polyP than tissues formed on inorganic sol-gel (ISG)-coated substrates. Constructs formed with OSG-coated CPP substrates had greater interfacial shear strength than those formed with ISG-coated and non-coated substrates. These results suggest that the OSG coating method can modify the location and distribution of ZCC and can be used to improve the mechanical integrity of tissue-engineered constructs formed on porous CPP substrates. Articular cartilage interfaces with bone through a zone of calcified cartilage. This study describes a method to generate an "osteochondral-like" implant that mimics this

  6. Comparison of the method of diffusive gels in thin films with conventional extraction techniques for evaluating zinc accumulation in plants and isopods

    International Nuclear Information System (INIS)

    Koster, Marijke; Reijnders, Lucas; Oost, Nathalie R. van; Peijnenburg, Willie J.G.M.

    2005-01-01

    The measurement of diffusive gels in thin films (DGT) has recently been developed to assess metal bioavailability in soils. The DGT-method is based on diffusion in a porous matrix. To test the predictive capabilities of the method with regard to metal bioavailability, a study was set up with 28 soils having a variety of textures and amounts of zinc salts added. Correlation and regression analyses were performed to compare DGT-extracted zinc levels to zinc concentrations obtained by extraction with 0.01 M CaCl 2 and 0.43 M HNO 3 , digestion with aqua regia and the zinc concentration in pore water. The amount of zinc extracted with CaCl 2 correlated well with DGT-extracted zinc levels in all soils spiked with different amounts of ZnCl 2 . A similar correlation was not found for zinc concentrations in soil samples collected in the field. Experiments were performed to compare zinc content in organisms and in soils. The organisms tested were plants (grass, lettuce and lupine) and the hard bodied soil dwelling isopod Oniscus asellus. Good correlations were found between zinc accumulation in grass and lettuce and the C E (effective concentration) measured by a DGT-device, CaCl 2 extracted zinc and the zinc content in the pore water of all soils. The correlation with C E was not significant for lupine, neither for spiked soils, nor for field soils (p ≤ 0.001). Zinc levels in the isopods were not significantly related to any set of zinc measurements. From a synthesis of all results obtained it is concluded that the DGT-methodology does not have an additional value in predicting bioavailability of zinc in terrestrial ecosystems as compared to conventional extraction methods. - Capsule: The newly developed method of diffusive gels in Thin films (DGT) does not have an added value over conventional extraction techniques in predicting zinc uptake by plants and isopods

  7. Influence of Ce(III/Ce(IV - supplements on the Characteristics of Humidity Sensors with TiO2 Films Prepared via a Sol-gel Method

    Directory of Open Access Journals (Sweden)

    Kozhukharov, S.

    2013-04-01

    Full Text Available Humidity sensors have been prepared via a sol-gel method to deposit TiO2 films with additions of Ce-compounds on alumina substrates, with interdigitated silver palladium electrodes. Observations by scanning electron microscopy (SEM were performed in order to determine the surface morphology of the respective layers. Structural and compositional characterization was done by X-ray diffraction analysis (XRD, and energy dispersive X-ray spectroscopy (EDX for investigation of the relation between the film structures and the parameters of the respective sensors. The influence of Ce-compounds on the electrical characteristics of the samples as humidity sensing elements has been evaluated by an impedance analyzer.Los sensores de humedad han sido desarrollados mediante el método sol-gel para depositar películas superficiales basadas en TiO2 con adiciones de compuestos de cerio sobre sustratos de corindón y electrodos de aleación de plata y paladio. Se han realizado observaciones mediante el Microscopio Electrónico de Barrido (MEB para determinar la morfología superficial de las capas respectivas. Las caracterizaciones de la estructura y composición han sido realizadas mediante Difracción de Rayos X (DRX y espectroscopía de dispersión energética de rayos X (EDERX, con el fin de investigar la relación entre la estructura de las capas y los parámetros de los sensores respectivos. La influencia de los compuestos de cerio sobre las características eléctricas de los sensores de humedad obtenidos se ha evaluado mediante el análisis de impedancia eléctrica.

  8. Influence of initial pH on the microstructure of YBa2Cu3O7−x superconducting thin films derived from DEA-aqueous sol–gel method

    DEFF Research Database (Denmark)

    Xiao, Tang; Yue, Zhao; Grivel, Jean-Claude

    2013-01-01

    A fluorine-free aqueous sol–gel technique was used to fabricate YBCO superconducting thin films. Acetic acid was added in order to modify the complexation process taking place between the metal cations and the organic chelating agents. The electrical resistance and the pH value were used as indic...

  9. Visible emission from Er-doped SnO2 thin films deposited by sol-gel Emissão no visível de filmes finos, depositados via sol-gel, de SnO2 dopados com Er

    Directory of Open Access Journals (Sweden)

    L. P. Ravaro

    2007-06-01

    Full Text Available Emission from Er-doped SnO2 thin film deposited via sol-gel by the dip coating technique is obtained in the range 500-700 nm with peak at 530 nm (green. Electron-hole generation in the tin dioxide matrix is used to promote the rare-earth ion excitation. Evaluation of crystallite dimensions through X-ray diffraction results leads to nanoscopic size, what could play a relevant role in the emission spectra. The electron-hole mechanism is also responsible for the excitation of the transition in the 1540 nm range in powders obtained from the same precursor solution of films. The thin film matrix presents a very useful shape for technological application, since it allows integration in optical devices and the application of electric fields to operate electroluminescent devices.Foi obtida emissão de filmes finos de SnO2 dopados com Er no intervalo 500-700 nm, com pico em 530 nm (verde. Esses filmes foram depositados pela técnica de molhamento via sol-gel. A geração de pares elétron-buraco na matriz de SnO2 é usada para promover a excitação do íon terra-rara. A avaliação do tamanho dos cristalitos por meio de resultados de difração de raios X indica dimensões nanoscópicas, o que pode ser relevante para a interpretação do espectro de emissão. O mecanismo de excitação elétron-buraco é também responsável pela excitação da transição no intervalo que inclui 1540 nm em pós obtidos da mesma solução precursora dos filmes. Filmes finos constituem um formato muito útil para aplicações tecnológicas, desde que permite integração em dispositivos ópticos e a aplicação de campos elétricos para operar dispositivos eletroluminescentes.

  10. Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Suzannah R. [Department; Woods, Keenan N. [Department; Plassmeyer, Paul N. [Department; Marsh, David A. [Department; Johnson, Darren W. [Department; Page, Catherine J. [Department; Jensen, Kirsten M. Ø. [Department; Johnson, David C. [Department

    2017-04-03

    Amorphous metal oxides are central to a variety of technological applications. In particular, indium gallium oxide has garnered attention as a thin-film transistor channel layer material. In this work we examine the structural evolution of indium gallium oxide gel-derived powders and thin films using infrared vibrational spectroscopy, X-ray diffraction, and pair distribution function (PDF) analysis of X-ray total scattering from standard and normal incidence thin-film geometries (tfPDF). We find that the gel-derived powders and films from the same aqueous precursor evolve differently with temperature, forming mixtures of Ga-substituted In2O3 and In-substituted β-Ga2O3 with different degrees of substitution. X-ray total scattering and PDF analysis indicate that the majority phase for both the powders and films is an amorphous/nanocrystalline β-Ga2O3 phase, with a minor constituent of In2O3 with significantly larger coherence lengths. This amorphous β-Ga2O3 phase could not be identified using the conventional Bragg diffraction techniques traditionally used to study crystalline metal oxide thin films. The combination of Bragg diffraction and tfPDF provides a much more complete description of film composition and structure, which can be used to detail the effect of processing conditions and structure–property relationships. This study also demonstrates how structural features of amorphous materials, traditionally difficult to characterize by standard diffraction, can be elucidated using tfPDF.

  11. Schottky emission in nanoscopically crystallized Ce-doped SnO{sub 2} thin films deposited by sol-gel-dip-coating

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Marco A.L.; Pineiz, Tatiane F.; Morais, Evandro A. de [Department of Physics-FC, Sao Paulo State University, UNESP, C. Postal 473, 17033-360, Bauru SP (Brazil); P. Pos-Graduacao em Ciencia e Tecnologia de Materiais (POSMAT), UNESP (Brazil); Scalvi, Luis V.A. [Department of Physics-FC, Sao Paulo State University, UNESP, C. Postal 473, 17033-360, Bauru SP (Brazil)], E-mail: scalvi@fc.unesp.br; Saeki, Margarida J. [Department of Chemistry and Biochemistry-IB, Sao Paulo State University, UNESP, C.P. 510, 18618-000, Botucatu SP (Brazil); Cavalheiro, Alberto A. [Chemistry Unity of Navirai, Mato Grosso do Sul State University, UEMS, 79950-000, Navirai MS (Brazil)

    2008-11-28

    This paper reports the electrical effects of the incorporation of Ce(III) or Ce(IV) in SnO{sub 2} thin films, prepared by the sol-gel-dip-coating technique. This doping has drastically increased the resistivity compared to undoped thin films. Nanoscopic dimension of crystallites, in the range 5-10 nm, contributes to this increase. The high number of crystallites decreases the mobility due to the increase of the density of potential barrier between grains per unit of volume. High doping leads to low conductivity when Ce(III) salt is used as precursor, which assures the acceptor-like nature of this ion in the matrix. Current as function of voltage, measured for several temperatures, leads to the predominance of Schottky conduction mechanism, even though a tunneling process seems to be a good approximation for the observed deviations at lower applied electric fields. The potential barrier for Schottky emission is in the range 0.6-0.8 eV. For Ce(IV) doping, an increase of the grain boundary depletion layer seems to be responsible for the observed high resistivity, because it leads to higher electron scattering at grain boundary. Measurements done under room atmosphere lead to a higher barrier height than measurement done under vacuum conditions, due to oxygen adsorption at particles surface. For temperatures higher than 150 deg. C , under vacuum conditions, the elimination of O{sub 2}{sup -} species becomes probable, increasing considerably the current density.

  12. Electrical characteristics and density of states of thin-film transistors based on sol-gel derived ZnO channel layers with different annealing temperatures

    Science.gov (United States)

    Wang, S.; Mirkhani, V.; Yapabandara, K.; Cheng, R.; Hernandez, G.; Khanal, M. P.; Sultan, M. S.; Uprety, S.; Shen, L.; Zou, S.; Xu, P.; Ellis, C. D.; Sellers, J. A.; Hamilton, M. C.; Niu, G.; Sk, M. H.; Park, M.

    2018-04-01

    We report on the fabrication and electrical characterization of bottom gate thin-film transistors (TFTs) based on a sol-gel derived ZnO channel layer. The effect of annealing of ZnO active channel layers on the electrical characteristics of the ZnO TFTs was systematically investigated. Photoluminescence (PL) spectra indicate that the crystal quality of the ZnO improves with increasing annealing temperature. Both the device turn-on voltage (Von) and threshold voltage (VT) shift to a positive voltage with increasing annealing temperature. As the annealing temperature is increased, both the subthreshold slope and the interfacial defect density (Dit) decrease. The field effect mobility (μFET) increases with annealing temperature, peaking at 800 °C and decreases upon further temperature increase. An improvement in transfer and output characteristics was observed with increasing annealing temperature. However, when the annealing temperature reaches 900 °C, the TFTs demonstrate a large degradation in both transfer and output characteristics, which is possibly produced by non-continuous coverage of the film. By using the temperature-dependent field effect measurements, the localized sub-gap density of states (DOSs) for ZnO TFTs with different annealing temperatures were determined. The DOSs for the subthreshold regime decrease with increasing annealing temperature from 600 °C to 800 °C and no substantial change was observed with further temperature increase to 900 °C.

  13. Direct imprinting of indium–tin-oxide precursor gel and simultaneous formation of channel and source/drain in thin-film transistor

    Science.gov (United States)

    Haga, Ken-ichi; Kamiya, Yuusuke; Tokumitsu, Eisuke

    2018-02-01

    We report on a new fabrication process for thin-film transistors (TFTs) with a new structure and a new operation principle. In this process, both the channel and electrode (source/drain) are formed simultaneously, using the same oxide material, using a single nano-rheology printing (n-RP) process, without any conventional lithography process. N-RP is a direct thermal imprint technique and deforms oxide precursor gel. To reduce the source/drain resistance, the material common to the channel and electrode is conductive indium–tin-oxide (ITO). The gate insulator is made of a ferroelectric material, whose high charge density can deplete the channel of the thin ITO film, which realizes the proposed operation principle. First, we have examined the n-RP conditions required for the channel and source/drain patterning, and found that the patterning properties are strongly affected by the cooling rate before separating the mold. Second, we have fabricated the TFTs as proposed and confirmed their TFT operation.

  14. Facile fabrication of Ag-Pd bimetallic nanoparticles in ultrathin TiO(2)-gel films: nanoparticle morphology and catalytic activity.

    Science.gov (United States)

    He, Junhui; Ichinose, Izumi; Kunitake, Toyoki; Nakao, Aiko; Shiraishi, Yukihide; Toshima, Naoki

    2003-09-10

    Ag-Pd bimetallic nanoparticles were prepared directly in ultrathin TiO(2)-gel films by a stepwise ion-exchange/reduction approach. Ion-exchange sites were created in ultrathin films using Mg(2+) ions as template. Ag(+) ion was then incorporated by ion exchange, and converted into metallic nanoparticles by low-temperature H(2) plasma, regenerating ion-exchange sites. The same procedure was then carried out for Pd(2+) ion, producing Pd-on-Ag bimetallic nanoparticles, as TEM observation and plasmon resonance absorption indicate. By contrast, reversed metal incorporation procedure appeared to give a mixture of individual Ag and Pd nanoparticles, as confirmed by TEM, absorption spectroscopy and X-ray photoelectron spectroscopy. For hydrogenation of methyl acrylate, the catalytic activity of the Pd-on-Ag nanoparticle is 367 times as large as that of commercial Pd black and 1.6 times as large as that of Pd monometallic nanoparticle. The outstanding catalytic activity was explicable by the large fraction of the surface-exposed Pd atoms. The formation process of the bimetallic nanoparticle and their general morphological feature are discussed.

  15. Highly improved photo-induced bias stability of sandwiched triple layer structure in sol-gel processed fluorine-doped indium zinc oxide thin film transistor

    Directory of Open Access Journals (Sweden)

    Dongha Kim

    2016-03-01

    Full Text Available In order to improve the reliability of TFT, an Al2O3 insulating layer is inserted between active fluorine doped indium zinc oxide (IZO:F thin films to form a sandwiched triple layer. All the thin films were fabricated via low-cost sol-gel process. Due to its large energy bandgap and high bonding energy with oxygen atoms, the Al2O3 layer acts as a photo-induced positive charge blocking layer that effectively blocks the migration of both holes and V o2+ toward the interface between the gate insulator and the semiconductor. The inserted Al2O3 triple layer exhibits a noticeably low turn on voltage shift of −0.7 V under NBIS as well as the good TFT performance with a mobility of 10.9 cm2/V ⋅ s. We anticipate that this approach can be used to solve the stability issues such as NBIS, which is caused by inescapable oxygen vacancies.

  16. Ferroelectric lanthanum-substituted Bi4Ti3O12 thin films fabricated on p-type Si(100) substrates by a sol-gel method

    International Nuclear Information System (INIS)

    Bae, Ji Cheul; Kim, Sang Su; Kim, Won-Jeong; Choi, Eun Kyung; Song, Tae Kwon

    2004-01-01

    Bi 3.25 La 0.75 Ti 3 O 12 (BLT) thin films have been successfully fabricated on p-type Si(100) substrates by a sol-gel spin-coating method. The microstructures and surface morphologies of the BLT thin films on p-type Si(100) substrates annealed at 700 deg. C for 30 min in oxygen atmosphere were examined by an X-ray diffractometer and a scanning electron microscope, respectively. The BLT/p-type Si(100) capacitors annealed at 700 deg. C for 30 min exhibit good capacitance-voltage (C-V) characteristics and large memory window of approximately 6 V with a sweep voltage of ±16 V. From the frequency dependency of C-V characteristics of the BLT/p-type Si(100) capacitors, the fixed charge density (N fc ) at the interface of BLT/p-type Si(100) was calculated as approximately 1.24x10 12 /cm 2 . The humps and valleys observed in C-V curves were interpreted by introducing the electron charge injection and barrier-lowering effect at the interface of BLT/p-type Si(100). Based on the voltage and the frequency dependent C-V measurements, the memory windows of BLT/p-type Si(100) capacitor are significantly influenced by the electron charge injection and polarization reverse

  17. Growth and characterization of ceria thin films and Ce-doped γ-Al2O3 nanowires using sol-gel techniques.

    Science.gov (United States)

    Gravani, S; Polychronopoulou, K; Stolojan, V; Cui, Q; Gibson, P N; Hinder, S J; Gu, Z; Doumanidis, C C; Baker, M A; Rebholz, C

    2010-11-19

    γ-Al(2)O(3) is a well known catalyst support. The addition of Ce to γ-Al(2)O(3) is known to beneficially retard the phase transformation of γ-Al(2)O(3) to α-Al(2)O(3) and stabilize the γ-pore structure. In this work, Ce-doped γ-Al(2)O(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 °C for 6 h resulted in the crystallization of the Ce-doped AlOOH gel to form Ce-doped γ-Al(2)O(3) nanowires. Ce(3+) ions within the nanowires were present at a concentration of surface, a nanocrystalline CeO(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 γ-Al(2)O(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.

  18. Annealing effects on the phase and microstructure transformations of nanocrystalline (ZrO 2) 1- x(Sc 2O 3) x ( x=0.02-0.16) thin films deposited by sol-gel method

    Science.gov (United States)

    Zhang, Yawen; Jin, Shu; Yang, Yu; Liao, Chunsheng; Yan, Chunhua

    2002-06-01

    Annealing effects on the phase and microstructure transformations of the sol-gel derived nanocrystalline (ZrO 2) 1- x(Sc 2O 3) x ( x=0.02-0.16) films with the thickness of 0.6 μm on Si(100) substrate were investigated by X-ray diffraction and scanning electron microscopy. At annealing temperatures below 800 °C, the presence of a tetragonal or cubic phase for all the films was yielded due to the crystallite size effect. However, at higher temperatures, the determined phase compositions of the as-deposited films support that of the Sc-doped zirconia polycrystalline. After long annealing times, the films with x=0.02 and 0.08 displayed a phase decomposition, attributed to the metastability of the Sc-doped zirconia nanocrystals. On the other hand, both increasing annealing temperature and time could induce grain growth for a given film.

  19. Sol-gel synthesis of xTiO{sub 2}(100 − x)SiO{sub 2} nanocomposite thin films: Structure, optical and antireflection properties

    Energy Technology Data Exchange (ETDEWEB)

    Kermadi, S., E-mail: kermadisalim@yahoo.fr [CRTSE—Division DDCS, 02 Bd Dr. Frantz Fanon BP, 140, les 07 merveilles, 16038, Algiers (Algeria); Agoudjil, N. [Department of Chemistry, Laboratory of Physico-Chemistry of Materials and Environment, USTHB, BO Box 32 El Alia, 16111 Algiers (Algeria); Sali, S.; Boumaour, M. [CRTSE—Division DDCS, 02 Bd Dr. Frantz Fanon BP, 140, les 07 merveilles, 16038, Algiers (Algeria); Bourgeois, S.; Marco de Lucas, M.C. [Interdisciplinary Laboratory Carnot of Bourgogne, University of Bourgogne, 9 Av. A. Savary, PO Box 47 870, F-21078 Dijon (France)

    2014-08-01

    Sol-gel xTiO{sub 2}(100 − x)SiO{sub 2} nanocomposite thin films with x = 0, 25, 50, 75 and 100 mol % were dip-coated on glass and silicon substrates. The influence of the composition on structure, morphology and optical properties was studied by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electronic microscopy, monochromatic ellipsometry at λ = 632.8 nm and ultraviolet–visible absorbance spectroscopy. The optical properties were discussed on the basis of the microstructure. After annealing at 500 °C, results showed high pure materials, homogenous crack-free surfaces with good adherence and high optical qualities. The 100% TiO{sub 2} crystallizes in the anatase phase and exhibits nanograins of 6 to 10 nm in size. However, all the other compositions are amorphous with comparable grains around 4 nm in size. The averaged transmittance decreases with increasing the TiO{sub 2} content but remains higher than 90%. Whatever the composition, the coating thickness increases linearly as the withdrawal speed increases from 10 to 54 mm/minute. The relationship between refractive index and composition was analyzed by fitting the experimental data to different theoretical models for the refractive index of mixed films. Results showed that depending on the withdrawal speed, the data can properly fit either the Drude or the linear models. Thus, the film thickness can be adjusted by the control of the withdrawal speed. However, the control of the composition allows easily the tuning of the refractive index from 1.48 to 2.18 at λ = 632.8 nm to achieve optimum anti-reflection characteristics. Different anti-reflection designs of both single and double layers were experimentally examined. Gains (assigned to the reduction of reflection losses) up to 54 and 63% were predicted with 75% TiO{sub 2} single-coating and SiO{sub 2}/TiO{sub 2} double-coatings respectively. - Highlights: • Stable sol for dip-coating xTiO{sub 2}(100 − x

  20. Inkjet-printed thin film radio-frequency capacitors based on sol-gel derived alumina dielectric ink

    KAUST Repository

    McKerricher, Garret

    2017-05-03

    There has been significant interest in printing radio frequency passives, however the dissipation factor of printed dielectric materials has limited the quality factor achievable. Al2O3 is one of the best and widely implemented dielectrics for RF passive electronics. The ability to spatially pattern high quality Al2O3 thin films using, for example, inkjet printing would tremendously simplify the incumbent fabrication processes – significantly reducing cost and allowing for the development of large area electronics. To-date, particle based Al2O3 inks have been explored as dielectrics, although several drawbacks including nozzle clogging and grain boundary formation in the films hinder progress. In this work, a particle free Al2O3 ink is developed and demonstrated in RF capacitors. Fluid and jetting properties are explored, along with control of ink spreading and coffee ring suppression. The liquid ink is heated to 400 °C decomposing to smooth Al2O3 films ~120 nm thick, with roughness of <2 nm. Metal-insulator-metal capacitors, show high capacitance density >450 pF/mm2, and quality factors of ~200. The devices have high break down voltages, >25 V, with extremely low leakage currents, <2×10−9 A/cm2 at 1 MV/cm. The capacitors compare well with similar Al2O3 devices fabricated by atomic layer deposition.

  1. Comparison of the method of diffusive gels in thin films with conventional extraction techniques for evaluating zinc accumulation in plants and isopods

    Energy Technology Data Exchange (ETDEWEB)

    Koster, Marijke [National Institute of Public Health and the Environment, Laboratory for Ecological Risk Assessment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Open University Netherlands, Heerlen (Netherlands); Reijnders, Lucas [Open University Netherlands, Heerlen (Netherlands); Oost, Nathalie R. van [National Institute of Public Health and the Environment, Laboratory for Ecological Risk Assessment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Peijnenburg, Willie J.G.M. [National Institute of Public Health and the Environment, Laboratory for Ecological Risk Assessment, P.O. Box 1, 3720 BA Bilthoven (Netherlands)]. E-mail: wjgm.peijnenburg@rivm.nl

    2005-01-01

    The measurement of diffusive gels in thin films (DGT) has recently been developed to assess metal bioavailability in soils. The DGT-method is based on diffusion in a porous matrix. To test the predictive capabilities of the method with regard to metal bioavailability, a study was set up with 28 soils having a variety of textures and amounts of zinc salts added. Correlation and regression analyses were performed to compare DGT-extracted zinc levels to zinc concentrations obtained by extraction with 0.01 M CaCl{sub 2} and 0.43 M HNO{sub 3}, digestion with aqua regia and the zinc concentration in pore water. The amount of zinc extracted with CaCl{sub 2} correlated well with DGT-extracted zinc levels in all soils spiked with different amounts of ZnCl{sub 2}. A similar correlation was not found for zinc concentrations in soil samples collected in the field. Experiments were performed to compare zinc content in organisms and in soils. The organisms tested were plants (grass, lettuce and lupine) and the hard bodied soil dwelling isopod Oniscus asellus. Good correlations were found between zinc accumulation in grass and lettuce and the C{sub E} (effective concentration) measured by a DGT-device, CaCl{sub 2} extracted zinc and the zinc content in the pore water of all soils. The correlation with C{sub E} was not significant for lupine, neither for spiked soils, nor for field soils (p {<=} 0.001). Zinc levels in the isopods were not significantly related to any set of zinc measurements. From a synthesis of all results obtained it is concluded that the DGT-methodology does not have an additional value in predicting bioavailability of zinc in terrestrial ecosystems as compared to conventional extraction methods. - Capsule: The newly developed method of diffusive gels in Thin films (DGT) does not have an added value over conventional extraction techniques in predicting zinc uptake by plants and isopods.

  2. Sol-gel based TiO2 thin film deposition on frustules towards facile and scalable manufacturing

    Science.gov (United States)

    Li, A.; Wang, J.; Zhang, W.; McNaughton, R.; Anderson, S.; Zhang, X.

    2016-11-01

    Diatom frustules have drawn a lot of attention from engineering researchers in the past decades. As a type of biomaterial, diatom frustules have been applied in a variety of areas such as biosensors and solar cells due to their excellent material and optical properties. Titanium dioxide (TiO2), on the other hand, is also semiconductor material and photocatalyst, micro and nanoparticles of which can be found in applications such as dye sensitised solar cells (DSSC). It has been demonstrated that by using diatom frustule-TiO2 composite particles in DSSCs, the performance of the solar cells could be increased. In this paper, we introduce a sol- gel based method to deposit TiO2 layers on the surface of diatom frustules. TiO2 nanoparticles were deposited on the surface of the frustules. After a subsequent annealing process, TiO2 crystal grains were formed. The method in this paper has the potential for scalable manufacturing of frustule-TiO2 composite materials for future solar cell applications.

  3. Respective efficiencies of nuclear collisions and electronic excitations for precipitating Ag clusters in sol-gel films

    CERN Document Server

    Pivin, J C

    2002-01-01

    The growth of silver clusters in co-sputtered SiO sub 2 :Ag films under irradiation with increasing fluences of 1.5 MeV He or 3 MeV Au ions is investigated by recording spectra of optical extinction. The analysis of surface plasmon resonances in these very small clusters on basis of Mie theory permits to estimate more precisely their mean size than TEM images. A linear increase of the mean cluster size with the energy deposited by ions in electronic excitations and little effect of collision cascades are observed. The growth kinetics is ascribed to a process of desorption/re-adsorption of Ag atoms at the surface of clusters.

  4. Influence of titanium content and temperature on optical and mechanical properties of sol-gel derived TiO2/γ-glycidoxypropyltrimethoxysilane and methyltrimethoxysilane hybrid organic-inorganic films

    International Nuclear Information System (INIS)

    Que, Wenxiu; Hu, X

    2003-01-01

    The influence of titanium content and heat treatment temperature on the optical and mechanical properties of TiO 2 /γ-glycidoxypropyltrimethoxysilane and methyltrimethoxysilane hybrid films processed by the sol-gel technique are studied for photonic applications. Waveguide film with a thickness more than 1.60 μm is prepared by a single spin-coating process and low temperature heat treatment. Thermal gravimetric analysis, UV-visible spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy are used to investigate the optical and structural properties of the hybrid organic-inorganic films. The results indicate that a dense, low absorption, and high transparency in the visible and near infrared range waveguide films can be obtained at a low temperature. The hardness and Young's modulus of the films are characterized by a nanoindenter and they show a dependence on the heat-treatment temperature. Hardness as high as 6.60 Gpa is obtained in 0.5 M titanium content film and heat-treated at 800 deg. C. It is proposed that the high hardness of the film may be related to the carbon and titanium content in the film

  5. Effect of SiNx diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol–gel dip coating and reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Mohamed Nawfal Ghazzal

    2015-10-01

    Full Text Available We investigate the effect of the thickness of the silicon nitride (SiNx diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol–gel and physical methods (reactive sputtering are affected differentially by the intercalating SiNx diffusion barrier. Increasing the thickness of the SiNx diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol–gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiNx barrier diffusion. The SiNx barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed.

  6. Effects of additions of dimethyl siloxanes and ethylene oxide (SEO) copolymers in tensile break (Tb), in gels and swelling percentage of poly(n-vinyl-2-pyrrolidone) (PVP) crosslinking films by electron beams

    International Nuclear Information System (INIS)

    Souza, A.; Miranda, A.; Hutzler, B.; Silva, L.G.A.; Nunes, S.P.

    1997-01-01

    When PVP gels are irradiated a self-supported film formation occur because of a crosslinking process. Such process consists of the recombination of the macro radicals during the direct or indirect interaction of ionizing radiation producing tridimensional networks. The aim of this work is to improve the tensile break (Tb) of the film without any harm to its biomedic characteristics. Thus, the SEO copolymers were chosen like coadjuvants, which show excellent hydrophilic characteristic and have been used for medical purposes. It is observed that films constituted by 6% PVP in the presence of the agar show a maximum Tb equal to 0,05 Mpa. The adding of 2,5% of the SEO in such films increase the maximum Tb to 0,08 MPa, the elevation was of 60%.It is noticed also that the increase of SEO concentration promotes an increase in the gels percentage and a decrease of the swelling percentage. So we conclude that the presence of the SEO favors the increase of crosslinking degree where 2,5% of the copolymers in films constituted by 6% of PVP and 0,4% of agar are enough to increase the Tb by 60%. (author). 13 refs., 4 figs

  7. Determination of the size and phase composition of silver nanoparticles in a gel film of bacterial cellulose by small-angle X-ray scattering, electron diffraction, and electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, V. V.; Klechkovskaya, V. V., E-mail: klechvv@ns.crys.ras.ru; Shtykova, E. V.; Dembo, K. A.; Arkharova, N. A.; Ivakin, G. I. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Smyslov, R. Yu. [Russian Academy of Sciences, Institute of Macromolecular Compounds (Russian Federation)

    2009-03-15

    The nanoscale structural features in a composite (gel film of Acetobacter Xylinum cellulose with adsorbed silver nanoparticles, stabilized by N-polyvinylpyrrolidone) have been investigated by small-angle X-ray scattering. The size distributions of inhomogeneities in the porous structure of the cellulose matrix and the size distributions of silver nanoparticles in the composite have been determined. It is shown that the sizes of synthesized nanoparticles correlate with the sizes of inhomogeneities in the gel film. Particles of larger size (with radii up to 100 nm) have also been found. Electron microscopy of thin cross sections of a dried composite layer showed that large particles are located on the cellulose layer surface. Electron diffraction revealed a crystal structure of silver nanoparticles in the composite.

  8. Co{sub 3}O{sub 4}/TiO{sub 2} films obtained by laser ablation and sol-gel for the reaction of oxygen liberation in alkaline medium; Peliculas de Co{sub 3}O{sub 4}/TiO{sub 2} obtenidas por ablacion laser y sol-gel para la reaccion de desprendimiento de oxigeno en medio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Perez A, J.; Fernandez V, S. M.; Escobar A, L.; Jimenez B, J. [Departamento de Quimica, ININ, Carretera Mexico-Toluca s/n, Ocoyoacac, Estado de Mexico (Mexico)

    2008-07-01

    The laser ablation technique known as Pulsed Laser Deposition (PLD) is used for obtaining thin films of TiO{sub 2}/SnO{sub 2}, which was later modified with Co{sub 3}O{sub 4} by PLD or by sol-gel technique. The films were characterized by X-ray diffraction, ultraviolet Vis and Raman spectroscopies, scanning electron microscopy and energy analysis of the dispersed X-rays produced by Auger decay. The anatase phase with particles of nano metric size was obtained by depositing the titanium dioxide in argon atmosphere. The Co{sub 3}O{sub 4} films obtained by PLD on the TiO{sub 2} showed the same morphology. The electrocatalytic activity of the films that were used as photo anodes for the reaction of oxygen liberation was carried out in the darkness, with environment light and the light emitted by a xenon lamp. The current density was higher for films of Co{sub 3}O{sub 4}/TiO{sub 2}/SnO{sub 2} obtained by PLD that for cobalt dioxide of mixed valence obtained by sol-gel. (Author)

  9. Surface engineering of artificial heart valve disks using nanostructured thin films deposited by chemical vapour deposition and sol-gel methods.

    Science.gov (United States)

    Jackson, M J; Robinson, G M; Ali, N; Kousar, Y; Mei, S; Gracio, J; Taylor, H; Ahmed, W

    2006-01-01

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti-coagulation drugs on a regular basis in order to minimize the formation of thrombosis. However, anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, i.e. strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and coefficient of friction values were obtained from pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also in this paper we report the preparation of freestanding nanocrystalline diamond films (FSND) using the time-modulated chemical vapour deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO2) coatings. The as-grown nc-TiO2 coatings were characterized for microstructure using SEM and XRD analysis.

  10. Caffeine electrochemical sensor using imprinted film as recognition element based on polypyrrole, sol-gel, and gold nanoparticles hybrid nanocomposite modified pencil graphite electrode.

    Science.gov (United States)

    Rezaei, Behzad; Khalili Boroujeni, Malihe; Ensafi, Ali A

    2014-10-15

    In the present study, a novel sensitive and selective nanocomposite imprinted electrochemical sensor for the indirect determination of caffeine has been prepared. The imprinted sensor was fabricated on the surface of pencil graphite electrode (PGE) via one-step electropolymerization of the imprinted polymer composed of conductive polymer, sol-gel, gold nanoparticles (AuNPs), and caffeine. Due to such combination like the thin film of molecularly imprinted polymer (MIP) with specific binding sites, the sensor responded quickly to caffeine. AuNPs were introduced for the enhancement of electrical response by facilitating charge transfer processes of [Fe(CN)6](3-)/[Fe(CN)6](4-) which was used as an electrochemical active probe. The fabrication process of the sensor was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Several important parameters controlling the performance of the sensor were investigated and optimized. The imprinted sensor has the advantages of high porous surface structure, inexpensive, disposable, excellent stability, good reproducibility and repeatability. The linear ranges of the MIP sensor were in the range from 2.0 to 50.0 and 50.0 to 1000.0 nmol L(-1), with the limit of detection (LOD) of 0.9 nmol L(-1) (S/N=3). Furthermore, the proposed method was successfully intended for the determination of caffeine in real samples (urine, plasma, tablet, green tea, energy and soda drink). Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Resistividade do filme depositado via sol-gel e estado de oxidação do dopante Ce na matriz SnO2 Resistivity of the film deposited via sol-gel and oxidation state of Ce doping in SnO2 matrix

    Directory of Open Access Journals (Sweden)

    L. V. A. Scalvi

    2011-06-01

    Full Text Available Incorporação de Ce3+ ou Ce4+ em filmes finos de SnO2 depositados via sol-gel-dip-coating aumenta drasticamente a resistividade elétrica. No primeiro caso, temos comportamento aceitador do dopante, levando a matriz à alta compensação de carga. Por outro lado, para Ce4+, verifica-se aumento na largura da região de depleção do contorno de grão, resultando em maior espalhamento de elétrons. Medidas de caracterização elétrica sob pressão ambiente levam à barreiras de potencial mais altas do que as medidas sob vácuo, devido a adsorção de oxigênio na superfície das partículas. A presença de Ce3+ aumenta a transmitância no infravermelho, o que significa menor quantidade de elétrons livres. Dados de XANES confirmam que o tratamento térmico a 550 ºC dos filmes, ainda que promova oxidação parcial para Ce4+, preserva uma quantidade significativa (em torno de 60% no estado Ce3+. Espectroscopia Raman mostra a evolução dos modos de vibração intra-grãos de SnO2 com o aumento da temperatura de tratamento térmico.Incorporation of Ce3+ or Ce4+ in sol-gel dip-coating SnO2 thin films increases drastically its electrical resistivity. In the first case, it is due the acceptor-like nature of the doping ion, leading the matrix to high charge compensation. On the other hand, for Ce+4 doped samples, it is verified a broadening of the grain boundary depletion layer. Measurements under room pressure leads to higher intergrain potential barriers when compared to measurements carried out under vacuum conditions, due to oxygen adsorption at particles surface. The presence of Ce3+ increases the infrared transmittance, which means a lower free electron concentration. XANES data confirms that the thermal annealing at 550 ºC of thin films, although promotes oxidation to Ce4+, still keeps a significantly amount (about 60% of ions in the oxidation state Ce3+. Raman spectroscopy data show the evolution of the SnO2 bulk vibration modes with

  12. New infrared-assisted method for sol-gel derived ZnO:Ag thin films: Structural and bacterial inhibition properties.

    Science.gov (United States)

    González-Penguelly, Brenely; Morales-Ramírez, Ángel de Jesús; Rodríguez-Rosales, Miriam Guadalupe; Rodríguez-Nava, Celestino Odín; Carrera-Jota, María Luz

    2017-09-01

    A new sol-gel method, based on crystallization with Infrared heating, was developed to obtain ZnO:Ag thin films. The common sol, with zinc acetate as precursor and silver nitrate as doping source (1, 3 and 5 % molar), isopropanol and distilled water as solvents and monoethanolamine as stabilizer agent; was modified with Pluronic F127 and diethylene glycol as rheological agents, and with urea as fuel to produce enough energy to the combustion and to promote the crystallization process. Later, Corning glass-substrates were dipped into the sol at a constant speed of 3mms -1 . To provide the necessary energy for obtaining the hexagonal ZnO structure of the coatings during the drying and consolidation process, instead of using the common furnace heat-treatment, the films were heated by means of an infrared (IR) ceramic lamp (800W) for 15, 30, 45, 60 and 180 minutes, and the effect of this annealing method was analyzed. The structural properties were examined by means of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), whereas morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The examination revealed a homogeneous distribution of particles with the characteristic pores of pluronic F127, and the coating roughness had an average value of 100nm by AFM. To evaluate the effect on the number of dipping cycles and the IR-treatment on the thickness, ellipsometry results for 1, 3 and 5 deposits were analyzed and showed increments of 780, 945 and 1082nm, respectively. Finally, to test of the antibacterial activity, instead of the common one-microorganism approach, environmental microorganisms that grow with expose of the broth to the ambient conditions were employed (microbial consortium), which is a real environmental condition. The biological test was carried out by kinetic growth inhibition (optical density) of heterotrophic bacteria in culture liquid media under conditions of light, light-dark and

  13. Impact of crystallisation processes on depth profile formation in sol-gel PbZr.sub.0·52./sub.Ti.sub.0·48./sub.O.sub.3./sub. thin films

    Czech Academy of Sciences Publication Activity Database

    Aulika, I.; Mergen, S.; Bencan, A.; Zhang, Q.; Dejneka, Alexandr; Kosec, M.; Kundzins, K.; Demarchi, D.; Civera, P.

    2013-01-01

    Roč. 112, č. 1 (2013), s. 53-58 ISSN 1743-6753 R&D Projects: GA TA ČR TA01010517; GA ČR GAP108/12/1941 Institutional research plan: CEZ:AV0Z10100522 Keywords : compositional and optical gradien * PZT * spectroscopic ellipsometry * crystallisation proces * sol-gel * XRD * thin film s * depth profile * spectroscopic elipsometry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2013

  14. Metal Oxide Thin Films Grafted on Silica Gel Surfaces: Recent Advances on the Analytical Application of these Materials

    Directory of Open Access Journals (Sweden)

    Gushikem Yoshitaka

    2001-01-01

    Full Text Available In the highly dispersed MxOy monolayer film on a porous SiO2 surface, denoted as SiO2/MxOy, the Si-O-M covalent bond formed on the SiO2 surface restricts the mobility of the attached oxide resulting in coordinatively unsaturated metal oxides (LAS in addition to the Brønsted acid sites (BAS. The BAS arise from the MOH and SiOH groups, the latter due to the unreacted silanol groups. As the attached oxides are strongly immobilized on the surface, they are also thermally very stable. The amphoteric character of most of the attached oxides allows the immobilization of various chemical species, acid or bases, resulting in a wide application of these surface modified materials. In this work many of the recent applications of these MxOy coated silica surfaces are described, such as selective adsorbents, in preconcentration processes, as new packing material for use in HPLC, support for immobilization of enzymes, amperometric electrodes, sensors and biosensors

  15. Influence of crystallisation on the photoluminescence properties of Y{sub 2-x}Er{sub x}Ti{sub 2}O{sub 7} sol-gel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jenouvrier, P. [Laboratoire des Materiaux et du Genie Physique, UMR 5628, INPG-CNRS, ENSPG, Domaine Universitaire, BP 46, 38402, Saint Martin d' Heres (France); Institut de Microelectronique, Electromagnetisme et Photonique, UMR 5130, INPG-UJF-CNRS, ENSERG, BP 257, 38016, Grenoble (France); Langlet, M. [Laboratoire des Materiaux et du Genie Physique, UMR 5628, INPG-CNRS, ENSPG, Domaine Universitaire, BP 46, 38402, Saint Martin d' Heres (France); Rimet, R.; Fick, J. [Institut de Microelectronique, Electromagnetisme et Photonique, UMR 5130, INPG-UJF-CNRS, ENSERG, BP 257, 38016, Grenoble (France)

    2003-10-01

    Optically active Er{sub 2}Ti{sub 2}O{sub 7} (ETO) and Y{sub 2-x}Er{sub x}Ti{sub 2}O{sub 7} (YETO) films have been successfully deposited using the aerosol-gel process. Several heat-treatment procedures are investigated in the 600-850 C range. ETO and YETO films start to crystallise in the pyrochlore phase at about 750 C, depending on the heat-treatment time. Crystalline YETO films form a solid solution where the erbium ions are well diluted. Up-conversion emission (UPE) in the visible wavelength range and infrared photoluminescence (PL) at 1.53 {mu}m are investigated. PL spectra are composed of several sharp peaks. Stark splitting of the {sup 4}I{sub 13/2} and {sup 4}I{sub 15/2} erbium levels is analysed. A clear correlation between spectroscopic properties and film microstructure is evidenced. YETO films exhibit strong PL compared to ETO films. PL lifetimes of up to 8.6 ms were measured on YETO films at an erbium concentration of 2 x 10{sup 20} ions/cm{sup 3}. The YETO compound is found to be a suitable material, improving the erbium active properties. (orig.)

  16. Structural and mechanical properties of lanthanide doped La1/3Nb0.8Ta0.2O3 thin films prepared by sol-gel method

    Science.gov (United States)

    Brunckova, Helena; Medvecky, Lubomir; Kovalcikova, Alexandra; Fides, Martin; Mudra, Erika; Durisin, Juraj; Skvarla, Jiri; Kanuchova, Maria

    2017-04-01

    Transparent Eu and Nd doped lanthanum niobate tantalate La1/3Nb0.8Ta0.2O3 (LNT) thin films (˜150 nm) were prepared by sol-gel/spin-coating process on Pt/SiO2/Si substrates and annealing at 1100 °C. The x-ray diffraction analysis of films confirmed formation of the perovskite La1/3NbO3 and La1/3TaO3 phases with traces of pyrochlore LaNbO4. Eu and Nd doped LNT films were smoother with roughness 17.1 and 25.4 nm in comparison with LNT (43.3 nm). In all films was observed heterogeneous microstructure with the perovskite spherical and pyrochlore needle-like particles. The mechanical properties of films were characterized for the first time by conventional and continuous stiffness (CSM) nanoindentation. The Eu and Nd doped LNT film modulus (E) and hardness (H) were higher than LNT (˜99.8 and 4.4 GPa) determined by conventional nanoindentation. It was measured the significant effect of substrate on properties of Eu or Nd films (H ˜ 5.9 or 4.9 GPa and E ˜ 107.3 or 104.1 GPa) by CSM nanoindentation.

  17. Control of gallium incorporation in sol–gel derived CuIn{sub (1−x)}Ga{sub x}S{sub 2} thin films for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bourlier, Yoan [Institut de Recherche sur les Composants logiciels et matériels pour l’Information et la Communication Avancée (IRCICA), CNRS USR 3380, Université Lille 1, 50 avenue Halley, 59655 Villeneuve d’Ascq CEDEX (France); Cristini Robbe, Odile [Institut de Recherche sur les Composants logiciels et matériels pour l’Information et la Communication Avancée (IRCICA), CNRS USR 3380, Université Lille 1, 50 avenue Halley, 59655 Villeneuve d’Ascq CEDEX (France); Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), CNRS UMR 8523, Université Lille, 59655 Villeneuve d’Ascq CEDEX (France); Lethien, Christophe [Institut de Recherche sur les Composants logiciels et matériels pour l’Information et la Communication Avancée (IRCICA), CNRS USR 3380, Université Lille 1, 50 avenue Halley, 59655 Villeneuve d’Ascq CEDEX (France); Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), CNRS UMR 8523, Université Lille, 59655 Villeneuve d’Ascq CEDEX (France); Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), CNRS UMR 8520, Avenue Poincaré, 59652 Villeneuve d’Ascq CEDEX (France); and others

    2015-10-15

    Highlights: • CuIn{sub (1−x)}Ga{sub x}S{sub 2} thin films were prepared by sol–gel process. • Evolution of lattice parameters is characteristic of a solid solution. • Optical band gap was found to be linearly dependent on the gallium rate. - Abstract: In this paper, we report the elaboration of Cu(In,Ga)S{sub 2} chalcopyrite thin films via a sol–gel process. To reach this aim, solutions containing copper, indium and gallium complexes were prepared. These solutions were thereafter spin-coated onto the soda lime glass substrates and calcined, leading to metallic oxides thin films. Expected chalcopyrite films were finally obtained by sulfurization of oxides layers using a sulfur atmosphere at 500 °C. The rate of gallium incorporation was studied both at the solutions synthesis step and at the thin films sulfurization process. Elemental and X-ray diffraction (XRD) analyses have shown the efficiency of monoethanolamine used as a complexing agent for the preparation of CuIn{sub (1−x)}Ga{sub x}S{sub 2} thin layers. Moreover, the replacement of diethanolamine by monoethanolamine has permitted the substitution of indium by isovalent gallium from x = 0 to x = 0.4 and prevented the precipitation of copper derivatives. XRD analyses of sulfurized thin films CuIn{sub (1−x)}Ga{sub x}S{sub 2,} clearly indicated that the increasing rate of gallium induced a shift of XRD peaks, revealing an evolution of the lattice parameter in the chalcopyrite structure. These results were confirmed by Raman analyses. Moreover, the optical band gap was also found to be linearly dependent upon the gallium rate incorporated within the thin films: it varies from 1.47 eV for x = 0 to 1.63 eV for x = 0.4.

  18. Sonicated sol–gel preparation of nanoparticulate ZnO thin films with various deposition speeds: The highly preferred c-axis (0 0 2) orientation enhances the final properties

    International Nuclear Information System (INIS)

    Malek, M.F.; Mamat, M.H.; Khusaimi, Z.; Sahdan, M.Z.; Musa, M.Z.; Zainun, A.R.; Suriani, A.B.; Md Sin, N.D.; Abd Hamid, S.B.; Rusop, M.

    2014-01-01

    Highlights: • Minimum stress of highly c-axis oriented ZnO was grown at suitable deposition speed. • The ZnO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZnO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on deposition speed. -- Abstract: Zinc oxide (ZnO) thin films have been deposited onto glass substrates at various deposition speeds by a sonicated sol–gel dip-coating technique. This work studies the effects of deposition speed on the crystallisation behaviour and optical and electrical properties of the resulting films. X-ray diffraction (XRD) analysis showed that thin films were preferentially oriented along the (0 0 2) c-axis direction of the crystal. The transformation sequence of strain and stress effects in ZnO thin films has also been studied. The films deposited at a low deposition speed exhibited a large compressive stress of 0.78 GPa, which decreased to 0.43 GPa as the deposition speed increased to 40 mm/min. Interestingly, the enhancement in the crystallinity of these films led to a significant reduction in compressive stress. All films exhibited an average transmittance of greater than 90% in the visible region, with absorption edges at ∼380 nm. The photoluminescence (PL) measurements indicated that the intensity of the emission peaks varied significantly with deposition speed. The optical band gap energy (E g ) was evaluated as 3.276–3.289 eV, which increased with decreasing compressive stress along the c-axis. The energy band gap of the resulting ZnO films was found to be strongly influenced by the preferred c-axis (0 0 2) orientation

  19. Sonicated sol–gel preparation of nanoparticulate ZnO thin films with various deposition speeds: The highly preferred c-axis (0 0 2) orientation enhances the final properties

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Mamat, M.H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Khusaimi, Z. [NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia); Sahdan, M.Z. [Microelectronic and Nanotechnology Centre (MiNT), Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Batu Pahat, Johor (Malaysia); Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Zainun, A.R. [Faculty of Electrical and Electronics Engineering, Universiti Malaysia Pahang (UMP), Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia); Suriani, A.B. [Department of Physics, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjung Malim, Perak (Malaysia); Md Sin, N.D. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Abd Hamid, S.B. [Nanotechnology and Catalysis Research Centre (NANOCAT), Universiti Malaya (UM), 50603 Kuala Lumpur (Malaysia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2014-01-05

    Highlights: • Minimum stress of highly c-axis oriented ZnO was grown at suitable deposition speed. • The ZnO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZnO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on deposition speed. -- Abstract: Zinc oxide (ZnO) thin films have been deposited onto glass substrates at various deposition speeds by a sonicated sol–gel dip-coating technique. This work studies the effects of deposition speed on the crystallisation behaviour and optical and electrical properties of the resulting films. X-ray diffraction (XRD) analysis showed that thin films were preferentially oriented along the (0 0 2) c-axis direction of the crystal. The transformation sequence of strain and stress effects in ZnO thin films has also been studied. The films deposited at a low deposition speed exhibited a large compressive stress of 0.78 GPa, which decreased to 0.43 GPa as the deposition speed increased to 40 mm/min. Interestingly, the enhancement in the crystallinity of these films led to a significant reduction in compressive stress. All films exhibited an average transmittance of greater than 90% in the visible region, with absorption edges at ∼380 nm. The photoluminescence (PL) measurements indicated that the intensity of the emission peaks varied significantly with deposition speed. The optical band gap energy (E{sub g}) was evaluated as 3.276–3.289 eV, which increased with decreasing compressive stress along the c-axis. The energy band gap of the resulting ZnO films was found to be strongly influenced by the preferred c-axis (0 0 2) orientation.

  20. Studying Structural, Optical, Electrical, and Sensing Properties of Nanocrystalline SnO2:Cu Films Prepared by Sol-Gel Method for CO Gas Sensor Application at Low Temperature

    Science.gov (United States)

    Al-Jawad, Selma M. H.; Elttayf, Abdulhussain K.; Saber, Amel S.

    Nanocrystalline SnO2 and SnO2:Cu thin films derived from SnCl2ṡ2H2O precursors have been prepared on glass substrates using sol-gel dip-coating technique. The deposited film was 300±20nm thick and the films were annealed in air at 500∘C for 1h. Structural, optical and sensing properties of the films were studied under different preparation conditions, such as Cu-doping concentration of 2%, 4% and 6wt.%. X-ray diffraction studies show the polycrystalline nature with tetragonal rutile structure of SnO2 and Cu:SnO2 thin films. The films have highly preferred orientation along (110). The crystallite size of the prepared samples reduced with increasing Cu-doping concentrations and the addition of Cu as dopants changed the structural properties of the thin films. Surface morphology was determined through scanning electron microscopy and atomic force microscopy. Results show that the particle size decreased as doping concentration increased. The films have moderate optical transmission (up to 82.4% at 800nm), and the transmittance, absorption coefficient and energy gap at different Cu-doping concentration were measured and calculated. Results show that Cu-doping decreased the transmittance and energy gap whereas it increased the absorption coefficient. Two peaks were noted with Cu-doping concentration of 0-6wt.%; the first peak was positioned exactly at 320nm ultraviolet emission and the second was positioned at 430-480nm. Moreover, emission bands were noticed in the photoluminescence spectra of Cu:SnO2. The electrical properties of SnO2 films include DC electrical conductivity, showing that the films have two activation energies, namely, Ea1 and Ea2, which increase as Cu-doping concentration increases. Cudoped nanocrystalline SnO2 gas-sensing material has better sensitivity to CO gas compared with pure SnO2.

  1. Effect of SiO{sub 2} addition on photocatalytic activity, water contact angle and mechanical stability of visible light activated TiO{sub 2} thin films applied on stainless steel by a sol gel method

    Energy Technology Data Exchange (ETDEWEB)

    Momeni, Mansour [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Saghafian, Hasan, E-mail: Saghafian@iust.ac.ir [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Center of Excellence for High Strength Alloys Technology (CEHSAT), Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Golestani-Fard, Farhad [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of); Barati, Nastaran; Khanahmadi, Amirhossein [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Adding SiO{sub 2} to N doped TiO{sub 2} films increased the band gap energy of the films. • SiO{sub 2} addition encouraged crack formation in N doped TiO{sub 2} thin films. • Addition of SiO{sub 2} weakened visible light activity and hydrophilicity of TiO{sub 2} films. • All films passed nanoscratch testing without detachment from the substrates. • Results propose using non-silica films on steel for application in visible light. - Abstract: Nanostructured N doped TiO{sub 2}/20%SiO{sub 2} thin films were developed on steel surface via sol gel method using a painting airbrush. Thin films then were calcined at various temperatures in a range of 400–600 °C. The effect of SiO{sub 2} addition on phase composition and microstructural evolution of N doped TiO{sub 2} films were studied using XRD and FESEM. Optical properties, visible light photocatalytic activity, hydrophilic behavior, and mechanical behavior of the films were also investigated by DRS, methylene blue degradation, water contact angle measurements, and nanoscratch testing. Results indicated that the band gap energy of N doped TiO{sub 2}/SiO{sub 2} was increased from 2.93 to 3.09 eV. Crack formation during calcination was also significantly promoted in the composite films. All composite films demonstrated weaker visible light photocatalytic activities and lower mechanical stability in comparison with N doped TiO{sub 2} films. Moreover, the N doped TiO{sub 2}/SiO{sub 2} film calcined at 600 °C showed undesirable hydrophilic behavior with a water contact angle of 57° after 31 h of visible light irradiation. Outcomes of the present study reveal some different results to previous reports on TiO{sub 2}/SiO{sub 2} films. In general, we believe the differences in substrate material as well as application in visible light are the main reasons for the above mentioned contradiction.

  2. Structural and magnetic properties of La0.7Sr0.3MnO3 ferromagnetic thin film grown on PMN-PT by sol–gel method

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2017-08-01

    Full Text Available We report the preparation of epitaxial La0.7Sr0.3MnO3 thin films grown on (001-oriented 0.72Pb(Mg1∕3Nb2∕3O3-0.28PbTiO3 substrates by the sol–gel technique. The phase structure, magnetic properties and magnetoresistance of the samples are investigated by using high solution X-ray diffraction, atomic force microscopy, physical property measurement system, respectively. The La0.7Sr0.3MnO3 thin films display a well-defined hysteresis loop and typical ferromagnetism behavior at lower temperature. High magnetoresistance at 5T of 42% appears at 227K for La0.7Sr0.3MnO3 thin film.

  3. Film

    OpenAIRE

    Jones, Sarah

    2002-01-01

    This book looks at the movie industry and at the labour intensive but fascinating process of making a feature film. It examines each stage in the production of a film, from initial idea through to the final cut and screening, and highlights the main activities that take place along the way. The book not only looks at the work of prominent people in the film world, such as directors and actors, but also describes the equally important but less high profile contributions of the gaffer, best boy...

  4. Preparation and studies of Eu{sup 3+} and Tb{sup 3+} co-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} sol-gel scintillating films

    Energy Technology Data Exchange (ETDEWEB)

    Morales Ramirez, A. de J, E-mail: amoralesra@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA) Unidad Altamira Instituto Politecnico Nacional Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Garcia Murillo, A.; Carrillo Romo, F. de J [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Ramirez Salgado, J. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas No. 152, CP 07730, Mexico D.F. (Mexico); Le Luyer, C. [LPCML, CNRS-UMR 5620/Universite Claude Bernard Lyon 1/69622 Villeurbanne Cedex (France); Chadeyron, G.; Boyer, D. [Laboratoire des Materiaux Inorganiques, CNRS-UMR 6002, Universite Blaise Pascal, 24 Ave des Landais F 63177 Aubiere Cedex (France); Moreno Palmerin, J. [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico)

    2009-10-30

    Eu{sup 3+} (2.5 at.%) and Tb{sup 3+} (0.005-0.01 at.%) co-doped gadolinium and yttrium oxide (Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3}) powders and films have been prepared using the sol-gel process. High density and optical quality thin films were prepared with the dip-coating technique. Gadolinium (III) 2,4-pentadionate and yttrium (III) 2,4-pentadionate were used as precursors, and europium and terbium in their nitrate forms were used as doping agents. Chemical and structural analyses (infrared spectroscopy, X-ray diffraction and high-resolution transmission electron microscopy) were conducted on both sol-gel precursor powders and dip-coated films. The morphology of thin films heat-treated at 700 {sup o}C was studied by means of atomic force microscopy. It was shown that the highly dense and very smooth films had a root mean roughness (RMS) of 2 nm {+-} 0.2 (A = 0.0075 Tb{sup 3+}) and 24 nm {+-} 3.0 (B = 0.01 Tb{sup 3+}). After treatment at 700 {sup o}C, the crystallized films were in the cubic phase and presented a polycrystalline structure made up of randomly oriented crystallites with grain sizes varying from 20 to 60 nm. The X-ray induced emission spectra of Eu{sup 3+}- and Tb{sup 3+}-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} powders showed that Tb{sup 3+} contents of 0.005, 0.0075 and 0.01 at.% affected their optical properties. Lower Tb{sup 3+} concentrations (down to 0.005 at.%) in both systems enhanced the light yield.

  5. Crystallization and electrical characteristics of ferroelectric Bi{sub 3.15}Nd{sub 0.85}Ti{sub 3}O{sub 12} thin films prepared by a sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Y. [Department of Physics, Jianghan University, Wuhan 430056 (China); Department of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Lu, C.J. [Department of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China)], E-mail: chaojing_lu@yahoo.com; Qi, Y.J. [Department of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Zhou, Y.H. [Department of Physics, Jianghan University, Wuhan 430056 (China)

    2008-07-01

    Ferroelectric Bi{sub 3.15}Nd{sub 0.85}Ti{sub 3}O{sub 12} (BNdT) thin films were deposited on Pt/Ti/SiO{sub 2}/Si substrates using a sol-gel process and Bi(NO{sub 3}){sub 3} was used as one of starting materials. Upon heating the major weight loss of the wet films occurred below 320 deg. C and nitrogen was almost completely removed at 650 deg. C. The films began to crystallize around 520 deg. C. The films annealed at 750 deg. C contain grains of 50-100 nm in diameter. The BNdT film capacitors with Pt top electrodes exhibited well-saturated hysteresis loops with a remanent polarization (2P{sub r}) of 57.4 {mu}C/cm{sup 2} and a coercive field of 108.3 kV/cm. The Pt/BNdT/Pt capacitors did not show any significant fatigue up to 6x10{sup 10} read/write switching cycles, and the retained charges remained nearly constant up to 10{sup 4} s after applying a writing pulse. The leakage current density of the BNdT films is less than 5x10{sup -8} A/cm{sup 2} under a low external field below 73 kV/cm.

  6. Film

    OpenAIRE

    Bould, M.

    2014-01-01

    A critical overview of critical-theoretical understandings of sf film, especially those promulgated by critics devoted to sf as a prose fiction form. It also considers adaptation, spectacle and special effects.

  7. Preparation and characterization of multi-walled carbon nanotube/hydroxyapatite nanocomposite film dip coated on Ti–6Al–4V by sol–gel method for biomedical applications: An in vitro study

    International Nuclear Information System (INIS)

    Abrishamchian, Alireza; Hooshmand, Tabassom; Mohammadi, Mohammadreza; Najafi, Farhood

    2013-01-01

    In the present research, the introduction of multi-walled carbon nanotubes (MWCNTs) into the hydroxyapatite (HA) matrix and dip coating of nanocomposite on titanium alloy (Ti–6Al–4V) plate was conducted in order to improve the performance of the HA-coated implant via the sol–gel method. The structural characterization and electron microscopy results confirmed well crystallized HA–MWCNT coating and homogenous dispersion of carbon nanotubes in the ceramic matrix at temperatures as low as 500 °C. The evaluation of the mechanical properties of HA and HA/MWCNT composite coatings with different weight percentages of MWCNTs showed that the addition of low concentrations of MWCNTs (0.5 and 1 wt.%) had improved effect on the mechanical properties of nanocomposite coatings. Moreover, this in vitro study ascertained the biocompatibility of the prepared sol–gel-derived HA/MWCNT composite coatings. - Highlights: ► Carbon nanotube/hydroxyapatite composite was successfully dip-coated on Ti by sol–gel. ► Well-crystallized HA–MWCNT and homogenous dispersion of nanotubes were obtained. ► Low concentration of CNTs improved the mechanical properties of composite coating. ► Biocompatibility of the prepared sol–gel-derived HA/MWCNT films was ascertained

  8. Accumulation of humic acid in DET/DGT gels

    Digital Repository Service at National Institute of Oceanography (India)

    Van der Veeken, P.L.R.; Chakraborty, P.; Van Leeuwen, H.P.

    in Thin film) that these natural complexing agents do enter the gel layer, and that humic acids even appear to accumulate in the gel, with enrichment factors typicallyonthe order of 10. The results have consequences for the interpretation of DGT...

  9. Production and characterization of LaMnO3 thin films prepared by Sol–Gel technique; Producción y caracterización de láminas delgadas de LaMnO3 preparadas por la técnica de Sol-Gel

    Energy Technology Data Exchange (ETDEWEB)

    Ebeoğlugil, M.F.

    2017-09-01

    In this study, lanthanum manganite (LaMnO3) thin films were prepared by sol-gel method for magnet technology. With this context, precursor solutions with low contact angles were synthesized from all nitrate salts of the respective cations (La, Mn), using ethanol as solvent and acetyl acetone as chelating agents. A dense amorphous film was deposited on silicon (Si) substrate. crystallization of the films was carried out at temperatures between 850 and 1000 °C. The thermal, phase, elemental, microstructural and magnetic properties of the obtained samples were determined by TG/DTA, FTIR, XRD, XPS, SEM and VSM. The results show that sustained perovskite polycrystalline films were grown on the [100]-oriented Si substrates. In addition, the films show ferromagnetic behavior. [Spanish] Se prepararon películas delgadas de manganita de lantano (LaMnO3) mediante el método Sol-gel para la tecnología del imán. Se sintetizaron soluciones precursoras con bajos ángulos de contacto a partir de sales de nitrato de los respectivos cationes (La, Mn), utilizando etanol como disolvente y acetil acetona como agente quelante. Se depositó una película amorfa y densa sobre sustrato de silicio (Si). La cristalización de las láminas se llevó a cabo a temperaturas entre 850 y 1000 ºC. El comportamiento térmico, especies químicas, microestructura y propiedades magnéticas se determinaron mediante TG / DTA, FTIR, XRD, XPS, SEM y VSM respectivamente. Los resultados muestran que láminas policristalinas de perovskita crecieron sobre los sustratos de Si orientados en el plano [100]. Finalmente, las láminas muestran un comportamiento ferromagnético.

  10. A simple approach of fabricating thermoelectric γ-NaxCoO2 and superconductive Nax(H2O)yCoO2-δ films using the sol-gel spin-coating method

    International Nuclear Information System (INIS)

    Liu, Chia-Jyi; Nayak, Pradipta K.; Chen, Yong-Zhi

    2009-01-01

    We report a simple approach of fabricating thermoelectric γ-Na x CoO 2 film with the c-axis orientation using the sol-gel spin-coating method. The inferred sodium content is x = 0.65 according to the correlation between the c-axis lattice constant and x. Temperature dependence of both the resistivity and thermopower resembles that of the γ-Na 0.68 CoO 2 film grown by the reactive solid-phase epitaxy. The fitted thermopower data show that the bandwidth of γ-Na x CoO 2 is found to be ∼ 101 meV, being close to the quasi-particle band (70-100 meV) derived from an angle-resolved photoemission study of γ-Na 0.7 CoO 2 . These results enable the possibility of low-cost fabrication of γ-Na x CoO 2 -based thermoelectric film devices. Furthermore, we have also topotactically transformed the of γ-Na x CoO 2 film to a superconducting Na x (H 2 O) y CoO 2-δ film with T c,onset = 4.12 K.

  11. Influences of the iron ion (Fe{sup 3+})-doping on structural and optical properties of nanocrystalline TiO{sub 2} thin films prepared by sol-gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Ben Naceur, J. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP.95, Hammam-Lif 2050 (Tunisia); Mechiakh, R., E-mail: raouf_mechiakh@yahoo.fr [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP.95, Hammam-Lif 2050 (Tunisia); Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar, Batna (Algeria); Bousbih, F.; Chtourou, R. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche des Sciences et Technologies de l' Energie, BP.95, Hammam-Lif 2050 (Tunisia)

    2011-10-01

    Titanium dioxide (TiO{sub 2}) thin films doping of various iron ion (Fe{sup 3+}) concentrations were deposited on silicon (Si) (100) and quartz substrates by sol-gel Spin Coating technique followed by a thermal treatment at 600 deg. C. The structure, surface morphology and optical properties, as a function of the doping, have been studied by X-ray diffractometer (XRD), Raman, ultraviolet-visible (UV-vis) and Spectroscopic Ellipsometry (SE). XRD and Raman analyzes of our thin films show that the crystalline phase of TiO{sub 2} thin films comprised only the anatase TiO{sub 2}, but the crystallinity decreased when the Fe{sup 3+} content increased from 0% to 20%. During the Fe{sup 3+} addition to 20%, the phase of TiO{sub 2} thin film still maintained the amorphous state. The grain size calculated from XRD patterns varies from 29.3 to 22.6 nm. The complex index and the optical band gap (E{sub g}) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreased with an increasing Fe{sup 3+} content.

  12. Impregnação de filmes do compósito de policarbonato (PC e sílicagel (Si com corante fotocrômico em fluido supercrítico = Impregnation of composite from polycarbonate (PC and silica gel (Si films with photochromic dye in supercritical fluid

    Directory of Open Access Journals (Sweden)

    Fernanda de Almeida Fin de Lima

    2010-01-01

    Full Text Available O objetivo deste trabalho foi estudar a impregnação do corante fotocromático Reversacol Graphit® em filmes do compósito de policarbonato (PC e sílica-gel (Si, com a finalidade de obter aplicações em lentes fotocrômicas. Filmes de PC puros também foramimpregnados nas mesmas condições, para verificar o efeito da adição de sílica-gel. Os filmes do compósito foram produzidos em proporções de Si:PC de 1:40 e 1:80 (m m-1, pelo método casting. Para a impregnação do corante Reversacol Graphit nos filmes obtidos foiutilizado o processo supercrítico, pela sua eficiência e benefícios. A impregnação foi feita nos tempos de 15, 30, 45, 60, 90, 120, 150 e 180 min. A temperatura e a pressão adotadas foram de 60ºC e 120 bar. A quantidade de pigmento impregnado nos filmes de Si:PC – 1:40e 1:80 (m m-1 foi de 29 e 23% de massa de corante por massa de compósito, respectivamente, e para o filme de PC puro foi de apenas 2,2% massa de corante por massa de compósito. Pelas análises térmicas, verificou-se que os filmes do compósito apresentarammaior estabilidade térmica. Pela técnica de microscopia eletrônica, observou-se que os filmes de PC puro e dos compósitos Si:PC – 1:40 e 1:80 (m m-1 apresentaram uma superfície lisa e homogênea.The aim of this work was to study the impregnation of the photochromic dye Reversacol Graphit® in composite films ofpolycarbonate (PC and silica gel, with the purpose of finding applications in photochromic lenses. Pure PC films were also impregnated in the same conditions, to verify the effect of the silica-gel addition. The composites films were produced in Si:PC ratios of 1:40 and 1:80 (m m-1, using the casting method . For the impregnation of the dye Reversacol Graphit in the obtained films, the supercritical process was used due to its efficiency and benefits. The impregnation was made in the times of 15, 30, 45, 60, 90, 120, 150 and 180 minutes. The adopted temperature and pressure

  13. Imprinted sol-gel electrochemical sensor for the determination of benzylpenicillin based on Fe{sub 3}O{sub 4}/SiO{sub 2} multi-walled carbon nanotubes-chitosans nanocomposite film modified carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Hu Yufang [College of Chemistry and Chemical Engineering, Jishou University, Hunan 416000 (China); Li Jiaxing [College of Chemistry and Chemical Engineering, Jishou University, Hunan 416000 (China); Central South University of Forestry and Technology, Hunan 410004 (China); Zhang Zhaohui, E-mail: zhaohuizhang77@163.com [College of Chemistry and Chemical Engineering, Jishou University, Hunan 416000 (China) and State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan 410082 (China); Zhang Huabin; Luo Lijuan [College of Chemistry and Chemical Engineering, Jishou University, Hunan 416000 (China); Yao Shouzhuo [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan 410082 (China)

    2011-07-18

    Graphical abstract: A novel imprinted sol-gel electrochemical sensor based on Fe{sub 3}O{sub 4}/SiO{sub 2}-MWNTs-CTS nanocomposite film and a thin MIP film has been developed on a carbon electrode. Highlights: {yields} A novel imprinted sol-gel electrochemical sensor based on Fe{sub 3}O{sub 4}/SiO{sub 2}-MWNTs-CTS nanocomposites has been developed. {yields} Fe{sub 3}O{sub 4}/SiO{sub 2}-MWNTs-CTS nanocomposites act as 'electronic wires' to enhance the electron transfer. {yields} The inherent specificity of the MIPs brings about highly selectivity. The imprinted sensor detects benzylpenicillin in real samples successfully. - Abstract: Herein, a novel imprinted sol-gel electrochemical sensor based on multi-walled carbon nanotubes (MWNTs) doped with chitosan film on a carbon electrode has been developed. Prior to doped, the MWNTs have been decorated with Fe{sub 3}O{sub 4} nanoparticles which have been coated uniformly with SiO{sub 2} layer. The characterization of imprinted sensor has been carried out by X-ray diffraction and scanning electron microscopy. The performance of the proposed imprinted sensor has been investigated using cyclic voltammetry and differential pulse voltammetry. The imprinted sensor offers a fast response and sensitive benzylpenicillin quantification. The fabricated benzylpenicillin imprinted sensor exhibits a linear response from 5.0 x 10{sup -8} to 1.0 x 10{sup -3} mol L{sup -1} with a detection limit of 1.5 x 10{sup -9} mol L{sup -1}. For samples analysis, perfect recoveries of the imprinted sensor for benzylpenicillin indicated that the imprinted sensor was able to detect benzylpenicillin in real samples successfully.

  14. Structure and Magnetic Properties of Y3−xErxFe5O12 (x=0.2,1.0, and 2.0 Thin Films Prepared by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Ramadan Shaiboub

    2011-01-01

    Full Text Available Nanoparticles Y3−xErxFe5O12 (x=0.2, 1.0, and 2.0 thin films were prepared by sol-gel method and treated at 800, 900, and 1000∘C, respectively, for 2 h. The films have single phase garnet structure and the sizes of particles are in the range of 44 to 83 nm. The magnetic measurements show that the saturation magnetization decreased with increasing of Er concentration for all samples treated at different annealing temperatures. The saturation magnetization increased with the particle size due to the enhancement of the surface spin effect. The coercivity initially decreased for x=1.0 and then increased for x=2.0 with increasing annealing temperature.

  15. Sol-Gel Synthesis and Characterization of Ba1-xGdxTiO3+δ Thin Films on SiO2/Si Substrates Using Spin-Coating Technique

    Directory of Open Access Journals (Sweden)

    Yen Chin TEH

    2017-02-01

    Full Text Available Ba1-xGdxTiO3+δ, at x = 0, 0.05, 0.1, 0.15, 0.2, (BGT thin films have been fabricated on SiO2/Si substrate using Sol-Gel method. The microstructure and surface morphology of the fabricated films have been investigated using X-ray diffraction (XRD and atomic force microscopy (AFM. The XRD results show that the fabricated films are crystalline with perovskite structure. There is a shifting of the preferred peak at 31.5o to a higher angle as the doping ratio increases suggesting a distortion lattice exists in the films, which could be due to the substitution of Gd3+ ions into Ba-site. The decreasing of lattice constants confirms the substitution of Gd3+ in BaTiO3 lattice structure. The microstrain and dislocation density are found to be increased with the increase of Gd3+ doping, which attributed to the reduction of lattice volume that due to the ionic size mismatch effect. The AFM results show decreasing trend in both average grain size and roughness parameters. Therefore, the microstructure and surface morphology of BGT samples is strongly dependent on the Gd3+ doping concentration that mainly due to the difference ionic radius substitution.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13954

  16. THE THICKNESS DEPENDENCE OF OXYGEN PERMEABILITY IN SOL-GEL DERIVED CGO-COFE2O4 THIN FILMS ON POROUS CERAMIC SUBSTRATES: A SPUTTERED BLOCKING LAYER FOR THICKNESS CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, K

    2009-01-08

    Mixed conductive oxides are a topic of interest for applications in oxygen separation membranes as well as use in producing hydrogen fuel through the partial oxidation of methane. The oxygen flux through the membrane is governed both by the oxygen ionic conductivity as well as the material's electronic conductivity; composite membranes like Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} (CGO)-CoFe{sub 2}O{sub 4} (CFO) use gadolinium doped ceria oxides as the ionic conducting material combined with cobalt iron spinel which serves as the electronic conductor. In this study we employ {approx} 50 nm sputtered CeO{sub 2} layers on the surface of porous CGO ceramic substrates which serve as solution 'blocking' layers during the thin film fabrication process facilitating the control of film thickness. Films with thickness of {approx} 2 and 4 microns were prepared by depositing 40 and 95 separate sol-gel layers respectively. Oxygen flux measurements indicated that the permeation increased with decreasing membrane thickness; thin film membrane with thickness on the micron level showed flux values an order of magnitude greater (0.03 {micro}mol/cm{sup 2} s) at 800 C as compared to 1mm thick bulk ceramic membranes (0.003 {micro}mol/cm{sup 2}).

  17. OPTICAL PROPERTIES OF Al:ZnO THIN FILM DEPOSITED BY DIFFERENT SOL-GEL TECHNIQUES: ULTRASONIC SPRAY PYROLYSIS AND DIP-COATING

    Directory of Open Access Journals (Sweden)

    Ebru Gungor

    2016-08-01

    Full Text Available Undoped and Al-doped ZnO polycrystalline thin films have been fabricated on glass substrates by using a computer-controlled dip coating (DC and ultrasonic spray pyrolysis (USP systems. The film deposition parameters of DC process were optimized for the samples. In this technique, the substrate was exposed to temperature gradient using a tube furnace. In the study, the other solvent-based technique was conventional USP. The zinc salt and Al salt concentrations in the solution were kept constant as 0.1 M and 2% of Zn salt’s molarity, respectively. The optical properties were compared for the films deposited two different techniques. The optical transmission of Al:ZnO/Glass/Al:ZnO sample dip coated and  the optical transmission of Al:ZnO/Glass sample ultrasonically sprayed were determined higher than 80% in the visible and near infrared region. Experimental optical transmittance spectra of the films in the forms of FilmA/Glass/FilmA and FilmA/glass were used to determine the optical constants. It was observed that the optical band gaps of Al doped ZnO films onto glass substrate were increases with increase of Al content and the absorption edge shifted to the shorter wavelength (blue shift compared with the undoped ZnO thin film.

  18. Film

    OpenAIRE

    Balint, Ruth; Dolgopolov, Greg

    2008-01-01

    From the beginning of the twentieth century, Sydney defined cosmopolitanism and modernity in the national imagination, and central to this image was the cinema: its technology, its architecture, its stars, its marketing and the stories it circulated to its audiences about Australia and the world. Though it is difficult to define a genre of Sydney film, Sydney provided the backdrop for a host of ideas about the city, and later suburbia. Sydney came to be seen as a ‘tinsel town’ of cultural ban...

  19. Spontaneous Pattern Formation Induced by Bénard-Marangoni Convection for Sol-Gel-Derived Titania Dip-Coating Films: Effect of Co-solvents with a High Surface Tension and Low Volatility.

    Science.gov (United States)

    Uchiyama, Hiroaki; Matsui, Tadayuki; Kozuka, Hiromitsu

    2015-11-17

    Evaporation-driven surface tension gradient in the liquid layer often causes the convective flow, i.e., Bénard-Marangoni convection, resulting in the formation of cell-like patterns on the surface. Here, we prepared sol-gel-derived titania films from Ti(OC3H7(i))4 solutions by dip coating and discussed the effect of the addition of co-solvents with a high surface tension and low volatility on the spontaneous pattern formation induced by Bénard-Marangoni convection. Propylene glycol (PG, with a surface tension of 38.6 mN m(-1)) and dipropylene glycol (DPG, with a surface tension of 33.9 mN m(-1)) were added to the coating solutions containing 2-propanol (2-Pr, with a surface tension of 22.9 mN m(-1)) for controlling the evaporation-driven surface tension gradient in the coating layer on a substrate. During dip coating at a substrate withdrawal speed of 50 cm min(-1) in a thermostatic oven at 60 °C, linearly arranged cell-like patterns on a micrometer scale were spontaneously formed on the titania gel films, irrespective of the composition of coating solutions. Such surface patterns remained even after the heat treatment at 200 and 600 °C, where the densification and crystallization of the titania films progressed. The width and height of the cell-like patterns increased with increasing PG and DPG contents in the coating solutions, where the addition of PG resulted in the formation of cells with a larger height than DPG.

  20. Waveguiding Er.sup.3+./sup./Yb.sup.3+./sup.:LiNbO.sub.3./sub. films prepared by a sol–gel method using polyvinylpyrrolidone

    Czech Academy of Sciences Publication Activity Database

    Rubešová, K.; Mikolášová, D.; Hlásek, T.; Jakeš, V.; Nekvindová, P.; Bouša, D.; Oswald, Jiří

    2016-01-01

    Roč. 176, Aug (2016), s. 260-265 ISSN 0022-2313 Institutional support: RVO:68378271 Keywords : lithium niobate * polyvinylpyrrolidone * erbium * sol –gel waveguide Subject RIV: BM - Sol id Matter Physics ; Magnetism Impact factor: 2.686, year: 2016

  1. Synthesis and optical characterization of C-SiO2 and C-NiO sol-gel composite films for use as selective solar absorbers

    CSIR Research Space (South Africa)

    Makiwa, G

    2008-08-01

    Full Text Available The authors present a cheaper and environmentally friendly method to fabricate efficient spectrally selective solar absorber materials. The sol-gel technique was used to fabricate carbon-silica (C-SiO2) and carbon-nickel oxide (C-NiO) composite...

  2. Use of the diffusive gradients in thin films technique (DGT) with various diffusive gels for characterization of sewage sludge-contaminated soils

    Czech Academy of Sciences Publication Activity Database

    Kovaříková, V.; Dočekalová, H.; Dočekal, Bohumil; Podborská, Martina

    2007-01-01

    Roč. 389, 7-8 (2007), s. 2303-2311 ISSN 1618-2642 Institutional research plan: CEZ:AV0Z40310501; CEZ:AV0Z50040702 Keywords : DGT * diffusive gels * soils Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.867, year: 2007

  3. Outdoor weathering of sol-gel-treated wood

    Science.gov (United States)

    Mandla A Tshabalala; Ryan Libert; Nancy Ross Sutherland

    2009-01-01

    Outdoor weathering of wood specimens treated with sol-gel formulations based on methyltrimethoxysilane (MTMOS), hexadecyltrimethoxysilane (HDTMOS), and ferric-zirconia-titania (Fe-Zr-Ti) sol was evaluated. The sol-gel process allowed deposition of a thin film of hybrid inorganic-organic networks (gel) in the wood cell wall that resulted in improved outdoor weathering...

  4. Thermoresponsive Gels

    OpenAIRE

    Taylor, M. Joan; Tomlins, P.; Sahota, T. S.

    2016-01-01

    An invited review and relates to the responsive gel used in the "artificial pancreas" work og INsmart, DMU. This article is an Open Access journal. Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others ...

  5. Effect of ion nitriding on the crystal structure of 3 mol% Y2O3-doped ZrO2 thin-films prepared by the sol-gel method

    International Nuclear Information System (INIS)

    Ortiz, A.L.; Diaz-Parralejo, A.; Borrero-Lopez, O.; Guiberteau, F.

    2006-01-01

    We investigated the effect of ion nitriding on the crystal structure of 3 mol% Y 2 O 3 -doped ZrO 2 (3YSZ) thin-films prepared by the sol-gel method. For this purpose, we used X-ray diffractometry to determine the crystalline phases, the lattice parameters, the crystal sizes, and the lattice microstrains, and glow discharge-optical emission spectroscopy to obtain the depth profiles of the elemental chemical composition. We found that nitrogen atoms substitute oxygen atoms in the 3YSZ crystal, thus leading to the formation of unsaturated-substitutional solid solutions with reduced lattice parameters and Zr 0.94 Y 0.06 O 1.72 N 0.17 stoichiometric formula. We also found that ion nitriding does not affect the grain size, but does generate lattice microstrains due to the increase in point defects in the crystalline lattice

  6. Ion-gel-gating-induced oxygen vacancy formation in epitaxial L a0.5S r0.5Co O3 -δ films from in operando x-ray and neutron scattering

    Science.gov (United States)

    Walter, Jeff; Yu, Guichuan; Yu, Biqiong; Grutter, Alexander; Kirby, Brian; Borchers, Julie; Zhang, Zhan; Zhou, Hua; Birol, Turan; Greven, Martin; Leighton, Chris

    2017-12-01

    Ionic-liquid/gel-based transistors have emerged as a potentially ideal means to accumulate high charge-carrier densities at the surfaces of materials such as oxides, enabling control over electronic phase transitions. Substantial gaps remain in the understanding of gating mechanisms, however, particularly with respect to charge carrier vs oxygen defect creation, one contributing factor being the dearth of experimental probes beyond electronic transport. Here we demonstrate the use of synchrotron hard x-ray diffraction and polarized neutron reflectometry as in operando probes of ion-gel transistors based on ferromagnetic L a0.5S r0.5Co O3 -δ . An asymmetric gate-bias response is confirmed to derive from electrostatic hole accumulation at negative gate bias vs oxygen vacancy formation at positive bias. The latter is detected via a large gate-induced lattice expansion (up to 1%), complementary bulk measurements and density functional calculations enabling quantification of the bias-dependent oxygen vacancy density. Remarkably, the gate-induced oxygen vacancies proliferate through the entire thickness of 30-40-unit-cell-thick films, quantitatively accounting for changes in the magnetization depth profile. These results directly elucidate the issue of electrostatic vs redox-based response in electrolyte-gated oxides, also demonstrating powerful approaches to their in operando investigation.

  7. Étude des matrices sol-gel en film mince par détection de molécule unique en champ large : diffusion moléculaire et agrégation photo-induite

    Science.gov (United States)

    Nutarelli, D.; Débarre, A.; Jaffiol, R.; Julien, C.; Richard, A.; Tchénio, P.; Chaput, F.; Boilot, J. P.

    2004-11-01

    La fluorescence de molécules de colorant dans des matrices sol-gel en film mince a été étudiée par détection de molécule unique. Outre les phénomènes de photo-blanchiment et de clignotement, un processus de photo-agrégation a été observé. Ce phénomène, dont la dynamique dépend de la présence d'oxygène, de l'intensité du laser d'excitation et de la température, montre l'existence de deux classes de molécules dans l'échantillon. Des molécules immobiles et d'autres qui diffusent. L'analyse de la dynamique d'agrégation permettra de dégager certaines caractéristiques du mécanisme de photo-agrégation et d'appréhender le rôle joué par la matrice sol-gel dans ce processus.

  8. Soft chemistry routes to transparent metal oxide thin films. The case of sol–gel synthesis and structural characterization of Ta2O5 thin films from tantalum chloromethoxide

    International Nuclear Information System (INIS)

    Epifani, Mauro; Zamani, Reza; Arbiol, Jordi; Fabrega, Cristian; Andreu, Teresa; Pace, Giovanni Battista; Siciliano, Pietro; Morante, Joan R.

    2014-01-01

    Ta 2 O 5 thin films were prepared by spin-coating methanol solutions of Ta chloromethoxide. It was prepared by reacting TaCl 5 with methanol, followed by water addition (H 2 O: Ta molar ratio was 16). Thin films were deposited by spin-coating onto SiO 2 /Si substrates, followed by drying at 90 °C and heat-treatment up to 700 °C. The films were characterized by X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. Crystallization was obtained only after heating at 700 °C, in the Ta 2 O 5 orthorhombic phase. The resulting films had a thickness of 100 nm. Their structure was constituted by porous crystals with size up to 50 nm, while the pores had a size of about 10 nm. The results demonstrated that TaCl 5 is very convenient precursor for the wet chemical synthesis of Ta 2 O 5 thin films. - Highlights: • Development of convenient solution synthesis of Ta 2 O 5 thin films; • The precursor chemistry was established and related to the synthesis process; • Uniform films crystallized in the most stable orthorombic Ta 2 O 5 phase;

  9. Surface grafted chitosan gels. Part II. Gel formation and characterization

    DEFF Research Database (Denmark)

    Liu, Chao; Thormann, Esben; Claesson, Per M.

    2014-01-01

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After...... detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross......-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels...

  10. In situ selective determination of methylmercury in river water by diffusive gradient in thin films technique (DGT) using baker's yeast (Saccharomyces cerevisiae) immobilized in agarose gel as binding phase

    Energy Technology Data Exchange (ETDEWEB)

    Tafurt-Cardona, Makenly [Programa de Pós-graduação em Geociências e Meio Ambiente, Instituto de Geociências e Ciências Exatas, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Centro de Estudos Ambientais, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Eismann, Carlos Eduardo; Suárez, Carlos Alfredo [Centro de Estudos Ambientais, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Menegário, Amauri Antonio, E-mail: amenega@rc.unesp.br [Programa de Pós-graduação em Geociências e Meio Ambiente, Instituto de Geociências e Ciências Exatas, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Centro de Estudos Ambientais, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Silva Luko, Karen [Programa de Pós-graduação em Geociências e Meio Ambiente, Instituto de Geociências e Ciências Exatas, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); Centro de Estudos Ambientais, UNESP – Univ. Estadual Paulista, Av. 24-A, 1515, CEP: 13506-900, Rio Claro, SP (Brazil); and others

    2015-08-05

    Saccharomyces cerevisiae immobilized in agarose gel as binding phase and polyacrylamide as diffusive layer in the diffusive gradient in thin films technique (DGT) was used for selective determination of methylmercury (MeHg). Deployment tests showed good linearity in mass uptake up to 48 h (3276 ng). When coupling the DGT technique with Cold Vapor Atomic Fluorescence Spectrometry, the method has a limit of detection of 0.44 ng L{sup −1} (pre concentration factor of 11 for 48 h deployment). Diffusion coefficient of 7.03 ± 0.77 × 10{sup −6} cm{sup 2} s{sup −1} at 23 °C in polyacrylamide gel (pH = 5.5 and ionic strength = 0.05 mol L{sup −1} NaCl) was obtained. Influence of ionic strength (from 0.0005 mol L{sup −1} to 0.1 mol L{sup −1} NaCl) and pH (from 3.5 to 8.5) on MeHg uptake were evaluated. For these range, recoveries of 84–105% and 84–98% were obtained for ionic strength and pH respectively. Potential interference due to presence of Cu, Fe, Mn, Zn was also assessed showing good recoveries (70–87%). The selectivity of the proposed approach was tested by deployments in solutions containing MeHg and Hg(II). Results obtained showed recoveries of 102–115 % for MeHg, while the uptake of Hg(II) was insignificant. The proposed approach was successfully employed for in situ measurements in the Negro River (Manaus-AM, Brazil). - Highlights: • A method for in situ selective determination of MeHg by DGT technique is proposed. • Saccharomyces cerevisiae immobilized in agarose gel was used as binding agent. • Effects of pH, ionic strength and concomitant ions on uptake of MeHg were evaluated. • DGT device containing polyacrylamide gel as diffusive layer showed better selectivity. • The proposed approach was successfully applied for analysis of river water.

  11. Thermoresponsive Gels

    Directory of Open Access Journals (Sweden)

    M. Joan Taylor

    2017-01-01

    Full Text Available Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others produce more counterintuitive responses to temperature change because of agglomeration induced by enthalpic or entropic drivers. Extensive covalent crosslinking superimposes complexity of response and the upper and lower critical solution temperatures can translate to critical volume temperatures for these swellable but insoluble gels. Their structure and volume response confer advantages for actuation though they lack robustness. Dynamic covalent bonding has created an intermediate category where shape moulding and self-healing variants are useful for several platforms. Developing synthesis methodology—for example, Reversible Addition Fragmentation chain Transfer (RAFT and Atomic Transfer Radical Polymerisation (ATRP—provides an almost infinite range of materials that can be used for many of these gelling systems. For those that self-assemble into micelle systems that can gel, the upper and lower critical solution temperatures (UCST and LCST are analogous to those for simpler dispersible polymers. However, the tuned hydrophobic-hydrophilic balance plus the introduction of additional pH-sensitivity and, for instance, thermochromic response, open the potential for coupled mechanisms to create complex drug targeting effects at the cellular level.

  12. A facile synthesis of mesoporous crystalline tin oxide films involving a base-triggered formation of sol–gel building blocks

    Czech Academy of Sciences Publication Activity Database

    Fried, D. I.; Ivanova, A.; Müller, V.; Rathouský, Jiří; Smarsly, B. M.; Fattakhova-Rohlfing, D.

    2011-01-01

    Roč. 3, č. 3 (2011), s. 1234-1239 ISSN 2040-3364 R&D Projects: GA ČR GA104/08/0435; GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40400503 Keywords : physical chemistry * evaporation -induced self-assembly * crystalline thin films Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.914, year: 2011

  13. Fabrication of undoped ZnO thin film via photosensitive sol–gel method and its applications for an electron transport layer of organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Luong, Chi Hieu [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Kim, Sarah [Central Research Division, LG Chem., Yuseong-gu, Daejeon 305-738 (Korea, Republic of); Surabhi, Srivathsava; Vo, Thanh Son; Lee, Kyung-Min; Yoon, Soon-Gil [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Jeong, Jun-Ho [Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Choi, Jun-Hyuk, E-mail: junhyuk@kimm.re.kr [Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Jeong, Jong-Ryul, E-mail: jrjeong@cnu.ac.kr [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2015-10-01

    Highlights: • Investigated the effect of the interfacial ZnO for ETL synthesized by photochemical reaction using photosensitive 2-nitrobenzaldehyde on the inverted P3HT:PCBM OSC. • The abrupt increase of grain size and surface roughness was observed as increasing the annealing temperature above 350 °C. • The sheet resistance abruptly decreased with increasing the annealing temperature above 350 °C. • Increase of surface roughness caused by the high annealing temperature could be detrimental to the OSCs characteristics due to a high contact resistance and a large leakage current. - Abstract: We have investigated ZnO thin films prepared via photochemical reaction as the electron transport layer (ETL) of inverted organic solar cells (OSCs). Morphological and electrical properties of the ZnO thin films prepared by the photosensitive ZnO sol were studied according to the annealing temperature and their effects on the performance of the inverted poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) OSCs was characterized. It was found that the optimal annealing temperature of the ZnO thin films was 330 °C, and that devices with the ZnO ETL annealed at this temperature exhibited the largest short-circuit current density (J{sub sc}) of 9.39 mA/cm{sup 2}, as well as the highest power conversion efficiency (PCE) of 2.31%, which can be attributed to enhanced electron transport and interfacial properties. Devices containing ZnO films formed at optimal annealing condition exhibited an open circuit voltage (V{sub oc}) of 0.60 V and a fill factor (FF) of 41.0%. However, further increase of the annealing temperature led to degradation of the device performance, despite further improvements in electrical properties. We have found that marked increase in the surface roughness of the ZnO films occurred at temperatures above 350 °C which could be detrimental to the OSCs characteristics due to a high contact resistance and a large leakage current.

  14. Synthesis Characterization and Photocatalytic Studies of Cobalt Ferrite-Silica-Titania Nanocomposites

    Science.gov (United States)

    Greene, David; Serrano-Garcia, Raquel; Govan, Joseph; Gun’ko, Yurii K.

    2014-01-01

    In this work, CoFe2O4@SiO2@TiO2 core-shell magnetic nanostructures have been prepared by coating of cobalt ferrite nanoparticles with the double SiO2/TiO2 layer using metallorganic precursors. The Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), Vibrational Sample Magnetometer (VSM) measurements and Raman spectroscopy results confirm the presence both of the silica and very thin TiO2 layers. The core-shell nanoparticles have been sintered at 600 °C and used as a catalyst in photo-oxidation reactions of methylene blue under UV light. Despite the additional non-magnetic coatings result in a lower value of the magnetic moment, the particles can still easily be retrieved from reaction mixtures by magnetic separation. This retention of magnetism was of particular importance allowing magnetic recovery and re-use of the catalyst. PMID:28344226

  15. Synthesis Characterization and Photocatalytic Studies of Cobalt Ferrite-Silica-Titania Nanocomposites

    Directory of Open Access Journals (Sweden)

    David Greene

    2014-04-01

    Full Text Available In this work, CoFe2O4@SiO2@TiO2 core-shell magnetic nanostructures have been prepared by coating of cobalt ferrite nanoparticles with the double SiO2/TiO2 layer using metallorganic precursors. The Transmission Electron Microscopy (TEM, Energy Dispersive X-Ray Analysis (EDX, Vibrational Sample Magnetometer (VSM measurements and Raman spectroscopy results confirm the presence both of the silica and very thin TiO2 layers. The core-shell nanoparticles have been sintered at 600 °C and used as a catalyst in photo-oxidation reactions of methylene blue under UV light. Despite the additional non-magnetic coatings result in a lower value of the magnetic moment, the particles can still easily be retrieved from reaction mixtures by magnetic separation. This retention of magnetism was of particular importance allowing magnetic recovery and re-use of the catalyst.

  16. Study of silica (Titania) aerogels using MYSANS at MINT 1 MW TRIGA reactor

    International Nuclear Information System (INIS)

    Abdul Aziz Mohamed; Faridah Mohd Idris; Razali Kassim

    2006-01-01

    Small angle neutron scattering (SANS) technique has been widely employed in probing the microstructure of amorphous materials in the nano structure range; 1-100 nm. In this study, SANS was used to study the structure of the silica aerogels with and without titania nanoparticles. In aerogel system, the size range of 1 to 100 nm is of particular interest since the structural units, such as the pores and particles often fall in this range. Data collected was consistent with present models for the structure of silica aerogels, and an increase in mass fractal dimension from 2.3 to 2.6 for titania containing aerogels was observed. Preliminary SANS data was collected using the MYSANS instrument on the MINT PUSPATI TRIGA reactor. The neutron beam has a wavelength of 0.5 nm. The sample in powder form had dimensions 18x37mm 2 and 2 mm path length. The complete data collection consists of three measurements: sample scattering, empty sample holder scattering, and detector dark current. The scattered neutrons were detected by a 128 x 128 array area sensitive detector, proportional counter (PSD). The resulting 2D patterns were reduced to 1D profiles for further analysis. Plots of intensity, I(Q) versus momentum transfer, Q, were derived. For comparison of this work, the samples had been analysed using BATAN SANS facility. This work has demonstrated that SANS facility at MINT, mySANS, is capable to provide information of fractal dimension. (Author)

  17. Enhanced Photocatalytic Activity for Degradation of Methyl Orange over Silica-Titania

    Directory of Open Access Journals (Sweden)

    Yaping Guo

    2011-01-01

    Full Text Available Silica-modified titania (SMT powders with different atomic ratios of silica to titanium (Rx were successfully synthesized by a simple ultrasonic irradiation technique. The prepared samples were characterized by X-ray diffraction (XRD, FT-IR spectroscopy, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and ultraviolet visible spectroscopy. The specific surface area was measured according to BET theory. Results indicate that the addition of silica to titania can suppress the crystalline size growth and the transformation of anatase phase to rutile phase of titania, enlarge specific surface area of the titania particles, and result in a blue shift of absorption edge compared to pure titania. The photocatalytic activity of the SMT samples was evaluated by decolorizing methyl orange aqueous solutions under UV-visible light irradiation. It was found in our study that this activity was affected by silica content, calcination temperature, H2SO4, and oxidants such as KIO4, (NH42S2O8 and H2O2. The results reveal that the photocatalytic activity of 0.1-SMT catalyst is the best among all samples calcined at 550°C for 1 h and it is 1.56 times higher than that of Degussa P-25 titania, which is a widely used commercial TiO2 made by Germany Degussa company and has been most widely used in industry as photocatalyst, antiultraviolet product, and thermal stabilizer. The optimal calcination temperature for preparation was 550°C. The photocatalytic activity of SMT samples is significantly enhanced by H2SO4 solution treatment and oxidants.

  18. Dense TiO2 films grown by sol–gel dip coating on glass, F-doped SnO2, and silicon substrates

    Czech Academy of Sciences Publication Activity Database

    Procházka, Jan; Kavan, Ladislav; Zukalová, Markéta; Janda, Pavel; Jirkovský, Jaromír; Vlčková Živcová, Zuzana; Poruba, A.; Bedu, M.; Döbbelin, M.; Tena-Zaera, R.

    2013-01-01

    Roč. 28, č. 3 (2013), s. 385-393 ISSN 0884-2914 R&D Projects: GA AV ČR IAA400400804; GA AV ČR KAN200100801; GA ČR(CZ) GAP108/12/0814 Grant - others:OpenAIRE(XE) EC 7th FP project SANS, NMP-246124; Open AIRE(XE) EC 7th FP projekt ORION , NMP-229036 Institutional support: RVO:61388955 Keywords : titanium dioxide * thin films * silicon Subject RIV: CG - Electrochemistry Impact factor: 1.815, year: 2013

  19. Synthesis and characterization of erbium-doped SiO{sub 2}-TiO{sub 2} thin films prepared by sol-gel and dip-coating techniques onto commercial glass substrates as a route for obtaining active GRadient-INdex materials

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Varela, Ana I. [Microoptics and GRIN Optics Group, Department of Applied Physics, Faculty of Optics and Optometry and Faculty of Physics, Universidade de Santiago de Compostela, Campus Vida s/n, Santiago de Compostela E-15782 (Spain); Castro, Yolanda, E-mail: castro@icv.csic.es [Instituto de Cerámica y Vidrio (CSIC), Kelsen 5, Campus de Cantoblanco, Madrid 28049 (Spain); Durán, Alicia [Instituto de Cerámica y Vidrio (CSIC), Kelsen 5, Campus de Cantoblanco, Madrid 28049 (Spain); De Beule, Pieter A.A. [Applied Nano-Optics Laboratory, International Iberian Nanotechnology Laboratory, Braga 4715-330 (Portugal); Flores-Arias, María T. [Microoptics and GRIN Optics Group, Department of Applied Physics, Faculty of Optics and Optometry and Faculty of Physics, Universidade de Santiago de Compostela, Campus Vida s/n, Santiago de Compostela E-15782 (Spain); Bao-Varela, Carmen, E-mail: carmen.bao@usc.es [Microoptics and GRIN Optics Group, Department of Applied Physics, Faculty of Optics and Optometry and Faculty of Physics, Universidade de Santiago de Compostela, Campus Vida s/n, Santiago de Compostela E-15782 (Spain)

    2015-05-29

    In this work, SiO{sub 2}-TiO{sub 2} films doped with erbium were prepared by dip-coating sol-gel process onto commercial glass substrates. The surface morphology of the films was characterized using atomic force microscopy, while thickness, refractive index, extinction coefficient and porosity of the films were determined by ellipsometric measurements in a wavelength region of 400-1000 nm. Optical constants and porosity were found to vary with erbium concentration. The proof of principle presented in this paper is applicable to systems of different nature by tailoring the sol-gel precursors in such a way that active GRadient-INdex media described by a complex, parabolic-like refractive index distribution for beam shaping purposes is obtained. - Highlights: • Sol-gel route for preparation of active GRadient-INdex materials is proposed. • SiO{sub 2}-TiO{sub 2} films doped with erbium were prepared by dipping onto commercial glasses. • Morphological and optical characterization of the samples was performed. • Optical constants and porosity were found to vary with erbium concentration. • Refractive index diminishes with dopant content; the contrary occurs for porosity.

  20. Design a sensitive optical thin film sensor based on incorporation of isonicotinohydrazide derivative in sol-gel matrix for determination of trace amounts of copper (II) in fruit juice: Effect of sonication time on immobilization approach.

    Science.gov (United States)

    Shahamirifard, Seyed Alireza; Ghaedi, Mehrorang; Montazerozohori, Morteza

    2018-04-01

    A new selective and sensitive optical sensor based on the incorporation of new synthesized N'-(2-hydroxy-5-iodobenzylidene) isonicotinohydrazide (HIBIN) as an effective reagent into the nanoporous of a transparent glass like material through the sol-gel process was developed which was suitable for the determination of copper (II) ions in aqueous solutions. The thin film sensors were constructed by spin-coating of prepared sol onto glass plate and their surface morphology were studied by field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM) technique. Influence of sonication time on immobilization of HIBIN into silica matrix was investigated through calculation of leaching percentage. The Results shown that sonication time of 35 min is suitable to give more stable thin films without fluctuation in sensitivity and response time of presented sensor for a long period of time. The proposed optical sensor can be used for determination of copper (II) ions in the range of 9.1 × 10 -8 -1.12 × 10 -5  mol L -1 with a detection limit of 1.8 × 10 -8  mol L -1 . It also showed relative standard deviation 3.4 and 0.72% for reproducibility and repeatability respectively, along with a fast response time about of 2 min. The constructed optode is stable in wet conditions and could be stored for at least 6 weeks without observing any change in its sensitivity. The developed sensor was successfully applied to the determination of copper (II) in fruit juice and water samples which results were confirmed by atomic absorption spectrometry method. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Effect of Mn-Site for Al Substitution on Structural, Electrical and Magnetic Properties in La0.67Sr0.33Mn1-xAlxO3 Thin Films by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    H. Abdullah

    2014-01-01

    Full Text Available Nanocrystalline La0.67Sr0.33Mn1-xAlxO3 (x=0.00, 0.05, 0.10, 0.15, 0.20, and 0.25 thin films have been prepared on quartz substrates by sol-gel method. The structural and morphology studies were investigated via X-ray diffraction (XRD and field emission scanning electron microscope (FESEM. XRD graph patterns show rhombohedral distorted perovskite structures. FESEM images show that the average grain size decreased as the concentration of x increased. Electrical property was investigated using four-point probe technique. Resistivity results show that metal-insulator transition (MIT temperatures (Tp decreased when the concentration of x increased. Tp shifted to lower temperature when the concentration of x increased. The data was analyzed based on theoretical models, where the ferromagnetic resistivity is followed with the equation ρ=ρo+ρ2T2, where ρo is due to the significance of grain boundary effects and a second-term ~ρ2T2 appears that might be applied to the electrons scattering. In the high temperature regime (T>Tp, the resistivity data can be well described by small polaron hopping (SPH and variable range hopping (VRH mechanisms. Magnetic property was investigated using a vibration sample magnetometer. All samples that were obtained showed hysteresis curve with the highest value of magnetization for sample x=0.10.

  2. Preparation and corrosion resistance studies of nanometric sol-gel-based CeO{sub 2} film with a chromium-free pretreatment on AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shiyan [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Li Qing, E-mail: liqingswu@yeah.ne [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chen Bo [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yang Xiaokui [School of Materials Science and Engineering, Southwest University, Chongqing 400715 (China)

    2010-01-01

    Magnesium alloy, although valuable, is reactive and requires protection before it can be applied in many fields. In this study, a novel protective environmental-friendly gradient coating was performed on AZ91D magnesium alloy by non-chromate surface treatments, which consisted of phytic acid chemical conversion coating and the sol-gel-based CeO{sub 2} thin film. The surface morphologies, microstructure and composition of the coatings were investigated by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The corrosion resistance of the coatings was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. The effects of the concentration, layers, temperature of heat treatment of CeO{sub 2} sol on the anti-corrosion properties of the gradient coating for magnesium were also investigated. The results showed that the gradient coating was mainly composed of crystalline CeO{sub 2}. According to the results of electrochemical tests, the corrosion resistance of AZ91D magnesium alloy was found to be greatly improved by means of this new environmental-friendly surface treatment.

  3. 1T1R Nonvolatile Memory with Al/TiO₂/Au and Sol-Gel-Processed Insulator for Barium Zirconate Nickelate Gate in Pentacene Thin Film Transistor.

    Science.gov (United States)

    Lee, Ke-Jing; Chang, Yu-Chi; Lee, Cheng-Jung; Wang, Li-Wen; Wang, Yeong-Her

    2017-12-09

    A one-transistor and one-resistor (1T1R) architecture with a resistive random access memory (RRAM) cell connected to an organic thin-film transistor (OTFT) device is successfully demonstrated to avoid the cross-talk issues of only one RRAM cell. The OTFT device, which uses barium zirconate nickelate (BZN) as a dielectric layer, exhibits favorable electrical properties, such as a high field-effect mobility of 5 cm²/Vs, low threshold voltage of -1.1 V, and low leakage current of 10 -12 A, for a driver in the 1T1R operation scheme. The 1T1R architecture with a TiO₂-based RRAM cell connected with a BZN OTFT device indicates a low operation current (10 μA) and reliable data retention (over ten years). This favorable performance of the 1T1R device can be attributed to the additional barrier heights introduced by using Ni (II) acetylacetone as a substitute for acetylacetone, and the relatively low leakage current of a BZN dielectric layer. The proposed 1T1R device with low leakage current OTFT and excellent uniform resistance distribution of RRAM exhibits a good potential for use in practical low-power electronic applications.

  4. Tuning of Ag-SPR band position in refractive index controlled ...

    Indian Academy of Sciences (India)

    Inorganic (silica-titania)-organic (polyethylene oxide) hybrid films with variable refractive index (RI) values were synthesized and Ag nanoparticles were generated in situ inside such hybrid films to develop coloured coatings specially on plastic substrates. The hybrid films and the corresponding Agincorporated films were ...

  5. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Inorganic (silica-titania)-organic (polyethylene oxide) hybrid films with variable refractive index (RI) values were synthesized and Ag nanoparticles were generated in situ inside such hybrid films to develop coloured coatings specially on plastic substrates. The hybrid films and the corresponding Agincorporated films were ...

  6. Radiotherapy gel dosimetry

    International Nuclear Information System (INIS)

    Baldock, C.

    2002-01-01

    shapes and sizes while sparing normal tissue. The situation is further complicated if the normal tissues are critical organs or are particularly sensitive to radiation. Radiotherapy techniques employed to obtain a closer conformation of the dose distribution to the tumour volume are referred to as conformal radiotherapy techniques. The clinical implementation of conformal therapy has been delayed by limitations in the verification of conformal dose distributions calculated by treatment planning systems prior to the irradiation of the patient and the verification of complex treatments during its delivery to the patient. There are several aspects of conformal therapy that complicate dose verification. To achieve the dose distributions conforming to complex 3D volumes, high dose gradients arise in the treatment volume. Further, overdose or underdose regions can exist when separate radiation fields are used to deliver additional radiation. These aspects require that practical dose measurement (dosimetry) techniques be able to integrate dose over time and easily measure dose distributions in 3D with high spatial resolution. Traditional dosimeters, such as ion chambers, thermoluminescent dosimeters and radiographic film do not fulfil these requirements. Novel gel dosimetry techniques are being developed in which dose distributions can potentially be determined in vitro in 3D using anthropomorphic phantoms to simulate a clinically irradiated situation. As long ago as the 1950's, radiation-induced colour change in dyes was used to investigate radiation doses in gels. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured using magnetic resonance imaging (MRI). In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin, agarose or PVA matrix. Radiation-induced changes in the dosimeters are considered to

  7. The Sol-Gel-Xerogel Transition

    Science.gov (United States)

    1993-11-01

    relative mobili- ty are supported by the ESR (Electron Spin Resonance) studies of * * * Ikoma et al. [301 demonstrating that polyamine copper(II) chelates...deactivation of the triplet state of the molecule in the case of RTP. Recent studies on the photoisomerization of azobenzene in sol-gel glass films by

  8. Sol-gel bonding of silicon wafers

    International Nuclear Information System (INIS)

    Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Short, K.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

    2005-01-01

    Sol-gel bonds have been produced between smooth, clean silicon substrates by spin-coating solutions containing partially hydrolysed silicon alkoxides. The two coated substrates were assembled and the resulting sandwich fired at temperatures ranging from 60 to 600 deg. C. The sol-gel coatings were characterised using attenuated total reflectance Fourier transform infrared spectroscopy, ellipsometry, and atomic force microscopy, while the corresponding bonded specimens were investigated using scanning electron microscopy and cross-sectional transmission electron microscopy. Mechanical properties were characterised using both microindentation and tensile testing. Bonding of silicon wafers has been successfully achieved at temperatures as low as 60 deg. C. At 300 deg. C, the interfacial fracture energy was 1.55 J/m 2 . At 600 deg. C, sol-gel bonding provided superior interfacial fracture energy over classical hydrophilic bonding (3.4 J/m 2 vs. 1.5 J/m 2 ). The increase in the interfacial fracture energy is related to the increase in film density due to the sintering of the sol-gel interface with increasing temperature. The superior interfacial fracture energy obtained by sol-gel bonding at low temperature is due to the formation of an interfacial layer, which chemically bonds the two sol-gel coatings on each wafer. Application of a tensile stress on the resulting bond leads to fracture of the samples at the silicon/sol-gel interface

  9. Tuning of Ag-SPR band position in refractive index controlled ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Inorganic (silica-titania)–organic (polyethylene oxide) hybrid films with variable refractive index (RI) values were synthesized and Ag nanoparticles were generated in situ inside such hybrid films to develop coloured coatings specially on plastic substrates. The hybrid films and the corresponding Ag- incorporated ...

  10. Removing water from gels

    International Nuclear Information System (INIS)

    Lane, E.S.; Winter, J.A.

    1982-01-01

    Water is removed from a gel material by contacting the gel material with an organic liquid and contacting the organic liquid with a gas such that water is taken up by the gas. The invention, in one embodiment, may be used to dry gel materials whilst maintaining an open porous network therein. In one example, the invention is applied to gel precipitated spheres containing uranium and plutonium. (author)

  11. Polymer gels and networks

    National Research Council Canada - National Science Library

    Osada, Yoshihito; Khokhlov, A. R

    2002-01-01

    ... or magnetic field, etc.). It was realized that not only can polymer gels absorb and hold a considerable volume of liquids, but they can also be forced to expel the absorbed liquid in a controlled manner. Of particular interest are hydrogels, i.e., polymer gels, which swell extensively in water. The most common hydrogels are polyelectrolyte gels: ...

  12. Preparation, patterning and luminescent properties of oxyapatite La sub 9 sub . sub 3 sub 3 (SiO sub 6) sub 4 O sub 2 :A(A = Eu sup 3 sup + , Tb sup 3 sup + , Ce sup 3 sup +) phosphor films by sol-gel soft lithography

    CERN Document Server

    Han, X M; Xing, R B; Fu, J; Wang, S B; Han, Y C

    2003-01-01

    Silicate oxyapatite La sub 9 sub . sub 3 sub 3 (SiO sub 6) sub 4 O sub 2 :A (A = Eu sup 3 sup + , Tb sup 3 sup + and/or Ce sup 3 sup +) phosphor films and their patterning were fabricated by a sol-gel process combined with soft lithography. X-ray diffraction(XRD), Fourier transform infrared spectroscopy, atomic force microscopy, optical microscopy and photoluminescence spectra, as well as lifetimes, were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 800 deg. C and the crystallinity increased with the increase in annealing temperatures. Transparent nonpatterned phosphor films were uniform and crack-free, which mainly consisted of rodlike grains with a size between 150 and 210 nm. Patterned thin films with different bandwidths(20, 50 mu m) were obtained by the micromoulding in capillaries technique. The doped rare earth ions(Eu sup 3 sup + , Tb sup 3 sup + and Ce sup 3 sup +) showed their characteristic emission in crystalline La sub 9 sub . sub 3 ...

  13. Transport Phenomena in Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  14. Impregnação de filmes do compósito de policarbonato (PC e sílica-gel (Si com corante fotocrômico em fluido supercrítico - DOI: 10.4025/actascitechnol.v32i1.1999

    Directory of Open Access Journals (Sweden)

    Fernanda de Almeida Fin de Lima

    2009-12-01

    Full Text Available O objetivo deste trabalho foi estudar a impregnação do corante fotocromático Reversacol Graphit® em filmes do compósito de policarbonato (PC e sílica-gel (Si, com a finalidade de obter aplicações em lentes fotocrômicas. Filmes de PC puros também foram impregnados nas mesmas condições, para verificar o efeito da adição de sílica-gel. Os filmes do compósito foram produzidos em proporções de Si:PC de 1:40 e 1:80 (m m-1, pelo método casting. Para a impregnação do corante Reversacol Graphit® nos filmes obtidos foi utilizado o processo supercrítico, pela sua eficiência e benefícios. A impregnação foi feita nos tempos de 15, 30, 45, 60, 90, 120, 150 e 180 min. A temperatura e a pressão adotadas foram de 60ºC e 120 bar. A quantidade de pigmento impregnado nos filmes de Si:PC – 1:40 e 1:80 (m m-1 foi de 29 e 23% de massa de corante por massa de compósito, respectivamente, e para o filme de PC puro foi de apenas 2,2% massa de corante por massa de compósito. Pelas análises térmicas, verificou-se que os filmes do compósito apresentaram maior estabilidade térmica. Pela técnica de microscopia eletrônica, observou-se que os filmes de PC puro e dos compósitos Si:PC – 1:40 e 1:80 (m m-1 apresentaram uma superfície lisa e homogênea.

  15. Sol-Gel Glasses

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  16. GelTouch

    DEFF Research Database (Denmark)

    Miruchna, Viktor; Walter, Robert; Lindlbauer, David

    2015-01-01

    We present GelTouch, a gel-based layer that can selectively transition between soft and stiff to provide tactile multi-touch feedback. It is flexible, transparent when not activated, and contains no mechanical, electromagnetic, or hydraulic components, resulting in a compact form factor (a 2mm thin...... touchscreen layer for our prototype). The activated areas can be morphed freely and continuously, without being limited to fixed, predefined shapes. GelTouch consists of a poly(N-isopropylacrylamide) gel layer which alters its viscoelasticity when activated by applying heat (>32 C). We present three different...

  17. Transport Phenomena in Gel

    OpenAIRE

    Masayuki Tokita

    2016-01-01

    Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilu...

  18. Effects of thermal treatment conditions on the phase formation and the morphological changes of sol-gel derived 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 thin films

    International Nuclear Information System (INIS)

    Yang, Sun A; Han, Jin Kyu; Choi, Yong Chan; Bu, Sang Don

    2011-01-01

    We report the synthesis of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) thin films and the effects of thermal conditions on their surface morphologies and phase formation behaviors. The PMN-PT thin films were prepared by spin-coating PMN-PT sol-gel solutions on Pt/Ti/SiO 2 /Si substrates and subsequent thermal treatments including pyrolysis, annealing, and additional pre-annealing. We found that the surface morphologies and the formation of the perovskite phase were strongly affected by the final annealing temperature. The grain size of perovskite phase and the amount of the perovskite phase increased as the annealing temperature was increased from 550 to 800 .deg. C. We also found that the voids started to form on the surface of the film at an annealing temperature of 650 .deg. C and that their areas increased with increasing in annealing temperature. The void formation was found to depend on the time period of pyrolysis and on the pre-annealing process between pyrolysis and final annealing. Dense PMN-PT films with relatively high amounts of the perovskite phase were obtained when additional pre-annealing at 750 .deg. C for 5 min was performed.

  19. Cyanocobalamin Nasal Gel

    Science.gov (United States)

    ... to supply extra vitamin B12 to people who need unusually large amounts of this vitamin because they are pregnant or have certain diseases. ... Cyanocobalamin nasal gel will supply you with enough vitamin B12 only as ... it regularly. You may need to use cyanocobalamin nasal gel every week for ...

  20. Modeling chemoresponsive polymer gels.

    Science.gov (United States)

    Kuksenok, Olga; Deb, Debabrata; Dayal, Pratyush; Balazs, Anna C

    2014-01-01

    Stimuli-responsive gels are vital components in the next generation of smart devices, which can sense and dynamically respond to changes in the local environment and thereby exhibit more autonomous functionality. We describe recently developed computational methods for simulating the properties of such stimuli-responsive gels in the presence of optical, chemical, and thermal gradients. Using these models, we determine how to harness light to drive shape changes and directed motion in spirobenzopyran-containing gels. Focusing on oscillating gels undergoing the Belousov-Zhabotinksy reaction, we demonstrate that these materials can spontaneously form self-rotating assemblies, or pinwheels. Finally, we model temperature-sensitive gels that encompass chemically reactive filaments to optimize the performance of this system as a homeostatic device for regulating temperature. These studies could facilitate the development of soft robots that autonomously interconvert chemical and mechanical energy and thus perform vital functions without the continuous need of external power sources.

  1. Sol-Gel Production; Proceedings of the First International Conference on Application and Commercialization of Sol-Gel Processing Held in Saarbruecken, Germany on 24-25 May 1993

    National Research Council Canada - National Science Library

    Schmidt, Helmut

    1998-01-01

    ...; Sol-Gel Coatings on Large Glass Substrates for Multilayer Interference Systems; A SiO2-ZrO2 Gel Film doped with Organic Pigments Made by the Sol-Gel Method for Contrast Enhancement of Color Picture Tubes...

  2. Fabrication of high quality Cu2SnS3 thin film solar cell with 1.12% power conversion efficiency obtain by low cost environment friendly sol-gel technique

    Science.gov (United States)

    Chaudhari, J. J.; Joshi, U. S.

    2018-03-01

    Cu2SnS3 (CTS) is an emerging ternery chalcogenide material with great potential application in thin film solar cells. We present here high quality Cu2SnS3 thin films using a facile spin coating method. The as deposited films of CTS were sulphurized in a graphite box using tubular furnace at 520 °C for 60 min at the rate of 2.83 °C min-1 in argon atmosphere. X-ray diffraction (XRD) and Raman spectroscopy studies confirm tetragonal phase and absence of any secondary phase in sulphurized CTS thin films. X-ray photoelectron spectroscopy (XPS) demonstrates that Cu and Sn are in +1 and +4 oxidation state respectively. Surface morphology of CTS films were analyzed by field emission scanning electron microscope and atomic force microscope (AFM), which revealed a smooth surface with roughness (RMS) of 6.32 nm for sulphurized CTS film. Hall measurements confirmed p-type conductivity with hole concentartion of sulphurized CTS thin film is of 6.5348 × 1020 cm-3. UV-vis spectra revealed a direct energy band gap varies from 1.45 eV to 1.01 eV for as-deposited and sulphurized CTS thin film respectively. Such band gap values are optimum for semiconductor material as an absorber layer of thin film solar cell. The CTS thin film solar cell had following structure: SLG/FTO/ZnO/CTS/Al with short circuit current density of (Jsc) of 11.6 mA cm-2, open circuit voltage (Voc) of 0.276 V, active area of 0.16 cm2, fill factor (FF) of 35% and power conversion efficiency of 1.12% under AM 1.5 (100 mW cm-2) illumination in simulated standard test conditions.

  3. Quantitative comparison between the gel-film and polyvinyl alcohol methods for dehydrogenase histochemistry reveals different intercellular distribution patterns of glucose-6-phosphate and lactate dehydrogenases in mouse liver

    NARCIS (Netherlands)

    Griffini, P.; Vigorelli, E.; Bertone, V.; Freitas, I.; van Noorden, C. J.

    1994-01-01

    The precise histochemical localization and quantification of the activity of soluble dehydrogenases in unfixed cryostat sections requires the use of tissue protectants. In this study, two protectants, polyvinyl alcohol (PVA) and agarose gel, were compared for assaying the activity of lactate

  4. Periodic mesoporous silica gels

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, M.T.; Martin, J.E.; Odinek, J.G. [and others

    1996-06-01

    We have synthesized monolithic particulate gels of periodic mesoporous silica by adding tetramethoxysilane to a homogeneous alkaline micellar precursor solution. The gels exhibit 5 characteristic length scales over 4 orders of magnitude: fractal domains larger than the particle size (>500 nm), particles that are {approximately}150 to 500 nm in diameter, interparticle pores that are on the order of the particle size, a feature in the gas adsorption measurements that indicates pores {approximately}10-50 nm, and periodic hexagonal arrays of {approximately}3 nm channels within each particle. The wet gel monoliths exhibit calculated densities as low as {approximately}0.02 g/cc; the dried and calcined gels have bulk densities that range from {approximately}0.3-0.5 g/cc. The materials possess large interparticle ({approximately}1.0-2.3 cc/g) and intraparticle ({approximately}0.6 cc/g) porosities.

  5. Gel purification of RNA.

    Science.gov (United States)

    Nilsen, Timothy W

    2013-02-01

    For many applications, including size selection of RNAs and purification of in vitro transcription products, it is necessary to purify RNAs on a denaturing gel. This procedure describes how to purify transcripts that have been synthesized in vitro. It is useful for labeled or unlabeled RNAs when sufficient mass is present. It can also be used to isolate small RNAs. In general, RNA purification by denaturing gel electrophoresis is practical only when the size of the desired RNA is 600 nucleotides or less.

  6. Conformance Improvement Using Gels

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall S.; Schrader, Richard; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Gary, Raven; Marin; Amaury; Lindquist, Brent

    2002-09-26

    This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

  7. Sol-gel processes and materials. January 1970-August 1988 (Citations from the US Patent data base). Report for January 1970-August 1988

    International Nuclear Information System (INIS)

    1988-08-01

    This bibliography contains citations of selected patents concerning Sol-Gel processes and Sol-Gel derived materials and products. Selected patents include Sol-Gel compositions, ceramic and refractory materials, fabrication of silica glass, cataylsts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, Sol-Gel production of microspheres, Sol-Gel thin films and coatings, photographic materials, and dental materials. (Contains 71 citations fully indexed and including a title list.)

  8. Preparation and characterization of multi-walled carbon nanotube/hydroxyapatite nanocomposite film dip coated on Ti-6Al-4V by sol-gel method for biomedical applications: an in vitro study.

    Science.gov (United States)

    Abrishamchian, Alireza; Hooshmand, Tabassom; Mohammadi, Mohammadreza; Najafi, Farhood

    2013-05-01

    In the present research, the introduction of multi-walled carbon nanotubes (MWCNTs) into the hydroxyapatite (HA) matrix and dip coating of nanocomposite on titanium alloy (Ti-6Al-4V) plate was conducted in order to improve the performance of the HA-coated implant via the sol-gel method. The structural characterization and electron microscopy results confirmed well crystallized HA-MWCNT coating and homogenous dispersion of carbon nanotubes in the ceramic matrix at temperatures as low as 500 °C. The evaluation of the mechanical properties of HA and HA/MWCNT composite coatings with different weight percentages of MWCNTs showed that the addition of low concentrations of MWCNTs (0.5 and 1 wt.%) had improved effect on the mechanical properties of nanocomposite coatings. Moreover, this in vitro study ascertained the biocompatibility of the prepared sol-gel-derived HA/MWCNT composite coatings. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Surface modification of wood by alkoxysilane sol-gel deposition to create anti-mold and anti-fungal characteristics

    Science.gov (United States)

    Mandla A. Tshabalala; Vina Yang; Ryan Libert

    2009-01-01

    Hybrid inorganic/organic thin films deposited on wood substrates have been shown to lower the rate of moisture sorption of the wood. Deposition of such thin films can be accomplished by sol–gel deposition or by plasma-enhanced chemical vapor deposition. This paper describes in situ sol–gel deposition of hybrid inorganic/organic thin films on wood substrates using...

  10. Photocatalytic and Adsorptive System for Odor Control in Lunar Surface Systems Using Silica-Titania Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work herein focuses on waste subsystems with emphasis on odor control associated with volatile organic compounds (VOCs). The development of efficient...

  11. Photocatalytic and Adsorptive System for Odor Control in Lunar Surface Systems Using Silica-Titania Composites, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The work proposed herein focuses on waste subsystems with emphasis on odor control associated with volatile organic compounds (VOCs). The development of efficient...

  12. Analyses of laser and furnace treated sol-gel coatings

    NARCIS (Netherlands)

    De Hosson, JT; De Haas, M; Sudarshan, TS; Jeandin, M; Khor, KA

    1998-01-01

    Here we explore a new method that allows thin films to be made with almost any composition and degree of porosity by means of a combination of sol-gel and laser technology. Results are presented for furnace and laser treated TEOTI-(tetraethylorthotitanate as sol precursor) coated silicon samples.

  13. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  14. Extractable protein content of radiation vulcanized natural rubber latex films

    International Nuclear Information System (INIS)

    Ma'zam Md Said; Wan Manshol Wan Zin

    1996-01-01

    The effects of processing conditions on extractable protein content of coagulant dipped radiation vulcanized natural rubber latex films have been investigated. Drying of wet-gel of radiation vulcanized latex films even at a relatively low temperature of 70 degree C resulted in increases of extractable protein content of the films. The extractable protein content is dependent upon both the temperature and time of drying of wet-gel deposit. Wet-gel leaching of film alone is not adequate to reduce the extractable protein content of films to low levels. Combination of wet-gel leaching, post-leaching, a dip in corn starch slurry, followed by drying at a low temperature of 70 degree C reduces the extractable protein content of films to very low levels

  15. Physical vapor deposition of Er.sup.3+./sup.: Yb.sub.3./sub.Al.sub.5./sub.O.sub.12./sub. thin films from sol-gel derived targets

    Czech Academy of Sciences Publication Activity Database

    Hlásek, T.; Rubešová, K.; Jakeš, V.; Nováček, M.; Oswald, Jiří; Fitl, P.; Siegel, J.; Macháč, P.

    2016-01-01

    Roč. 60, č. 4 (2016), s. 285-290 ISSN 0862-5468 Institutional support: RVO:68378271 Keywords : PLD * electron beam deposition * thin film * ytterbium-aluminium garnet * erbium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.439, year: 2016

  16. 3D MR gel dosimetry with lung equivalent gel; 3D MR-Gel-Dosimetrie mit lungenaequivalentem Gel

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, J.; Solleder, M.; Schiessl, I.; Bogner, L.; Herbst, M. [Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Regensburg Univ. (Germany)

    1998-12-31

    The MR gel dosimetry is used to verify complex 3D treatment plans. Till now this method served only for dose evaluation in homogeneous phantoms. On the way to build a heterogeneous anthropomorphic gel phantom, a lung equivalent gel with the density 0.4 g/cm{sup 3} was developed. First experiments show a 1.55 times higher dose reponse in the low density gel (LD gel). The comparison of a dose distribution in a gel/LD gel/gel slab phantom with Monte Carlo calculations shows good agreement within 5%. More over the accuray of the measuring device magnetic resonance imager was studied in respect to the now exclusive digital image processing with the software MRD (MR dosimetry). Because of the dimensions of the Fricke gel phantom an artefact correction, based on the data from the unirradiated phantom proved to be essential. (orig.) [Deutsch] Die MR-Gel-Dosimetrie zur Verifikation komplexer 3D-Bestrahlungsplaene wurde bislang ausschliesslich in homogenen Phantomen durchgefuehrt. Auf dem Wege zum Bau eines inhomogenen Humanoid-Gel-Phantoms wurde ein lungenaequivalentes Gel mit der Dichte 0,4 g/cm{sup 3} entwickelt. Erste Messungen zeigen ein um den Faktor 1,55 hoeheres Ansprechvermoegen in dem low-density-Gel (LD-Gel). Der Vergleich einer gemessen Dosisverteilung in einem Gel/LD-Gel/Gel Schichtphantom als einfaches Thoraxmodell mit Monte-Carlo-Rechnungen zeigt eine gute Uebereinstimmung innerhalb 5%. Ausserdem wurden Untersuchungen zur Messgenauigkeit des Kernspintomographen im Rahmen der nun ausschliesslich digitalen Auswertung mit Hilfe des Programms MRD (MR-Dosimetrie) durchgefuehrt. Es zeigt sich, dass eine Artefaktkorrektur auf der Basis einer Messung des unbestrahlten Phantoms bei grossen Fricke-Gel-Phantomen notwendig ist. (orig.)

  17. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    Bull. Mater. Sci., Vol. 29, No. 7, December 2006, pp. 673–678. © Indian Academy of Sciences. 673. Investigation on poly (vinylidene fluoride) based gel polymer electrolytes ... (Alamgir and Abraham 1993; Sukeshini et al 1996; Ra- jendran and Uma ... Yang et al 1996; Ramesh and Arof 2001) and such elec- trolytes exhibit ...

  18. gel template method

    Indian Academy of Sciences (India)

    TiO2 nanotubes have been synthesized by sol–gel template method using alumina membrane. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, UV absorption spectrum and X-ray diffraction techniques have been used to investigate the structure, morphology and optical ...

  19. Electrophoretic deposition of sol-gel-derived ceramic coatings

    International Nuclear Information System (INIS)

    Zhang, Y.; Crooks, R.M.

    1992-01-01

    In this paper the physical, optical, and chemical characteristics of electrophoretically and dip-coated sol-gel ceramic films are compared. The results indicate that electrophoresis may allow a higher level of control over the chemistry and structure of ceramic coatings than dip-coating techniques. For example, controlled-thickness sol-gel coatings can be prepared by adjusting the deposition time or voltage. Additionally, electrophoretic coatings can be prepared in a four-component alumino-borosilicate sol display interesting optical characteristics. For example, the ellipsometrically-measured refractive indices of electrophoretic coatings are higher than the refractive indices of dip-coated films cast from identical sols, and they are also higher than any of the individual sol components. This result suggests that there are physical and/or chemical differences between films prepared by dip-coating and electrophoresis

  20. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation

    Directory of Open Access Journals (Sweden)

    Gyati Shilakari Asthana

    2016-01-01

    Full Text Available The present study aimed to investigate the delivery potential of Etodolac (ETD containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1 ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%. TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2 displayed high percentage of drug release after 24 h (94.91 at (1 : 1 ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug.

  1. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation.

    Science.gov (United States)

    Shilakari Asthana, Gyati; Asthana, Abhay; Singh, Davinder; Sharma, Parveen Kumar

    2016-01-01

    The present study aimed to investigate the delivery potential of Etodolac (ETD) containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP) was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1) ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%). TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2) displayed high percentage of drug release after 24 h (94.91) at (1 : 1) ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug.

  2. Development of strippable gel for surface decontamination applications

    International Nuclear Information System (INIS)

    Banerjee, D.; Sandhya, U.; Khot, S.A.; Srinivas, C.

    2015-07-01

    Strippable gels are an attractive option for decontamination of surfaces particularly when materials are to be reused after decontamination. The process in general results in good decontamination performance with minimal secondary waste generation. This paper reports on development of strippable gel formulation using polyvinyl alcohol as the gel former. Peeling behavior of the gel film improved when glycerol was used as plasticizer. Incorporation of decontaminating agents is essential for the gel to be effective, so a number of decontaminating agents were screened based on their miscibility with the gel, smooth peeling, and good decontamination performance. Based on this study, a strippable gel, ‘INDIGEL’ was formulated as a potential candidate for surface decontamination applications. Extensive trials on evaluation of decontamination performance of Indigel were done on simulated surfaces like stainless steel tray, stainless steel fume hood, PVC floor, granite and ceramic table tops. Results show that Indigel is highly effective for decontamination of surfaces contaminated with all types of radionuclides. Simplicity of its use coupled with good decontamination ability will find application in nuclear and other chemical industries. (author)

  3. Western Blot of Stained Proteins from Dried Polyacrylamide Gels

    Science.gov (United States)

    Gruber, Claudia; Stan-Lotter, Helga

    1996-01-01

    Western blotting of proteins is customarily performed following their separation on polyacrylamide gels, either prior to staining (1) or, as recently reported, following staining (2). We describe here Western blotting with stained gels, which had been dried and some of which had been stored for years. This procedure permits immunological analysis of proteins, to which antisera may have become available only later, or where the application of newly developed sensitive detection methods is desired. Once rehydration of the gels is achieved, proteins can be-transferred to blotting membranes by any appropriate protocol. Proteins stained with Coomassie Blue have to be detected with a non-chromogenic method, such as the film-based enhanced chemiluminescence (ECL)2) procedure (3). Silver stained proteins, which transfer in the colorless form, may be visualized by any detection method, although, because of the usually very low amounts of proteins, detection by ECL is preferable. Blotting of stained proteins from rehydrated gels is as rapid and as quantitative as from freshly prepared gels, in contrast to blotting from wet stained gels, which requires extensive washing and results in low transfer efficiency (2). Together with a photographic record of the gel pattern, unambiguous identification of immunoreactive proteins from complex mixtures is possible. Some further applications of this work are discussed.

  4. Shrinking properties of electron irradiated polyethylene film

    International Nuclear Information System (INIS)

    Pino, Eddy Segura; Lima, Wanderley de; Silva, Leonardo G. de Andrade; Rzyski, Barbara Maria

    1997-01-01

    This paper describes the evaluation of shrinkable properties of a commercial polyethylene film irradiated with accelerated electrons. The shrinking ratio, elongation ratio and the shrinking effect value were used to compare the shrinkable performance of the film at different irradiation absorbed doses. The cross-linking density evolution was determined by gel fraction determination. (author)

  5. Dynamic partitioning of nanoparticulate metal species between gel layers and aqueous media

    NARCIS (Netherlands)

    Veeken, van der P.L.R.

    2010-01-01

    This thesis deals with several aspects of the use of Diffusive Gradient in Thin film (DGT) and Diffusive Equilibriation in Thin film (DET) in dynamic metal speciation analysis. It has a clear focus on the properties of the diffusive gel layer, and their possible impact on metal speciation

  6. Structural modification and band gap engineering of sol–gel dip

    Indian Academy of Sciences (India)

    In the present study, we investigated the effect of vacuum annealing on the structural and optical properties of sol–gel dip-coated thin films of Zn 0.75 Mg 0.25 O alloy. XRD studies revealed that all these films werepolycrystalline with hexagonal wurtzite structure and there was no trace of additional phases other than ZnO.

  7. Structural modification and band gap engineering of sol–gel dip ...

    Indian Academy of Sciences (India)

    In the present study, we investigated the effect of vacuum annealing on the structural and optical properties of sol–gel dip-coated thin films of Zn 0.75 Mg 0.25 O alloy. XRD studies revealed that all these films werepolycrystalline with hexagonal wurtzite structure and there was no trace of additional phases other than ZnO.

  8. Neutron detector based on lithiated sol-gel glass

    CERN Document Server

    Wallace, S; Miller, L F; Dai, S

    2002-01-01

    A neutron detector technology is demonstrated based on sup 6 Li/ sup 1 sup 0 B doped sol-gel glass. The detector is a sol-gel glass film coated silicon surface barrier detector (SBD). The ionized charged particles from (n, alpha) reactions in the sol-gel film enter the SBD and are counted. Data showing that gamma-ray pulse amplitudes interfere with identifying charged particles that exit the film layer with energies below the gamma-ray energy is presented. Experiments were performed showing the effect of sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co gamma rays on the SBD detector. The reaction product energies of the triton and alpha particles from sup 6 Li are significantly greater than the energies of the Compton electrons from high-energy gamma rays, allowing the measurement of neutrons in a high gamma background. The sol-gel radiation detection technology may be applicable to the characterization of transuranic waste, spent nuclear fuel and to the monitoring of stored plutonium.

  9. Nanostructured sol-gel coatings doped with cerium nitrate as pre-treatments for AA2024-T3

    International Nuclear Information System (INIS)

    Zheludkevich, M.L.; Serra, R.; Montemor, M.F.; Yasakau, K.A.; Salvado, I.M. Miranda; Ferreira, M.G.S.

    2005-01-01

    Nanostructured hybrid sol-gel coatings doped with cerium ions were investigated in the present work as pre-treatments for the AA2024-T3 alloy. The sol-gel films have been synthesized from tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) precursors. Additionally the hybrid sol was doped with zirconia nanoparticles prepared from hydrolyzed tetra-n-propoxyzirconium (TPOZ). Cerium nitrate, as corrosion inhibitor, was added into the hybrid matrix or into the oxide nanoparticles. The chemical composition and the structure of the hybrid sol-gel films were studied by XPS (X-ray photoelectron spectroscopy) and AFM (atomic force microscopy), respectively. The evolution of the corrosion protection properties of the sol-gel films was studied by EIS (electrochemical impedance spectroscopy), which can provide quantitative information on the role of the different pre-treatments. Different equivalent circuits, for different stages of the corrosion processes, were used in order to model the coating degradation. The models were supported by SEM (scanning electron microscopy) measurements. The results show that the sol-gel films containing zirconia nanoparticles present improved barrier properties. Doping the hybrid nanostructured sol-gel coatings with cerium nitrate leads to additional improvement of the corrosion protection. The zirconia particles present in the sol-gel matrix seem to act as nanoreservoirs providing a prolonged release of cerium ions. The nanostructured sol-gel films doped with cerium nitrate can be proposed as a potential candidate for substitution of the chromate pre-treatments for AA2024-T3

  10. Biopolymer gels containing fructooligosaccharides.

    Science.gov (United States)

    Silva, Karen Cristina Guedes; Sato, Ana Carla Kawazoe

    2017-11-01

    The influence of the addition of fructooligosaccharide (FOS) in an external gelated alginate/gelatin biopolymer matrix, was evaluated in order to produce biopolymeric structures with functional effects. Solutions were characterized regarding their rheological properties, macrogels regarding their microstructure and mechanical properties and microgels were characterized in relation to their particle size distribution and morphology. Close relationship was found between the microstructure, rheological and mechanical properties of the biopolymeric systems. An increased viscosity and accentuated elastic and pseudoplastic behavior were associated to denser microstructures. The FOS addition caused changes in the evaluated properties, resulting in more cohesive structures, with smaller pores and higher viscosity, compared to alginate-gelatin gels. The addition of 3% FOS to biopolymeric system provided an optimal condition, allowing the formation of stronger gels, with smaller pores and beads with smaller sizes, indicating the potential use of these functional systems as texture modifiers or encapsulation systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Sol-gel bonding of silicon wafers

    International Nuclear Information System (INIS)

    Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

    2005-01-01

    Low temperature bonding of silicon wafers was achieved using sol-gel technology. The initial sol-gel chemistry of the coating solution was found to influence the mechanical properties of the resulting bonds. More precisely, the influence of parameters such as the alkoxide concentration, water-to-alkoxide molar ratio, pH, and solution aging on the final bond morphologies and interfacial fracture energy was studied. The thickness and density of the sol-gel coating were characterised using ellipsometry. The corresponding bonded specimens were investigated using attenuated total reflectance Fourier transformed infrared spectroscopy to monitor their chemical composition, infrared imaging to control bond integrity, and cross-sectional transmission electron microscopy to study their microstructure. Their interfacial fracture energy was measured using microindentation. An optimum water-to-alkoxide molar ratio of 10 and hydrolysis water at pH = 2 were found. Such conditions led to relatively dense films (> 90%), resulting in bonds with a fracture energy of 3.5 J/m 2 , significantly higher than those obtained using classical hydrophilic bonding (typically 1.5-2.5 J/m 2 ). Ageing of the coating solution was found to decrease the bond strength

  12. Chiromagnetic nanoparticles and gels

    Science.gov (United States)

    Yeom, Jihyeon; Santos, Uallisson S.; Chekini, Mahshid; Cha, Minjeong; de Moura, André F.; Kotov, Nicholas A.

    2018-01-01

    Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic Co3O4 nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size. Transparency of the nanoparticle gels to circularly polarized light beams in the ultraviolet range was reversibly modulated by magnetic fields. These phenomena were also observed for other nanoscale metal oxides with lattice distortions from imprinted amino acids and other chiral ligands. The large family of chiral ceramic nanostructures and gels can be pivotal for new technologies and knowledge at the nexus of chirality and magnetism.

  13. Polyacrylamide gel electrophoresis of RNA.

    Science.gov (United States)

    Rio, Donald C; Ares, Manuel; Hannon, Gregory J; Nilsen, Timothy W

    2010-06-01

    Perhaps the most important and certainly the most often used technique in RNA analysis is gel electrophoresis. This technique is generally applicable for RNA detection, quantification, purification by size, and quality assessment. Because RNAs are negatively charged, they migrate toward the anode in the presence of electric current. The gel acts as a sieve to selectively impede the migration of the RNA in proportion to its mass, given that its mass is generally proportional to its charge. Because mass is approximately related to chain length, the length of an RNA is more generally determined by its migration. In addition, topology (i.e., circularity) can affect migration, making RNAs appear longer on the gel than they actually are. Gels are used in a wide variety of techniques, including Northern blotting, primer extension, footprinting, and analyzing processing reactions. They are invaluable as preparative and fractionating tools. There are two common types of gel: polyacrylamide and agarose. For most applications, denaturing acrylamide gels are most appropriate. These gels are extremely versatile and can resolve RNAs from ~600 to RNA-protein complexes, native gels are appropriate. The only disadvantage to acrylamide gels is that they are not suitable for analyzing large RNAs (> or =600 nt); for such applications, agarose gels are preferred. This protocol describes how to prepare, load, and run polyacrylamide gels for RNA analysis.

  14. Effect of concentrations of plasticizers on the sol-gel properties developed from alkoxides precursors

    Energy Technology Data Exchange (ETDEWEB)

    Kunst, Sandra Raquel; Longhi, Marielen; Zini, Lucas Pandolphi [Universidade de Caxias do Sul (CCET/UCS), Caxias do Sul, RS (Brazil). Centro de Ciências Exatas e Tecnologia; Beltrami, Lilian Vanessa Rossa; Boniatti, Rosiana; Cardoso, Henrique Ribeiro Piaggio; Vega, Maria Rita Ortega; Malfatti, Célia de Fraga, E-mail: lvrossa@yahoo.com.br [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Laboratorio de Pesquisa em Corrosão

    2017-07-01

    Coatings developed through sol-gel method is presented as an interesting replacement to chromium coating. Sol-gel method present advantages as high purity and excellent distribution of the components. The objective of this work is to synthesize and characterize a film obtained by sol-gel route. The film was prepared with 3-(trimethoxysilylpropyl) methacrylate (TMSPMA), tetraethoxysilane (TEOS) and cerium nitrate, using water and ethanol as solvents. Polyethyleneglycol (PEG) plasticizer was added at four different concentrations. The sol was characterized by techniques of viscosity, thermogravimetric analysis (TGA), X-ray diffraction (XRD) nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). The results showed that tetrafunctional alkoxides condensation was retarded by the plasticizer, forming a compact film. The film with 20 g.L-1 of PEG showed the best electrochemical behavior. (author)

  15. Bi-Sr-Co-O thermoelectrics prepared by sol-gel methods with modified gel decomposition

    Czech Academy of Sciences Publication Activity Database

    Rubešová, K.; Hlásek, T.; Jakeš, V.; Sedmidubský, D.; Hejtmánek, Jiří

    2012-01-01

    Roč. 30, č. 1 (2012), 1-5 ISSN 1757-8981. [Fall Meeting of the European-Materials-Research-Society (E-MRS)/Symposium K - Solution-Derived Electronic-Oxide Films, Nanostructures and Patterning, from Materials to Devices. Warsaw, 19.09.2011-23.09.2011] R&D Projects: GA ČR GA203/09/1036 Institutional research plan: CEZ:AV0Z10100521 Keywords : BiSrCoO * thermoelectrics * sol–gel Subject RIV: BM - Solid Matter Physics ; Magnetism

  16. Improving the scratch resistance of sol-gel metal oxide coatings cured at 250 C through use of thermogenerated amines

    NARCIS (Netherlands)

    Langanke, J.; Arfsten, N.; Buskens, P.; Habets, R.; Klankermayer, J.; Leitner, W.

    2013-01-01

    Scratch resistant sol-gel metal oxide coatings typically require a thermal post-treatment step (curing process) at temperatures between 400 and 700 C. In this report, we demonstrate that the in situ generation of amines within sol-gel films facilitates the preparation of scratch resistant metal

  17. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  18. Thoria sol-gel processes

    International Nuclear Information System (INIS)

    Matthews, R.B.

    1978-10-01

    Alternate fuel fabrication techniques are being developed at WNRE as part of the thorium fuel cycle program. The sol-gel techniques are attractive and this report assembles and summarizes information relating to thoria sol-gel fuels. Some background information on the behaviour and advantages of sol-gel fuel forms is presented, followed by a review of relevant colloid chemistry and an explanation of the fundamental steps of sol-gel processes. Finally, several variants to the basic process are reviewed and evaluated. (author)

  19. Radiotherapy gel dosimetry: a review

    International Nuclear Information System (INIS)

    Baldock, C.

    2003-01-01

    Radiation therapy or radiotherapy is a common form of cancer treatment. Recent advances in radiotherapy such as intensity modulated radiation therapy indicate that treatment outcomes may be improved. The principle limitation of these more advanced techniques of radiation therapy is the ability to quantify the absorbed radiation dose to the tumour which is related to the 3- dimensional geometry of the tumour. The main advances in 3-dimensional radiation dosimetry are the development of radiation sensitive polymer gel dosimeters. The use of radiation sensitive gels for radiation dosimetry in cancer therapy was first suggested in the 1950s. It was subsequently shown in 1984 that radiation induced changes in nuclear magnetic resonance relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. Due to diffusion-related limitations in the use of Fricke gels, alternative polymer gel dosimeters were subsequently suggested in 1992. Since then, both magnetic resonance and optical imaging techniques have been used to evaluate polymer gel dosimeters to produce three-dimensional radiation dose distributions. More recently the uses of x-ray computer tomography and vibrational spectroscopy have also been demonstrated as valuable techniques in the evaluation of these dosimetry gels. Although not yet used routinely clinically, applications of these radiologically soft-tissue equivalent gel dosimeters have been shown to have great potential in the evaluation of complex radiation dose distributions. A review of 3-dimensional radiotherapy gel dosimetry is presented

  20. Preparation of high dielectric constant thin films of CaCu3 Ti4 by sol ...

    Indian Academy of Sciences (India)

    WINTEC

    Preparation of sol–gel derived CaCu3Ti4O12 (CCTO) thin films using two different sols and their characterization including their ... Sol–gel preparation; thin film; electrical properties. 1. Introduction. High dielectric constant .... The dots on the plots are the experi- mental points and the lines show their fit to semicircles.

  1. 1T1R Nonvolatile Memory with Al/TiO2/Au and Sol-Gel-Processed Insulator for Barium Zirconate Nickelate Gate in Pentacene Thin Film Transistor

    Directory of Open Access Journals (Sweden)

    Ke-Jing Lee

    2017-12-01

    Full Text Available A one-transistor and one-resistor (1T1R architecture with a resistive random access memory (RRAM cell connected to an organic thin-film transistor (OTFT device is successfully demonstrated to avoid the cross-talk issues of only one RRAM cell. The OTFT device, which uses barium zirconate nickelate (BZN as a dielectric layer, exhibits favorable electrical properties, such as a high field-effect mobility of 2.5 cm2/Vs, low threshold voltage of −2.8 V, and low leakage current of 10−12 A, for a driver in the 1T1R operation scheme. The 1T1R architecture with a TiO2-based RRAM cell connected with a BZN OTFT device indicates a low operation current (10 μA and reliable data retention (over ten years. This favorable performance of the 1T1R device can be attributed to the additional barrier heights introduced by using Ni (II acetylacetone as a substitute for acetylacetone, and the relatively low leakage current of a BZN dielectric layer. The proposed 1T1R device with low leakage current OTFT and excellent uniform resistance distribution of RRAM exhibits a good potential for use in practical low-power electronic applications.

  2. Film/NotFilm

    OpenAIRE

    Willems, Gertjan

    2016-01-01

    Although Samuel Beckett (1906-1989) showed a genuine interest in audio-visual media in his fascinating and innovative radio plays and television works, and in 1936 even wrote a letter to Sergei Eisenstein to be accepted to the famous Soviet film school VGIK, the 22-minute Film (1965) was his only venture into cinema. Beckett conceived the film, wrote the screenplay, supervised the production and, as one of the film’s crew members recalled and as the director Alan Schneider himself acknowledge...

  3. Rheology and structure of milk protein gels

    NARCIS (Netherlands)

    Vliet, van T.; Lakemond, C.M.M.; Visschers, R.W.

    2004-01-01

    Recent studies on gel formation and rheology of milk gels are reviewed. A distinction is made between gels formed by aggregated casein, gels of `pure` whey proteins and gels in which both casein and whey proteins contribute to their properties. For casein' whey protein mixtures, it has been shown

  4. Gel placement in porous media

    NARCIS (Netherlands)

    F.J. Vermolen; J. Bruining; C.J. van Duijn (Hans)

    1999-01-01

    textabstractIn this paper we analyse advective transport of polymers, crosslinkers and gel, taking into account non-equilibrium gelation, gel adsorption and crosslinker precipitation. In absence of diffusion/dispersion the resulting model consists of hyperbolic transport-reaction equations. These

  5. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  6. Laser-induced transfer of gel microdroplets for cell printing

    Science.gov (United States)

    Yusupov, V. I.; Zhigar'kov, V. S.; Churbanova, E. S.; Chutko, E. A.; Evlashin, S. A.; Gorlenko, M. V.; Cheptsov, V. S.; Minaev, N. V.; Bagratashvili, V. N.

    2017-12-01

    We study thermal and transport processes involved in the transfer of gel microdroplets under the conditions of laser cell microprinting. The specific features of the interaction of pulsed laser radiation ( λ = 1.064 µm, pulse duration 4 - 200 ns, energy 2 µJ - 1 mJ) with the absorbing gold film deposited on the glass donor substrate are determined. The investigation of the dynamics of transport processes by means of fast optical video recording and optoacoustic methods makes it possible to determine the characteristics of the produced gel jets as functions of the laser operation regimes. The hydrodynamic process of interaction between the laser radiation and the gold coating with the hydrogel layer on it is considered and the temperature in the region of the laser pulse action is estimated. It is shown that in the mechanism of laser-induced transfer a significant role is played by the processes of explosive boiling of water (in gel) and gold. The amount of gold nanoparticles arriving at the acceptor plate in the process of the laser transfer is determined. For the laser pulse duration 8 ns and small energies (less than 10 µJ), the fraction of gold nanoparticles in the gel microdroplets is negligibly small, and their quantity linearly grows with increasing pulse energy. The performed studies offer a base for optimising the processes of laser transfer of gel microdroplets in the rapidly developing technologies of cell microprinting.

  7. Nanostructured thin films and coatings functional properties

    CERN Document Server

    Zhang, Sam

    2010-01-01

    The second volume in ""The Handbook of Nanostructured Thin Films and Coatings"" set, this book focuses on functional properties, including optical, electronic, and electrical properties, as well as related devices and applications. It explores the large-scale fabrication of functional thin films with nanoarchitecture via chemical routes, the fabrication and characterization of SiC nanostructured/nanocomposite films, and low-dimensional nanocomposite fabrication and applications. The book also presents the properties of sol-gel-derived nanostructured thin films as well as silicon nanocrystals e

  8. One-step sol-gel imprint lithography for guided-mode resonance structures.

    Science.gov (United States)

    Huang, Yin; Liu, Longju; Johnson, Michael; C Hillier, Andrew; Lu, Meng

    2016-03-04

    Guided-mode resonance (GMR) structures consisting of sub-wavelength periodic gratings are capable of producing narrow-linewidth optical resonances. This paper describes a sol-gel-based imprint lithography method for the fabrication of submicron 1D and 2D GMR structures. This method utilizes a patterned polydimethylsiloxane (PDMS) mold to fabricate the grating coupler and waveguide for a GMR device using a sol-gel thin film in a single step. An organic-inorganic hybrid sol-gel film was selected as the imprint material because of its relatively high refractive index. The optical responses of several sol-gel GMR devices were characterized, and the experimental results were in good agreement with the results of electromagnetic simulations. The influence of processing parameters was investigated in order to determine how finely the spectral response and resonant wavelength of the GMR devices could be tuned. As an example potential application, refractometric sensing experiments were performed using a 1D sol-gel device. The results demonstrated a refractive index sensitivity of 50 nm/refractive index unit. This one-step fabrication process offers a simple, rapid, and low-cost means of fabricating GMR structures. We anticipate that this method can be valuable in the development of various GMR-based devices as it can readily enable the fabrication of complex shapes and allow the doping of optically active materials into sol-gel thin film.

  9. Chemical Gel for Surface Decontamination

    International Nuclear Information System (INIS)

    Jung, Chong Hun; Moon, J. K.; Won, H. J.; Lee, K. W.; Kim, C. K.

    2010-01-01

    Many chemical decontamination processes operate by immersing components in aggressive chemical solutions. In these applications chemical decontamination technique produce large amounts of radioactive liquid waste. Therefore it is necessary to develop processes using chemical gels instead of chemical solutions, to avoid the well-known disadvantages of chemical decontamination techniques while retaining their high efficiency. Chemical gels decontamination process consists of applying the gel by spraying it onto the surface of large area components (floors, walls, etc) to be decontaminated. The gel adheres to any vertical or complex surface due to their thixotropic properties and operates by dissolving the radioactive deposit, along with a thin layer of the gel support, so that the radioactivity trapped at the surface can be removed. Important aspects of the gels are that small quantities can be used and they show thixitropic properties : liquid during spraying, and solid when stationary, allowing for strong adherence to surfaces. This work investigates the decontamination behaviors of organic-based chemical gel for SS 304 metallic surfaces contaminated with radioactive materials

  10. Denaturing gradient gel electrophoresis

    International Nuclear Information System (INIS)

    Kocherginskaya, S.A.; Cann, I.K.O.; Mackie, R.I.

    2005-01-01

    It is worthwhile considering that only some 30 species make up the bulk of the bacterial population in human faeces at any one time based on the classical cultivation-based approach. The situation in the rumen is similar. Thus, it is practical to focus on specific groups of interest within the complex community. These may be the predominant or the most active species, specific physiological groups or readily identifiable (genetic) clusters of phylogenetically related organisms. Several 16S rDNA fingerprinting techniques can be invaluable for selecting and monitoring sequences or phylogenetic groups of interest and are described below. Over the past few decades, considerable attention was focussed on the identification of pure cultures of microbes on the basis of genetic polymorphisms of DNA encoding rRNA such as ribotyping, amplified fragment length polymorphism and randomly amplified polymorphic DNA. However, many of these methods require prior cultivation and are less suitable for use in analysis of complex mixed populations although important in describing cultivated microbial diversity in molecular terms. Much less attention was given to molecular characterization of complex communities. In particular, research into diversity and community structure over time has been revolutionized by the advent of molecular fingerprinting techniques for complex communities. Denaturing or temperature gradient gel electrophoresis (DGGE/TGGE) methods have been successfully applied to the analysis of human, pig, cattle, dog and rodent intestinal populations

  11. Study of silica sol-gel materials for sensor development

    Science.gov (United States)

    Lei, Qiong

    Silica sol-gel is a transparent, highly porous silicon oxide glass made at room temperature by sol-gel process. The name of silica sol-gel comes from the observable physical phase transition from liquid sol to solid gel during its preparation. Silica sol-gel is chemically inert, thermally stable, and photostable, it can be fabricated into different desired shapes during or after gelation, and its porous structure allows encapsulation of guest molecules either before or after gelation while still retaining their functions and sensitivities to surrounding environments. All those distinctive features make silica sol-gel ideal for sensor development. Study of guest-host interactions in silica sol-gel is important for silica-based sensor development, because it helps to tailor local environments inside sol-gel matrix so that higher guest loading, longer shelf-life, higher sensitivity and faster response of silica gel based sensors could be achieved. We focused on pore surface modification of two different types of silica sol-gel by post-grafting method, and construction of stable silica hydrogel-like thin films for sensor development. By monitoring the mobility and photostability of rhodamine 6G (R6G) molecules in silica alcogel thin films through single molecule spectroscopy (SMS), the guest-host interactions altered by post-synthesis grafting were examined. While physical confinement remains the major factor that controls mobility in modified alcogels, both R6G mobility and photostability register discernable changes after surface charges are respectively reversed and neutralized by aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTES) grafting. The change in R6G photostability was found to be more sensitive to surface grafting than that of mobility. In addition, silica film modification by 0.4% APTS is as efficient as that by pure MTES in lowering R6G photostability, which suggests that surface charge reversal is more effective than charge neutralization

  12. Fluoride Rinses, Gels and Foams

    DEFF Research Database (Denmark)

    Twetman, Svante; Keller, Mette K

    2016-01-01

    AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

  13. Injectable gels for tissue engineering.

    Science.gov (United States)

    Gutowska, A; Jeong, B; Jasionowski, M

    2001-08-01

    Recently, tissue engineering approaches using injectable, in situ gel forming systems have been reported. In this review, the gelation processes and several injectable systems that exhibit in situ gel formation at physiological conditions are discussed. Applications of selected injectable systems (alginate, chitosan, hyaluronan, polyethylene oxide/polypropylene oxide) in tissue engineering are also described. Injectable polymer formulation can gel in vivo in response to temperature change (thermal gelation), pH change, ionic cross-linking, or solvent exchange. Kinetics of gelation is directly affected by its mechanism. Injectable formulations offer specific advantages over preformed scaffolds such as: possibility of a minimally invasive implantation, an ability to fill a desired shape, and easy incorporation of various therapeutic agents. Several factors need to be considered before an injectable gel can be selected as a candidate for tissue engineering applications. Apart from tissue-specific cell-matrix interactions, the following gel properties need to be considered: gelation kinetics, matrix resorption rate, possible toxicity of degradation products and their elimination routes, and finally possible interference of the gel matrix with histogenesis. Copyright 2001 Wiley-Liss, Inc.

  14. Manufacturing of patterned ZnO films with application for ...

    Indian Academy of Sciences (India)

    Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol–gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with hexagonal crystal structure, are characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction.

  15. Manufacturing of patterned ZnO films with application for ...

    Indian Academy of Sciences (India)

    Administrator

    Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria. MS received 30 December 2008; revised 11 July 2009. Abstract. Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol–gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with ...

  16. High coercivity in nanostructured Co-ferrite thin films

    Indian Academy of Sciences (India)

    with a thickness of ~ 100 nm deposited using PLD with a substrate temperature at 550°C. The Co-ferrite films prepared by PLD at over ... the high coercivity is related with a large residual strain, which may induce an additional magnetic anisotropy .... of the spinel phase for both sol–gel and sputtering grown films starts at ...

  17. Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

    Science.gov (United States)

    Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

    2004-01-01

    An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

  18. Surface Properties of Photocatalytic Nano-Crystalline Titania Films and Reactor for Photocatalytic Degradation of Chloroform

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jensen, Henrik

    2006-01-01

    In this work two immobilizations techniques of TiO2 onto glass were investigated; deposition of previously made titania powder (PMTP) and a sol-gel method. The titania powder used in this work was Degussa P25, Hombikat UV100 and a powder prepared in our laboratory SC134. The prepared TiO2 films...... were characterized using XRD, XPS, AFM, UV-Vis spectroscopy and the photocatalytic activity was assessed using stearic acid as a model compound. Investigation of the prepared films showed that the films prepared from Degussa P25 was the most active, followed by the Hombikat UV100 film, Sol-gel film...

  19. Determination of Insulator-to-Semiconductor Transition in Sol-Gel Oxide Semiconductors Using Derivative Spectroscopy

    Directory of Open Access Journals (Sweden)

    Woobin Lee

    2015-12-01

    Full Text Available We report a derivative spectroscopic method for determining insulator-to-semiconductor transition during sol-gel metal-oxide semiconductor formation. When an as-spun sol-gel precursor film is photochemically activated and changes to semiconducting state, the light absorption characteristics of the metal-oxide film is considerable changed particularly in the ultraviolet region. As a result, a peak is generated in the first-order derivatives of light absorption (A′ vs. wavelength (λ plots, and by tracing the peak center shift and peak intensity, transition from insulating-to-semiconducting state of the film can be monitored. The peak generation and peak center shift are described based on photon-energy-dependent absorption coefficient of metal-oxide films. We discuss detailed analysis method for metal-oxide semiconductor films and its application in thin-film transistor fabrication. We believe this derivative spectroscopy based determination can be beneficial for a non-destructive and a rapid monitoring of the insulator-to-semiconductor transition in sol-gel oxide semiconductor formation.

  20. Multilayered ordered mesoporous platinum/titania composite films: does the photocatalytic activity benefit from the film thickness?

    Czech Academy of Sciences Publication Activity Database

    Ismail, A. A.; Bahnemann, D.; Rathouský, Jiří; Yarovyi, V.; Wark, M.

    2011-01-01

    Roč. 21, č. 21 (2011), s. 7802-7810 ISSN 0959-9428 Institutional research plan: CEZ:AV0Z40400503 Keywords : titanium dioxide films * TiO2 thin films * sol-gel method Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.968, year: 2011

  1. Bleach gel: a simple agarose gel for analyzing RNA quality.

    Science.gov (United States)

    Aranda, Patrick S; LaJoie, Dollie M; Jorcyk, Cheryl L

    2012-01-01

    RNA-based applications requiring high-quality, non-degraded RNA are a foundational element of many research studies. As such, it is paramount that the integrity of experimental RNA is validated prior to cDNA synthesis or other downstream applications. In the absence of expensive equipment such as microfluidic electrophoretic devices, and as an alternative to the costly and time-consuming standard formaldehyde gel, RNA quality can be quickly analyzed by adding small amounts of commercial bleach to TAE buffer-based agarose gels prior to electrophoresis. In the presence of low concentrations of bleach, the secondary structure of RNA is denatured and potential contaminating RNases are destroyed. Because of this, the 'bleach gel' is a functional approach that addresses the need for an inexpensive and safe way to evaluate RNA integrity and will improve the ability of researchers to rapidly analyze RNA quality. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Screen-printable sol-gel enzyme-containing carbon inks.

    Science.gov (United States)

    Wang, J; Pamidi, P V; Park, D S

    1996-08-01

    Enzymes usually cannot withstand the high-temperature curing associated with the thick-film fabrication process and require a separate immobilization step in connection with the production of single-use biosensors. We report on the development of sol-gel-derived enzyme-containing carbon inks that display compatibility with the screen-printing process. Such coupling of sol-gel and thick-film technologies offers a one-step fabrication of disposable enzyme electrodes, as it obviates the need for thermal curing. The enzyme-containing sol-gel carbon ink, prepared by dispersing the biocatalyst, along with the graphite powder and a binder, within the sol-gel precursors, is cured very rapidly (10 min) at low temperature (4 °C). The influence of the ink preparation conditions is explored, and the sensor performance is evaluated in connection with the incorporation of glucose oxidase or horseradish peroxidase. The resulting strips are stable for at least 3 months. Such sol-gel-derived carbon inks should serve as hosts for other heat-sensitive biomaterials in connection with the microfabrication of various thick-film biosensors.

  3. Structure and amphoteric properties of titanium dioxide gels

    International Nuclear Information System (INIS)

    Kertesz, C.

    1991-01-01

    Mechanisms responsible for the in-solution ion retention by titanium dioxide are studied. Mineral oxide gel formation and structure are described and various titanium dioxide gel synthesis modes are presented. A two-phase model, taking into account the porous nature of the solid and allowing for the application of the mass action law, is adopted. The oxide amphoteric properties are studied with the potentiometric titration technique. Hysteresis loops are imputed to the slowness of the acid-basic neutralization reaction. The main characteristics are determined: isoelectric point, cation and anion retention capacity. Depending on the suspension agitation, the speed limiting factor may be the diffusion in the film or the diffusion in the particle. 60 fig., 128 ref

  4. Effect of Edible Coatings from Aloe vera gel on Citrus sinensis ...

    African Journals Online (AJOL)

    Extension of the shelf life of orange fruits continues to be a challenge in Nigeria. The search for safe, healthy and environmental friendly treatments has led to increased interest in research into edible and biodegradable films and coatings. In this work, the use of Aloe vera gel as a coating to extend the shelf-life of orange ...

  5. A highly reactive photobase catalytic system for sol–gel polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Chemtob, Abraham, E-mail: abraham.chemtob@uha.fr [Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex (France); De Paz-Simon, Héloïse; Dietlin, Céline; Croutxé-Barghorn, Céline; Salmi, Hanène; Allonas, Xavier [Laboratory of Macromolecular Photochemistry and Engineering, University of Haute-Alsace, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex (France); Chany, Anne-Caroline [Laboratory of Organic and Bioorganic Chemistry, University of Haute Alsace, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex (France); Vidal, Loïc; Rigolet, Séverinne [Institute of Mulhouse Material Science, UMR-CNRS 7361, University of Haute-Alsace, 3 rue Alfred Werner 68093, Mulhouse Cedex (France)

    2014-01-01

    In sol–gel polymerization of alkoxysilane precursors, base catalysts are usually employed to introduce textural properties. Herein, we show the feasibility and interest of a photobase-catalyzed sol–gel reaction to afford silicate films. Our inorganic polymerization is solvent-free, single-step and UV activatable with a mixture of α-aminoacetophenone (photobase generator), benzophenone (photosensitizer) and triphenylphosphine (oxygen scavenger). To date, the present tricomponent photolatent system generating N-alkyl morpholine tertiary amines represents one of the most efficient photobase generators reported so far in sol–gel chemistry. A combination of spectroscopic and electron microscopy techniques enabled to investigate the fundamental chemistry underlying alkoxysilane photopolymerization: reaction mechanism, hydrolysis kinetics and siloxane microstructure. Systematic comparison with a photoacid-catalyzed process revealed also the impact of the photocatalyst nature on film texture, morphology and optical properties. - Highlights: • A very efficient UV-driven photobase-catalyzed sol–gel process. • Single-step film formation without transition through a sol. • Comparison of film properties under photoacid and photobase catalysis.

  6. Influence of protecting gel film on oxidation of zirconium alloys

    Czech Academy of Sciences Publication Activity Database

    Frank, H.; Weishauptová, Zuzana; Vrtílková, V.

    2007-01-01

    Roč. 360, č. 3 (2007), s. 282-292 ISSN 0022-3115 R&D Projects: GA ČR GA106/04/0043 Institutional research plan: CEZ:AV0Z30460519 Keywords : fuel cladding * corrosion * Zirconium oxide Subject RIV: JF - Nuclear Energetics Impact factor: 1.643, year: 2007

  7. Polyacrylamide temperature gradient gel electrophoresis.

    Science.gov (United States)

    Viglasky, Viktor

    2013-01-01

    Temperature Gradient Gel Electrophoresis (TGGE) is a form of electrophoresis in which temperature gradient is used to denature molecules as they move through either acrylamide or agarose gel. TGGE can be applied to analyze DNA, RNA, protein-DNA complexes, and, less commonly, proteins. Separation of double-stranded DNA molecules during TGGE relies on temperature-dependent melting of the DNA duplex into two single-stranded DNA molecules. Therefore, the mobility of DNA reflects not only the size of the molecule but also its nucleotide composition, thereby allowing separation of DNA molecules of similar size with different sequences. Depending on the relative orientation of electric field and temperature gradient, TGGE can be performed in either a parallel or a perpendicular mode. The former is used to analyze multiple samples in the same gel, whereas the later allows detailed analysis of a single sample. This chapter is focused on analysis of DNA by polyacrylamide TGGE using the perpendicular mode.

  8. Sol-gel derived sorbents

    Science.gov (United States)

    Sigman, Michael E.; Dindal, Amy B.

    2003-11-11

    Described is a method for producing copolymerized sol-gel derived sorbent particles for the production of copolymerized sol-gel derived sorbent material. The method for producing copolymerized sol-gel derived sorbent particles comprises adding a basic solution to an aqueous metal alkoxide mixture for a pH.ltoreq.8 to hydrolyze the metal alkoxides. Then, allowing the mixture to react at room temperature for a precalculated period of time for the mixture to undergo an increased in viscosity to obtain a desired pore size and surface area. The copolymerized mixture is then added to an immiscible, nonpolar solvent that has been heated to a sufficient temperature wherein the copolymerized mixture forms a solid upon the addition. The solid is recovered from the mixture, and is ready for use in an active sampling trap or activated for use in a passive sampling trap.

  9. Nuclear films

    International Nuclear Information System (INIS)

    Malone, Peter.

    1985-01-01

    This booklet is a resource for the study of feature films that highlight the theme of nuclear war. It provides basic credits and brief indication of the theme, treatment, quality and particular notable aspects; and a series of questions raised by the film. Seventy feature films and thirty documentaries are examined

  10. Optical characterization of niobium pentoxide thin films

    International Nuclear Information System (INIS)

    Pawlicka, A.

    1996-01-01

    Thin films of Nb 2 O 5 were obtained by sol-gel method using ultrasonic irradiation and deposited by dip-coating technique. After calcination at temperatures superior than 500 deg C these films (300 nm thick) were characterized by cyclic voltametry and cronoamperometry. The memory measurements, color efficiency, optical density as a function of wave number and applied potential were effectuated to determine their electrochromic properties. The study of electrochromic properties of these films shows that the insertion process of lithium is reversible and changes their coloration from transparent (T=80%) to dark blue (T=20%). (author)

  11. Study of zinc oxide thin film characteristics

    OpenAIRE

    Johari Shazlina; Muhammad Nazalea Yazmin; Zakaria Mohd Rosydi

    2017-01-01

    This paper presents the characterization of ZnO thin films with the thickness of 8nm, 30nm, and 200nm. The thin films were prepared using sol-gel method and has been deposited onto different substrate of silicon wafer, glass and quartz. The thin films were annealed at 400, 500 and 600°C. By using UV-Vis, the optical transmittance measurement were recorded by using a single beam spectrophotometer in the wavelength 250nm to 800nm. However, the transmittance in the visible range is hardly influe...

  12. Controlled deposition of sol–gel sensor material using hemiwicking

    DEFF Research Database (Denmark)

    Mikkelsen, Morten Bo Lindholm; Marie, Rodolphe; Hansen, Jan H

    2011-01-01

    Optical sensors are fabricated by depositing liquid sol–gel sensor material on a polycarbonate surface, which has been decorated with arrays of periodic micropillars. Using the principle of hemiwicking, the liquid material is spread, guided by the surface structures, to homogeneously fill...... the volume between the surface structures and form a liquid film with a thickness determined by the height of the micropillars. After evaporation of solvents, a uniform layer of sensor material resides on the surface. This fabrication method enables easy and reproducible deposits of isolated spots...

  13. Measurement of dynamic wedge angles and beam profiles by means of MRI ferrous sulphate gel dosimetry

    Science.gov (United States)

    Bengtsson, Magnus; Furre, Torbjørn; Rødal, Jan; Skretting, Arne; Olsen, Dag R.

    1996-02-01

    The purpose of this study is to examine the possible value of measuring the dose distribution in dynamic wedge photon beams using ferrous sulphate gel phantoms analysed by MRI. The wedge angles and dose profiles were measured for a field size of and for dynamic wedge angles of , , and using a 15 MV photon beam generated from a Clinac 2100 CD (Varian). The dose profiles obtained from MRI ferrous sulphate gel were in good agreement with the dose measurements performed with a diode detector array. Also, the wedge angles determined from the MRI ferrous sulphate gel agreed well with the values obtained by using film dosimetry and with calculations by use of TMS (treatment planning system) (Helax, Uppsala, Sweden). The study demonstrated that MRI ferrous sulphate gel dosimetry is an adequate tool for measurements of some beam characteristics of dynamic radiation fields.

  14. Optical pH detector based on LTCC and sol-gel technologies

    Science.gov (United States)

    Tadaszak, R. J.; Łukowiak, A.; Golonka, L. J.

    2013-01-01

    This paper presents an investigation on using sol-gel thin film as a material for sensors application in LTCC (Low Temperature Co-fired Ceramics) technology. This material gives the opportunity to make new, low-cost highly integrated optoelectronic devices. Sensors with optical detection are a significant part of these applications. They can be used for quick and safe diagnostics of some parameters. Authors present a pH detector with the optical detection system made of the LTCC material. The main part of the device is a flow channel with the chamber and sol-gel active material. The silica sol-gel with bromocresol green indicator was used. As the absorbance of sol-gel layer changes with the pH value of a measured medium, the transmitted light power was measured. The pH detector was integrated with the electronic components on the LTCC substrate.

  15. Screening effect on nanostructure of charged gel

    DEFF Research Database (Denmark)

    Sugiyama, M; Annaka, M; Hino, M

    2004-01-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions....... The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content. (C) 2004 Elsevier B. V. All rights...

  16. Screening effect on nanostructure of charged gel

    International Nuclear Information System (INIS)

    Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; Vigild, Martin E.; Hara, Kazuhiro

    2004-01-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions. The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content

  17. Screening effect on nanostructure of charged gel

    Science.gov (United States)

    Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; E. Vigild, Martin; Hara, Kazuhiro

    2004-07-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions. The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content.

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

    Science.gov (United States)

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

    2005-08-01

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

  19. Electrical and electrochemical studies on sodium ion-based gel polymer electrolytes

    Science.gov (United States)

    Isa, K. B. Md; Othman, L.; Hambali, D.; Osman, Z.

    2017-09-01

    Gel polymer electrolytes (GPEs) have captured great attention because of their unique properties such as good mechanical stability, high flexibility and high conductivity approachable to that of the liquid electrolytes. In this work, we have prepared sodium ion conducting gel polymer electrolyte (GPE) films consisting of polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) as a polymer host using the solution casting technique. Sodium trifluoromethane- sulfonate (NaCF3SO3) was used as an ionic salt and the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as a plasticizing solvent. Impedance spectroscopy measurements were carried out to determine the ionic conductivity of the GPE films. The sample containing 20 wt.% of NaCF3SO3 salt exhibits the highest room temperature ionic conductivity of 2.50 × 10-3 S cm-1. The conductivity of the GPE films was found to depend on the salt concentration that added to the films. The ionic and cationic transference numbers of GPE films were estimated by DC polarization and the combination of AC and DC polarization method, respectively. The results had shown that both ionic and cationic transference numbers are consistent with the conductivity studies. The electrochemical stability of the GPE films was tested using linear sweep voltammetry (LSV) and the value of working voltage range appears to be high enough to be used as an electrolyte in sodium batteries. The cyclic voltammetry (CV) studies confirmed the sodium ion conduction in the GPE films.

  20. Nonlinear elasticity of alginate gels

    Science.gov (United States)

    Hashemnejad, Seyed Meysam; Kundu, Santanu

    Alginate is a naturally occurring anionic polysaccharide extracted from brown algae. Because of biocompatibility, low toxicity, and simple gelation process, alginate gels are used in biomedical and food applications. Here, we report the rheological behavior of ionically crosslinked alginate gels, which are obtained by in situ gelation of alginates with calcium salts, in between two parallel plates of a rheometer. Strain stiffening behavior was captured using large amplitude oscillatory shear (LAOS) experiments. In addition, negative normal stress was observed for these gels, which has not been reported earlier for any polysaccharide networks. The magnitude of negative normal stress increases with applied strain and can exceed that of the shear stress at large strain. Rheological results fitted with a constitutive model that considers both stretching and bending of chains indicate that nonlinearity is likely related to the stretching of the chains between the crosslink junctions. The results provide an improved understanding of the deformation mechanism of ionically crosslinked alginate gel and the results will be important in developing synthetic extracellular matrix (ECM) from these materials.

  1. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...

  2. Anomalous piezoelectric properties of poly(vinylidene fluoride-trifluoroethylene)/ionic liquid gels

    Science.gov (United States)

    Fukagawa, Miki; Koshiba, Yasuko; Fukushima, Tatsuya; Morimoto, Masahiro; Ishida, Kenji

    2018-04-01

    Piezoelectric gels were prepared from low-volatile ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) gels, and their structural, ferroelectric, and piezoelectric properties were investigated. Poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/IL gels were formed using thermally reversible physical gels. The structural characterization indicated that the P(VDF-TrFE) molecules in the gels predominantly formed a ferroelectric phase (Form I) of P(VDF-TrFE). Polarization switching peaks were clearly observed using a three-layer stacked device structure. The coercive field of the P(VDF-TrFE)/IL gels substantially decreased to 4-9 MV/m, and their remnant polarizations were maintained at 63-71 mC/m2, which is similar to that for typical solid-state P(VDF-TrFE). Finally, the P(VDF-TrFE)/IL gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was ˜300 pm/V at an applied voltage frequency of 4 kHz.

  3. Ion track pores in intelligent films

    International Nuclear Information System (INIS)

    Asano, Masaharu; Yoshida, Masaru; Omichi, Hideki; Nagaoka, Noriyasu; Kubota, Hitoshi; Katakai, Ryoichi; Reber, N.; Spohr, R.

    1996-01-01

    To create an intelligent chemical valve which behaves to biological membranes, we combined the following technologies: (1) creation of intelligent gels based on pendant α-amino acids or their oligomers, (2) preparation of nuclear track films by etching chemically after heavy ion irradiation, especially preparation of cylindrical pores passed through the film, and (3) a combination of (1) and (2). The two factors, REL (Restricted Energy Loss) and radiation sensitivity [(V t /V b )-1] play an important role in formation of such cylindrical track films. In the case of CR-39 film, there were found to be REL>1.6x10 4 MeV cm 2 g -1 and (V t /V b )-1>100, respectively. The cylindrical tracks films with intelligent functions, which consist of a combination of (1) and (2), can be fabricated by two techniques, copolymerization and grafting. (author)

  4. Silicone Gel-Filled Breast Implants

    Science.gov (United States)

    ... and Prosthetics Breast Implants Silicone Gel-Filled Breast Implants Share Tweet Linkedin Pin it More sharing options ... it Email Print Description: Silicone gel-filled breast implants have a silicone outer shell that is filled ...

  5. Yield stress determination of a physical gel

    DEFF Research Database (Denmark)

    Hvidt, Søren

    2013-01-01

    Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresse...... values of these gels depend on test type and measurement time, and no absolute yield stress value can be determined for these physical gels....

  6. Oxti-photo-battery: utilization of new oxygenated titanium polymers for the elaboration of thin photoactive films by sol-gel techniques. Realization of photovoltaic cells exempt from photo sensitizer and development of photo batteries. Concerted actions energy (PE1). Final report. July 2004; Oxti-photobatterie: Utilisation de nouveaux polymeres oxygenes du titane pour l'elaboration de films minces photoactifs par des techniques sol-gel. Realisation de cellules photovoltaiques exemptes de photosensibilisateurs et developpement de photobatteries. Action concertee energie (PE1). Rapport final. Juillet 2004

    Energy Technology Data Exchange (ETDEWEB)

    Brohan, L. [Laboratoire de Chimie des Solides, 44 - Nantes (France); Nunzi, J.M. [Angers Univ., Laboratoire des Proprietes Optiques des Materiaux et Applications, 49 - Angers (France)

    2004-07-01

    This coordinated project aims to elaborate new photovoltaic cells realized from a photosensitive titanium gel, called ''TiDMF''. This inorganic polymer, presents interesting optical properties: it takes a bleu color (by reduction of the Ti{sup 4+} in Ti{sup 3+}), after exposition to the day light. This particularity allows the realization of solar cells exempt from photo sensitizer. (A.L.B.)

  7. Physical Properties of Silicone Gel Breast Implants.

    Science.gov (United States)

    Jewell, Mark L; Bengtson, Bradley P; Smither, Kate; Nuti, Gina; Perry, TracyAnn

    2018-04-28

    Surgical applications using breast implants are individualized operations to fill and shape the breast. Physical properties beyond shape, size, and surface texture are important considerations during implant selection. Compare form stability, gel material properties, and shell thickness of textured shaped, textured round, and smooth round breast implants from 4 manufacturers: Allergan, Mentor, Sientra, and Establishment Labs through bench testing. Using a mandrel height gauge, form stability was measured by retention of dimensions on device movement from a horizontal to vertical supported orientation. Dynamic response of gel material (gel cohesivity, resistance to gel deformation, energy absorption) was measured using a synchronized target laser following application of graded negative pressure. Shell thickness was measured using digital thickness gauge calipers. Form stability, gel material properties, and shell thickness differed across breast implants. Of textured shaped devices, Allergan Natrelle 410 exhibited greater form stability than Mentor MemoryShape and Sientra Shaped implants. Allergan Inspira round implants containing TruForm 3 gel had greater form stability, higher gel cohesivity, greater resistance to gel deformation, and lower energy absorption than those containing TruForm 2 gel and in turn, implants containing TruForm 1 gel. Shell thickness was greater for textured versus smooth devices, and differed across styles. Gel cohesivity, resistance to gel deformation, and energy absorption are directly related to form stability, which in turn determines shape retention. These characteristics provide information to aid surgeons choosing an implant based on surgical application, patient tissue characteristics, and desired outcome.

  8. Preparation of reduced graphene oxide/gelatin composite films with reinforced mechanical strength

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenchao [School of Science, Tianjin University, Tianjin (China); Wang, Zhipeng [School of Science, Tianjin University, Tianjin (China); School of Chemical Engineering, Tianjin University, Tianjin (China); Liu, Yu; Li, Nan [School of Science, Tianjin University, Tianjin (China); Wang, Wei [School of Chemical Engineering, Tianjin University, Tianjin (China); Gao, Jianping, E-mail: jianpingg@eyou.com [School of Chemical Engineering, Tianjin University, Tianjin (China)

    2012-09-15

    Highlights: ► We used and compared different proportion of gelatin and chitosan as reducing agents. ► The mechanical properties of the films are investigated, especially the wet films. ► The cell toxicity of the composite films as biomaterial is carried out. ► The water absorption capabilities of the composite films also studied. -- Abstract: Graphene oxide (GO) was reduced by chitosan/gelatin solution and added to gelatin (Gel) to fabricate reduced graphene oxide/gelatin (RGO/Gel) films by a solvent-casting method using genipin as cross-linking agent. The structure and properties of the films were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and UV–vis spectroscopy. The addition of RGO increased the tensile strength of the RGO/Gel films in both dry and wet states, but decreased their elongation at break. The incorperation of RGO also decreased the swelling ability of the films in water. Cell cultures were carried out in order to test the cytotoxicity of the films. The cells grew and reproduced well on the RGO/Gel films, indicating that the addition of RGO has no negative effect on the compatibility of the gelatin. Therefore, the reduced graphene oxide/gelatin composite is a promising biomaterial with excellent mechanical properties and good cell compatibility.

  9. Preparation of sol-gel TiO2/purified Na-bentonite composites and their photovoltaic application for natural dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Saelim, Ni-on; Magaraphan, Rathanawan; Sreethawong, Thammanoon

    2011-01-01

    Highlights: → Natural dye from red cabbage was successfully employed in DSSC. → A fast sol-gel method to produce TiO 2 /clay thin film was proposed. → The sol-gel-prepared TiO 2 /clay was applied as the scattering layer on top of TiO 2 electrode. → Thicker sol-gel-prepared TiO 2 /clay electrode showed higher DSSC efficiency. - Abstract: The sol-gel TiO 2 /purified natural clay electrodes having Ti:Si molar ratios of 95:5 and 90:10 were initially prepared, sensitized with natural red cabbage dye, and compared to the sol-gel TiO 2 electrode in terms of physicochemical characteristics and solar cell efficiency. The results showed that the increase in purified Na-bentonite content greatly increased the specific surface area and total pore volume of the prepared sol-gel TiO 2 /purified Na-bentonite composites because the clay platelets prevented TiO 2 particle agglomeration. The sol-gel TiO 2 /5 mol% Si purified Na-bentonite and sol-gel TiO 2 /10 mol% Si purified Na-bentonite composites could increase the film thickness of solar cells without cracking when they were coated as a scattering layer on the TiO 2 semiconductor-based film, leading to increasing the efficiency of the natural dye-sensitized solar cells in this work.

  10. Demens Film

    DEFF Research Database (Denmark)

    Jensen, Anders Møller

    2012-01-01

    Vi vil skabe film til mennesker med demens – ikke film om demens sygdommen eller beretninger om livet og hverdagen med en kronisk lidelse. Filmene skal medvirke til at frembringe en behagelig stemning omkring og hos mennesker med demens, så hverdagen bliver så tryg som mulig. Filmene skal samtidig...... var at afgrænse og prioritere projektet, samt komme med anbefalinger omkring hvad der er vigtigt, i forbindelse med produktion af film målrettet mennesker med demens. Resultat af ekspertgruppen sammenfattes i denne rapport. Projektet gennemføres som et samarbejde mellem Retrospect Film...

  11. Cumulative irritation potential among metronidazole gel 1%, metronidazole gel 0.75%, and azelaic acid gel 15%.

    Science.gov (United States)

    Colón, Luz E; Johnson, Lori A; Gottschalk, Ronald W

    2007-04-01

    Topical therapy for rosacea aims to reduce inflammatory lesions and decrease erythema but can carry side effects such as stinging, pruritus, and burning. Metronidazole and azelaic acid gel 15% are U.S. Food and Drug Administration-approved for the treatment of rosacea. The current study was conducted to assess the cumulative irritation potential of 2 formulations of metronidazole 0.75% gel and 1% gel--and azelaic acid gel 15% over 21 days (N=36). Results of this study demonstrated a significantly greater poten tial for irritation from azelaic acid compared with metronidazole gel 0.75% (P < .0001), which had significantly greater potential for irritation compared with metronidazole gel 1% (P = .0054). Metronidazole gel 1% had a similar profile to white petrolatum.

  12. Nanocrystal/sol-gel nanocomposites

    Science.gov (United States)

    Klimov, Victor L.; Petruska, Melissa A.

    2010-05-25

    The present invention is directed to a process for preparing a solid composite having colloidal nanocrystals dispersed within a sol-gel matrix, the process including admixing colloidal nanocrystals with an amphiphilic polymer including hydrophilic groups selected from the group consisting of --COOH, --OH, --SO.sub.3H, --NH.sub.2, and --PO.sub.3H.sub.2 within a solvent to form an alcohol-soluble colloidal nanocrystal-polymer complex, admixing the alcohol-soluble colloidal nanocrystal-polymer complex and a sol-gel precursor material, and, forming the solid composite from the admixture. The present invention is also directed to the resultant solid composites and to the alcohol-soluble colloidal nanocrystal-polymer complexes.

  13. Bioinspired Programmable Polymer Gel Controlled by Swellable Guest Medium.

    Science.gov (United States)

    Deng, Heng; Dong, Yuan; Su, Jheng-Wun; Zhang, Cheng; Xie, Yunchao; Zhang, Chi; Maschmann, Matthew R; Lin, Yuyi; Lin, Jian

    2017-09-13

    Responsive materials with functions of forming three-dimensional (3D) origami and/or kirigami structures have a broad range of applications in bioelectronics, metamaterials, microrobotics, and microelectromechanical (MEMS) systems. To realize such functions, building blocks of actuating components usually possess localized inhomogeneity so that they respond differently to external stimuli. Previous fabrication strategies lie in localizing nonswellable or less-swellable guest components in their swellable host polymers to reduce swelling ability. Herein, inspired by ice plant seed capsules, we report an opposite strategy of implanting swellable guest medium inside nonswellable host polymers to locally enhance the swelling inhomogeneity. Specifically, we adopted a skinning effect induced surface polymerization combined with direct laser writing to control gradient of swellable cyclopentanone (CP) in both vertical and lateral directions of the nonswellable SU-8. For the first time, the laser direct writing was used as a novel strategy for patterning programmable polymer gel films. Upon stimulation of organic solvents, the dual-gradient gel films designed by origami or kirigami principles exhibit reversible 3D shape transformation. Molecular dynamics (MD) simulation illustrates that CP greatly enhances diffusion rates of stimulus solvent molecules in the SU-8 matrix, which offers the driving force for the programmable response. Furthermore, this bioinspired strategy offers unique capabilities in fabricating responsive devices such as a soft gripper and a locomotive robot, paving new routes to many other responsive polymers.

  14. Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation.

    Science.gov (United States)

    Gąsiorek, Jolanta; Szczurek, Anna; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

    2018-01-26

    Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

  15. Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

    Directory of Open Access Journals (Sweden)

    Jolanta Gąsiorek

    2018-01-01

    Full Text Available Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

  16. Microphase separation in nanocomposite gels

    Science.gov (United States)

    Osaka, Noboru; Endo, Hitoshi; Nishida, Toshihiko; Suzuki, Takuya; Li, Huan-Jun; Haraguchi, Kazutoshi; Shibayama, Mitsuhiro

    2009-06-01

    Microphase separation in poly( N -isopropylacrylamide)(PNIPA)-clay nanocomposite hydrogels (NC gels) is investigated by means of contrast-variation small-angle neutron scattering (CV-SANS) and dynamic light scattering (DLS). By using CV-SANS, it is revealed that microphase separation occurs in NC gels above the lower-critical solution temperature (LCST) of PNIPA aqueous solutions. The observed partial scattering functions show that only the spatial distribution of PNIPA chains is highly distorted by microphase separation and PNIPA chains are preferentially adsorbed on the clay surfaces, where the PNIPA-rich phase forms nanoscaled bicontinuous structure mediated by the clay particles. Additional DLS measurements for dilute solutions with PNIPA and/or the clay nanoparticles confirm that aggregation of PNIPA above the LCST is dramatically suppressed by addition of clay particles. Based on these observations, we conclude that strong affinity between the polymer and clay has a significant effect on the phase separation in NC gels and allows one to tune the length scale of the phase separation phenomenon by clay concentration.

  17. MRI gel dosimetry for verification of mono-isocentric junction doses in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Back, S.A.J.; Jayasekera, P.M.; Lepage, M.; Baldock, C.; Menzies, N.; Back, P.

    2000-01-01

    Full text: The use of independent collimators in the abutment of two adjacent treatment volumes, as in head and neck radiation treatments, consists typically of positioning the collimator rotation axis (CRA) at the junction of the volumes, and offsetting each field by its half-field width. This has the effect of positioning one of the collimator jaws at the CRA for each field. However, misalignment of the jaws can lead to variations in dose uniformity in the junction region. We have used gel dosimetry to measure junction doses in three dimensions. PAG gel MRI was used to investigate junction dosimetry for a mono-isocentriic treatment of two orthogonal pairs of opposed (ant/post and lateral) 6 MV x-ray beams. PAG gels in an 11cm diameter cylindrical gel phantom were imaged using a Siemens Vision 1.5 T MRI. The exposures were made using a Philips SL 20 linear accelerator with independent jaws that were known to overlap at the isocentre for sequential abutting offset (within manufacturer's specifications for symmetric fields). X-Omat V films were exposed in mono-directional beams, and optically scanned for comparison. Measurements of off-axis ratios and of relative depth profiles using gel MRI and perpendicular film were in excellent agreement with each other. Measurements through the multi-directional junction at the isocentre are illustrated in the graph, for orthogonal planes centred at the isocentre of the neck phantom. They demonstrate a minimum dose of 75 % of that of the adjacent 'treatment' regions, which agrees closely with the results measured (72%) in the mono-directional case with film. We conclude that this measurement confirms that junction dosimetry at the isocentre measured with perpendicular film for a single direction is a good approximation to the situation in multiple directions. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  18. New scale-down methodology from commercial to lab scale to optimize plant-derived soft gel capsule formulations on a commercial scale.

    Science.gov (United States)

    Oishi, Sana; Kimura, Shin-Ichiro; Noguchi, Shuji; Kondo, Mio; Kondo, Yosuke; Shimokawa, Yoshiyuki; Iwao, Yasunori; Itai, Shigeru

    2018-01-15

    A new scale-down methodology from commercial rotary die scale to laboratory scale was developed to optimize a plant-derived soft gel capsule formulation and eventually manufacture superior soft gel capsules on a commercial scale, in order to reduce the time and cost for formulation development. Animal-derived and plant-derived soft gel film sheets were prepared using an applicator on a laboratory scale and their physicochemical properties, such as tensile strength, Young's modulus, and adhesive strength, were evaluated. The tensile strength of the animal-derived and plant-derived soft gel film sheets was 11.7 MPa and 4.41 MPa, respectively. The Young's modulus of the animal-derived and plant-derived soft gel film sheets was 169 MPa and 17.8 MPa, respectively, and both sheets showed a similar adhesion strength of approximately 4.5-10 MPa. Using a D-optimal mixture design, plant-derived soft gel film sheets were prepared and optimized by varying their composition, including variations in the mass of κ-carrageenan, ι-carrageenan, oxidized starch and heat-treated starch. The physicochemical properties of the sheets were evaluated to determine the optimal formulation. Finally, plant-derived soft gel capsules were manufactured using the rotary die method and the prepared soft gel capsules showed equivalent or superior physical properties compared with pre-existing soft gel capsules. Therefore, we successfully developed a new scale-down methodology to optimize the formulation of plant-derived soft gel capsules on a commercial scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Trace Contaminant Control: An In-Depth Study of a Silica-Titania Composite for Photocatalytic Remediation of Closed-Environment Habitat Air

    Science.gov (United States)

    Coutts, Janelle L.

    2013-01-01

    This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-TiO2 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp O max=365 nm) at its maximum light intensity or a UV-C germicidal lamp O. max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1 ) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol C02 mol photons-1 ). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy. The effect of temperature and relative humidity on the STC-catalyzed degradation of ethanol was also determined using the UV-A light source at its maximum intensity.

  20. Water equivalence of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sellakumar, P.; James Jebaseelan Samuel, E.; Supe, Sanjay S.

    2007-01-01

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z eff ), electron density (ρ e ), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μ en /ρ) and total stopping power (S/ρ) tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close ( en /ρ for all polymer gels were in close agreement ( tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  1. Comparison of the Remineralizing Effects of Sodium Fluoride and Bioactive Glass Using Bioerodible Gel Systems

    Directory of Open Access Journals (Sweden)

    Attiguppe Ramashetty Prabhakar

    2009-12-01

    Full Text Available Background and aims. A carious lesion is the accumulation of numerous episodes of de- and remineralization, rather than a unidirectional demineralization process. Tooth destruction can be arrested or reversed by the frequent delivery of fluoride or calcium/phosphorous ions to the tooth surface. The present study compared and evaluated the remineralization potential of sodium fluoride and bioactive glass delivered through a bioerodible gel system. Materials and methods. Longitudinal sections of artificial carious lesions, created at the gingivofacial surface of 64 primary maxillary incisors were photographed under a polarized light microscope and quantified for demineralization. The sections were repositioned into the tooth form and randomly mounted in sets of four that simulated an arch form. The teeth were divided into 4 groups: 1 sodium fluoride films, 2 bioactive glass films, 3 control films placed interproximally and 4 nontreatment group. Following exposure to artificial saliva for 30 days, the lesions were again photographed and quantified as above. The recorded values were statistically analyzed using Student’s paired t-test for intragroup comparison, one-way ANOVA and Post-Hoc Tukey’s test for pairwise comparison. Results. The sodium fluoride and bioactive gel groups showed significant remineralization compared with the control groups (P < 0.001. Conclusion. Bioerodible gel films can be used to deliver remineralizing agents to enhance remineralization.

  2. Into films

    DEFF Research Database (Denmark)

    Tan, Ed S.; Doicaru, Miruna M.; Hakemulder, Frank

    2017-01-01

    Most film viewers know the experience of being deeply absorbed in the story of a popular film. It seems that at such moments they lose awareness of watching a movie. And yet it is highly unlikely that they completely ignore the fact that they watch a narrative and technological construction...

  3. Aspects of dosimetry using radiation sensitive gels

    International Nuclear Information System (INIS)

    Baldock, Clive

    2001-01-01

    The use of radiation sensitive gels for dosimetry measurements was first suggested in the 1950s. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. However, due to predominantly diffusion-related limitations, alternative polymer gel dosimeters were suggested. Clinical applications of these radiologically tissue equivalent gel dosimeters using magnetic resonance imaging (MRI) have subsequently been reported in the literature. In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin or agarose hydrogel matrix. Radiation-induced changes in the dosimeters are considered to be either through direct absorption of ionising radiation or via intermediate water free radicals. Fe 2+ ions are converted to Fe 3+ ions with a corresponding change in paramagnetic properties that may be quantified using NMR relaxation measurements. In polymer gels, monomers are also dispersed in a gelatin or agarose hydrogel matrix. Monomers undergo a polymerisation reaction as a function of absorbed dose resulting in a three-dimensional polymer gel matrix. The radiation-induced formation of polymer influences NMR relaxation properties. The growth in polymer also results in other physical changes that may be used to quantify absorbed radiation dose. This thesis investigates various aspects of radiation dosimetry using radiation sensitive gels. Image processing software was developed to calculate NMR relaxation images of dosimetry gels. Measurements were undertaken to investigate the diffusion problem in Fricke gels. Radiological properties were theoretically modelled for both Fricke and polymer gels. A methodology was developed for the preparation of polymer gels. Vibrational spectroscopic studies were undertaken to investigate the underlying mechanism involved in the radiation-induced formation of polymer. MRI

  4. The Influence of Conditioning Agent on Phosphate Diffusion Coefficient through Polyacrylamide and Agarose Gel

    Directory of Open Access Journals (Sweden)

    Layta Dinira

    2013-03-01

    Full Text Available Excess phosphate in natural water can cause algae grow rapidly, to the extent causing many fish deaths that led to the extinction of certain species. Therefore, an analysis or periodic observations of phosphate levels in the water is needed. The commonly used method is diffusive gradient in thin films (DGT technique. The DGT technique is based on the ability of analyte to diffuse through a gel, which have a value named diffusion coefficient. This research was conducted in order to study the effect of different storage solution to the phosphate diffusion coefficient through polyacrylamide and agarose gels. Initial research performed with making the polyacrylamide and agarose gels. To observe the effect of different storage solutions, the gels partly stored in distilled water gel while the others are stored in a NaCl solution of 0.01 M. Phosphate diffusion coefficient was determined using Fick's Law after analyze the phosphate concentration using UV-Visible spectrophotometer. The results showed that phosphate diffusion coefficient was highest when polyacrylamide and agarose gels stored in NaCl solution of 0.01 M.

  5. Properties of TiO2 films with gold nanoparticles

    International Nuclear Information System (INIS)

    Aliev, S A; Nikolaev, N E; Trofimov, N S; Chekhlova, T K

    2016-01-01

    The physicochemical and optical properties of titanium dioxide films, made by gel technology and doped with gold nanoparticles, were investigated. The structures of the titanium dioxide films synthesized by different techniques have been compared. Using methods of high-resolution microscopy and the results of X-ray diffraction analysis it was shown, that the developed gel technology allows getting almost 100% nanostructured anatase phase. Titanium dioxide was modified by nanoparticles of gold with different concentration and transmittance spectra of the samples were studied. (paper)

  6. Large area ceramic thin films on plastics: A versatile route via solution processing

    Science.gov (United States)

    Kozuka, H.; Yamano, A.; Fukui, T.; Uchiyama, H.; Takahashi, M.; Yoki, M.; Akase, T.

    2012-01-01

    A new general route for large area, submicron thick ceramic thin films (crystalline metal oxide thin films) on plastic substrates is presented, where the crystallization of films is guaranteed by a firing process. Gel films are deposited on silicon substrates with a release layer and fired to be ceramic films, followed by transferring onto plastic substrates using adhesives. The ceramic films thus fabricated on plastics exhibit a certain degree of flexibility, implying the possibility of the technique to be applied to high-throughput roll-to-roll processes. Using this technique, we successfully realized transparent anatase thin films that provide high optical reflectance and transparent indium tin oxide thin films that exhibit electrical conductivity on polycarbonate and acrylic resin substrates, respectively. Crystallographically oriented zinc oxide films and patterned zinc oxide films are also demonstrated to be realized on acrylic resin substrates.

  7. Rheological characterization of Poloxamer 407 nimesulide gels

    Directory of Open Access Journals (Sweden)

    M. N. Freitas

    2009-01-01

    Full Text Available The thermal gelling property of Poloxamer 407- nimesulide gels was characterized by rheological studies. Nimesulide, a local anti-inflammatory and anesthetic drug used for the treatment of acute and chronic pain, has a short duration of action and a long-acting single-dose injection would be of clinical importance. Thus a poloxamer 407 gel applied intramuscularly could prolong the release and action of nimesulide. In this study, aqueous gels with nimesulide, containing three different concentrations of Poloxamer 407, were prepared. Viscosity measurements were performed by rheologial studies to obtain the optimal sol-gel transition temperature . Poloxamer 407 gels are pseudoplastic and viscoelastic materials, which have an elastic modulus (G', characteristic of the solid, and a viscous modulus (G'', characteristic of the liquid material. Moreover, being pseudoplastic gels, when they are deformed by shearing, their viscosity decreases. Increase of the polymer concentration increased the viscosity of the gels, which could affect the releasing process of nimesulide. Furthermore, the presence of nimesulide led to a lowering of the sol-gel transition temperature. Keywords: Poloxamer 407 gels; nimesulide; rheological characterization; viscosity; sol-gel transition temperature.

  8. Sol-gel derived fluor-hydroxyapatite biocoatings on zirconia substrate.

    Science.gov (United States)

    Kim, Hae-Won; Kong, Young-Min; Bae, Chang-Jun; Noh, Yoon-Jung; Kim, Hyoun-Ee

    2004-07-01

    Fluor-hydroxyapatite (FHA) film was coated on a zirconia (ZrO(2)) substrate by a sol-gel method. An appropriate amount of F ions was incorporated into the hydroxyapatite (HA) during the preparation of the sols. The apatite phase began to crystallize after heat treatment at 400 degrees C, and increased in intensity above 500 degrees C. No decomposition was detected by X-ray diffraction analyses up to 800 degrees C, which illustrates the high thermal stability of the FHA films. The films showed a uniform and dense morphology with a thickness of approximately 1 microm after a precisely controlled heat treatment process. These FHA films adhered firmly to the zirconia substrate, representing notable adhesion strengths of approximately 70 MPa after heat treatment above 500 degrees C. The dissolution rate of the FHA coating layer varied according to the heat treatment temperature, which was closely related to the film crystallinity. The dissolution rate of the FHA film was lower than that of the HA film, suggesting the possibility of a functional gradient coating of HA and FHA. The MG63 cells seeded onto the FHA films proliferated in a similar manner to those seeded onto pure HA ceramic and a plastic control.

  9. Demens Film

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2012-01-01

    I forbindelse med opstarten af Demens Film projektet har der været nedsat en ekspertgruppe, som er kommet med en række anbefalinger omkring film til mennesker med demens. Anbefalingerne skal bruges i de næste faser af projektet. Deltagerne i ekspertgruppen var sammensat af en bred gruppe...... fagpersoner inde for forskellige fagområder. Læs mere om gruppens anbefalinger og sammensætning af ekspertgruppen i den kort rapport som er offentlig tilgængelig. Læs Ekspertgruppe anbefalingerne til Demens Film projekt....

  10. Formation of single-walled carbon nanotube thin films enriched with semiconducting nanotubes and their application in photoelectrochemical devices.

    Science.gov (United States)

    Wei, Li; Tezuka, Noriyasu; Umeyama, Tomokazu; Imahori, Hiroshi; Chen, Yuan

    2011-04-01

    Single-walled carbon nanotube (SWCNT) thin films, containing a high-density of semiconducting nanotubes, were obtained by a gel-centrifugation method. The agarose gel concentration and centrifugation force were optimized to achieve high semiconducting and metallic nanotube separation efficiency at 0.1 wt% agarose gel and 18,000g. The thickness of SWCNT films can be precisely controlled from 65 to 260 nm with adjustable transparency. These SWCNT films were applied in photoelectrochemical devices. Photocurrents generated by semiconducting SWCNT enriched films are 15-35% higher than those by unsorted SWCNT films. This is because of reducing exciton recombination channels as a result of the removal of metallic nanotubes. Thinner films generate higher photocurrents because charge carriers have less chances going in metallic nanotubes for recombination, before they can reach electrodes. Developing more scalable and selective methods for high purity semiconducting SWCNTs is important to further improve the photocurrent generation efficiency by using SWCNT-based photoelectrochemical devices.

  11. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...... enriched dairy products. Calcium gels can be produced by addition of a calcium salt and heat treatment at temperatures higher than 70 oC for several minutes. The combination of heat treatment and calcium addition to milk with pH values between 6.6 and 5.6, will produce calcium milk gels with unique...... to be formed. In addition the low amount of micellar calcium caused a more compact gel structure with many protein aggregates. The results of this study highlighted the importance of calcium for the formation of acid, calcium and rennet gels. The content and the interactions of calcium with proteins during...

  12. Tunable Gas Sensing Gels by Cooperative Assembly.

    Science.gov (United States)

    Hussain, Abid; Semeano, Ana T S; Palma, Susana I C J; Pina, Ana S; Almeida, José; Medrado, Bárbara F; Pádua, Ana C C S; Carvalho, Ana L; Dionísio, Madalena; Li, Rosamaria W C; Gamboa, Hugo; Ulijn, Rein V; Gruber, Jonas; Roque, Ana C A

    2017-07-19

    The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.

  13. Research on pre-staining gel electrophoresis

    International Nuclear Information System (INIS)

    Zhong Ruibo; Liu Yushuang; Zhang Ping; Liu Jingran; Zhao Guofen; Zhang Feng

    2014-01-01

    Background: Gel electrophoresis is a powerful biochemical separation technique. Most biological molecules are completely transparent in the visible region of light, so it is necessary to use staining to show the results after gel electrophoresis, and the general steps of conventional staining methods are time-consuming. Purpose: We try to develop a novel approach to simplify the gel electrophoresis: Pre-Staining Gel Electrophoresis (PSGE), which can make the gel electrophoresis results monitored in real time. Methods: Pre-stain the protein samples with Coomassie Brilliant Blue (CBB) for 30 min before loading the sample into the gel well. Results and Conclusion: PSGE can be successfully used to analyze the binding efficiency of Bovine Serum Albumin (BSA) and amphiphilic polymer via chemical coupling and physical absorption, and the double PSGE also shows a great potential in bio-analytical chemistry. (authors)

  14. Self-Pumping Active Gel

    Science.gov (United States)

    Wu, Kun-Ta; Hishamunda, Jean Bernard; Fraden, Seth; Dogic, Zvonimir

    Isotropic active gels are the network which is consist of cross-linked building blocks and the structure of which changes randomly and isotropically with time. Dogic et. al. show that pairs of anti-parallel microtubules form extensile bundles, which merge, extend, and buckle. In an unconfined system, the dynamics of these bundles causes spontaneous turbulent-like flow driven by motion of microscopic molecular motors. We found that confining these active gels in a millimeter sized toroids causes a transition into a new dynamical state characterized by circulation currents persisting for hours until ATP is depleted. We show how toroid dimensions impact the properties of self-organized circular currents, how directions of circulation can be designed by engineering ratchet-shaped boundaries, and how circulations of connected toroids can be either synchronized or antisynchronized. Furthermore, we demonstrate that the flow rate in the circulation is independent of curvature and length of flow path. The flow rate persists for centimeters without decay, disregarding conventional pipe flow resistance. Such findings pave the path to self-pumping pipe transport and performing physical work with biological system.

  15. Microfluidics of soft granular gels

    Science.gov (United States)

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  16. Stabilized aqueous gels and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, B.L.

    1978-08-29

    New improved aqueous gels, and methods of using same in contacting subterranean formations, are provided. The gels are prepared by gelling an aqueous brine having incorporated therein a water-soluble cellulose ether such as a carboxymethylcellulose (CMC), and are rendered more stable to decomposition by incorporating a sulfoalkylated tannin stabilizing agent, such as a sulfomethylated quebracho (SMQ), in the gel during the preparation thereof.

  17. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  18. KMCThinFilm: A C++ Framework for the Rapid Development of Lattice Kinetic Monte Carlo (kMC) Simulations of Thin Film Growth

    Science.gov (United States)

    2015-09-01

    196–201. 44. Kratzer P. Monte Carlo and kinetic Monte Carlo methods–a tutorial. In: Grotendorst J, Attig N, Blügel S, Marx D, editors. Multiscale...Monte Carlo (kMC) Simulations of Thin Film Growth by James J Ramsey Approved for public release; distribution is...Research Laboratory KMCThinFilm: A C++ Framework for the Rapid Development of Lattice Kinetic Monte Carlo (kMC) Simulations of Thin Film Growth by

  19. Fluor-hydroxyapatite sol-gel coating on titanium substrate for hard tissue implants.

    Science.gov (United States)

    Kim, Hae-Won; Kim, Hyoun-Ee; Knowles, Jonathan C

    2004-08-01

    Hydroxyapatite (HA) and fluor-hydroxyapatite (FHA) films were deposited on a titanium substrate using a sol-gel technique. Different concentrations of F- were incorporated into the apatite structure during the sol preparation. Typical apatite structures were obtained for all coatings after dipping and subsequent heat treatment at 500 degrees C. The films obtained were uniform and dense, with a thickness of approximately 5 microm. The dissolution rate of the coating layer decreased with increasing F- incorporation within the apatite structure, which demonstrates the possibility of tailoring the solubility by a functional gradient coating of HA and FHA. The cell proliferation rate on the coating layer decreased slightly with increasing F- incorporation. The alkaline phosphatase (ALP) activity of the cells on all the HA and FHA coated samples showed much higher expression levels compared to pure Ti. This confirmed the improved activity of cell functions on the substrates with the sol-gel coating treatment.

  20. Proceedings of the international conference on sol-gel processes for advanced ceramics

    International Nuclear Information System (INIS)

    Vaidya, V.N.; Kumar, N.

    2009-01-01

    Sol-gel science and technology plays an important role in the synthesis of a wide range of materials. viz., fine ceramics, glasses, thin films, aerogels, nanomaterials of controlled composition and shape. speciality products such as nuclear fuels and industrial catalysts and so on. The products are homogeneous, and the synthesis and fabrication processes occur at significantly lower temperatures when compared to the conventional solid state reactions. The objective of the present International Conference on Sol-Gel Processes for Advanced Ceramics (SGPAC-2009) is to consolidate the knowledge on the wide spectrum applications of the sol-gel processes in materials synthesis and fabrication with special emphasis on ceramics. The aim is to bring together specialists from research groups across the globe to discuss the state of the art, and facilitate exchange of ideas. The articles relevant to INIS are indexed separately

  1. Ionic liquid based multifunctional double network gel

    Science.gov (United States)

    Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

    2015-04-01

    Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

  2. Gel catalysts that switch on and off

    Science.gov (United States)

    Wang, Guoqiang; Kuroda, Kenichi; Enoki, Takashi; Grosberg, Alexander; Masamune, Satoru; Oya, Taro; Takeoka, Yukikazu; Tanaka, Toyoichi

    2000-01-01

    We report development of a polymer gel with a catalytic activity that can be switched on and off when the solvent composition is changed. The gel consists of two species of monomers. The major component, N-isopropylacrylamide, makes the gel swell and shrink in response to a change in composition of ethanol/water mixtures. The minor component, vinylimidazole, which is capable of catalysis, is copolymerized into the gel network. The reaction rate for catalytic hydrolysis of p-nitrophenyl caprylate was small when the gel was swollen. In contrast, when the gel was shrunken, the reaction rate increased 5 times. The activity changes discontinuously as a function of solvent composition, thus the catalysis can be switched on and off by an infinitesimal change in solvent composition. The kinetics of catalysis by the gel in the shrunken state is well described by the Michaelis–Menten formula, indicating that the absorption of the substrate by the hydrophobic environment created by the N-isopropylacrylamide polymer in the shrunken gel is responsible for enhancement of catalytic activity. In the swollen state, the rate vs. active site concentration is linear, indicating that the substrate absorption is not a primary factor determining the kinetics. Catalytic activity of the gel is studied for substrates with various alkyl chain lengths; of those studied the switching effect is most pronounced for p-nitrophenyl caprylate. PMID:10954747

  3. Conducting polymer electrodes for gel electrophoresis.

    Directory of Open Access Journals (Sweden)

    Katarina Bengtsson

    Full Text Available In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene (PEDOT can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  4. Conducting polymer electrodes for gel electrophoresis.

    Science.gov (United States)

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  5. Soft nanoimprint lithography on SiO2 sol-gel to elaborate sensitive substrates for SERS detection

    Science.gov (United States)

    Hamouda, Frédéric; Bryche, Jean-François; Aassime, Abdelhanin; Maillart, Emmanuel; Gâté, Valentin; Zanettini, Silvia; Ruscica, Jérémy; Turover, Daniel; Bartenlian, Bernard

    2017-12-01

    This paper presents a new alternative fabrication of biochemical sensor based on surface enhanced Raman scattering (SERS) by soft nanoimprint lithography (S-NIL) on SiO2 sol-gel. Stabilization of the sol-gel film is obtained by annealing which simplifies the manufacturing of these biosensors and is compatible with mass production at low cost. This detector relies on a specific pattern of gold nanodisks on a thin gold film to obtain a better sensitivity of molecules' detection. Characterizations of SERS devices were performed on a confocal Raman microspectrophotometer after a chemical functionalization. We report a lateral collapse effect on poly(diméthylsiloxane) (PDMS) stamp for specific nanostructure dimensions. This unintentional effect is used to evaluate S-NIL resolution in SiO2 sol-gel.

  6. Electrochemical behaviour of ceramic yttria stabilized zirconia on carbon steel synthesized via sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, M.A. Dominguez, E-mail: mdominguezc@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Murillo, A. Garcia; Torres-Huerta, A.M. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Yanez-Zamora, C. [Estudiante del postgrado en Tecnologia Avanzada del CICATA-IPN, Unidad Altamira, km 14.5, Carr. Tampico-Puerto Industrial. C.P. 89600, Altamira, Tamaulipas (Mexico); Carrillo-Romo, F. de J [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico)

    2009-08-26

    Chromate conversion coatings have been widely applied for the corrosion of different metallic substrates. However, the waste containing Cr{sup 6+} has many limitations due to the environmental consideration and health hazards. An interesting alternative seems to be the deposition on metallic surface of thin layers of yttria or zirconia or both by the sol-gel process. In this study, Ytttria and Yttria stabilized zirconia (YSZ, 8% Y{sub 2}O{sub 3}) thin films were used for coating commercial carbon steel substrates by sol-gel method and the dip-coating process. The evolution of organic compounds up to crystallization process as a function of heat treatments was study by FT-IR spectroscopy. The structure and morphology of the coatings were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The anticorrosion performance of the coatings has been evaluated by using electrochemical techniques in an aggressive media (3.5 wt.% NaCl). The corrosion behaviour of sol-gel method was compared with traditional chromate conversion coatings. Differences in the electrochemical behaviour of YSZ coatings are related to the development of microcracks during the sintering process and to the presence of organic compounds during growth film. Electrochemical results showed that sol-gel YSZ and Y{sub 2}O{sub 3} coatings can act as protective barriers against wet corrosion; however yttria films displayed low adhesion to substrate. The corrosion parameters provide an explanation of the role of each film and show a considerable increase in the corrosion resistance for coated samples in comparison to the bare steel samples.

  7. Role of reaction atmosphere in preparation of potassium tantalate through sol-gel method

    Czech Academy of Sciences Publication Activity Database

    Buršík, Josef; Vaněk, Přemysl; Mika, Filip

    2013-01-01

    Roč. 68, č. 2 (2013), s. 219-233 ISSN 0928-0707 R&D Projects: GA ČR GA13-03708S; GA MŠk ED0017/01/01 Institutional support: RVO:61388980 ; RVO:68378271 ; RVO:68081731 Keywords : Potassium tantalate * thin films * Sol-gel * crystallization * reaction atmosphere Subject RIV: CA - Inorganic Chemistry; JA - Electronics ; Optoelectronics, Electrical Engineering (UPT-D) Impact factor: 1.547, year: 2013

  8. Study of optical characteristics of tin oxide thin film prepared by sol ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present details of preparation of tin oxide (SnO2) thin film by sol–gel process. The film was synthesized on a glass (Corning 7059) plate by dip coating method. Here, we used tin (II) chloride as precursor and methanol as solvent. Optical characteristics and physical properties like refractive index, ...

  9. Design and evaluation of buccal films as paediatric dosage form for transmucosal delivery of ondansetron.

    Science.gov (United States)

    Trastullo, Ramona; Abruzzo, Angela; Saladini, Bruno; Gallucci, Maria Caterina; Cerchiara, Teresa; Luppi, Barbara; Bigucci, Federica

    2016-08-01

    In the process of implementation and innovation of paediatric dosage forms, buccal films for transmucosal administration of drug represent one of the most interesting approach. In fact, films are able to provide an extended duration of activity allowing minimal dosage and frequency and offer an exact and flexible dose, associated with ease of handling. The objective of the present study was to develop polymeric films for the sustained release of ondansetron hydrochloride, a selective inhibitor of 5-HT3 receptors indicated in paediatrics for the prevention and treatment of nausea and vomiting caused by cytotoxic chemotherapy or radiotherapy and postoperatively. Films were prepared by casting and drying of aqueous solutions containing different weight ratios of hydroxypropylmethylcellulose (HPMC) with chitosan (CH) or sodium hyaluronate (HA) or gelatin (GEL) and characterized for their physico-chemical and functional properties. The presence of HA, GEL and CH did not improve the mucoadhesive properties of HPMC film. The inclusion of GEL and CH in HPMC film increased in vitro drug release with respect to the inclusion of HA, although films containing HA showed the highest water uptake. Moreover in agreement with the release behaviour, the inclusion of CH and GEL provided higher drug permeation through porcine buccal mucosa with respect to HPMC film and ensured linear permeation profiles of drug. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Nanostructure Development in Alkoxide-Carboxylate-Derived Precursor Films of Barium Titanate

    NARCIS (Netherlands)

    Stawski, Tomasz; Veldhuis, Sjoerd; Besselink, R.; Castricum, H.L.; Portale, G.; Blank, David H.A.; ten Elshof, Johan E.

    2012-01-01

    The structural evolution in wet alkoxide-carboxylate sol–gel precursor films of barium titanate upon drying was investigated by time-resolved small-angle X-ray scattering (SAXS). The morphology of as-dried amorphous precursor thin films was investigated by transmission electron microscopy (TEM) and

  11. Preparation and characterization of nanostructured ZnO thin films for ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Nanostructured zinc oxide thin films (ZnO) were prepared on conducting glass support (SnO2: F overlayer) via sol–gel starting from colloidal solution of zinc acetate 2-hydrate in ethanol and 2-methoxy ethanol. Films were obtained by spin coating at 1500 rpm under room conditions (temperature, 28–35°C) and.

  12. Preparation of high dielectric constant thin films of CaCu3 Ti4 O12 ...

    Indian Academy of Sciences (India)

    Preparation of sol–gel derived CaCu3Ti4O12 (CCTO) thin films using two different sols and their characterization including their dielectric response are reported. The properties of CCTO films depend heavily on solvents used to prepare the sols. Dielectric constant as high as ∼900 at 100 kHz could be obtained when acetic ...

  13. A facile method for the density determination of ceramic thin films using X-ray reflectivity

    NARCIS (Netherlands)

    Veldhuis, Sjoerd; Brinks, Peter; Stawski, Tomasz; Göbel, Ole; ten Elshof, Johan E.

    2014-01-01

    A fast and non-destructive method based on X-ray reflectivity was developed to determine the density of sol–gel derived ceramic thin films, without prior assumptions on the microstructure of the system. The thin film density is calculated from the critical angle θc, i.e. the maximum angle at which

  14. Process dependence of the piezoelectric response of membrane actuators based on PZT thin films

    NARCIS (Netherlands)

    Nguyen, C.T.Q.; Nguyen, Duc Minh; Dekkers, Jan M.; Houwman, Evert Pieter; Vu, Hung Ngoc; Rijnders, Augustinus J.H.M.

    2014-01-01

    A process for the fabrication of piezoelectric membranes with Pb(Zr0.45Ti0.55)O3 (PZT) thin films for micrometer-range actuation and sensing applications has been developed. The films grown by sol-gel on the Pt/Ti/SiO2/SOI (silicon-on-insulator) substrates have similar randomly oriented perovskite

  15. Foldable and Cytocompatible Sol-gel TiO2 Photonics.

    Science.gov (United States)

    Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B; Geiger, Sarah J; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

    2015-09-07

    Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices.

  16. The spatial resolution in dosimetry with normoxic polymer-gels investigated with the dose modulation transfer approach

    International Nuclear Information System (INIS)

    Bayreder, Christian; Schoen, Robert; Wieland, M.; Georg, Dietmar; Moser, Ewald; Berg, Andreas

    2008-01-01

    The verification of dose distributions with high dose gradients as appearing in brachytherapy or stereotactic radiotherapy for example, calls for dosimetric methods with sufficiently high spatial resolution. Polymer gels in combination with a MR or optical scanner as a readout device have the potential of performing the verification of a three-dimensional dose distribution within a single measurement. The purpose of this work is to investigate the spatial resolution achievable in MR-based polymer gel dosimetry. The authors show that dosimetry on a very small spatial scale (voxel size: 94x94x1000 μm 3 ) can be performed with normoxic polymer gels using parameter selective T2 imaging. In order to prove the spatial resolution obtained we are relying on the dose-modulation transfer function (DMTF) concept based on very fine dose modulations at half periods of 200 μm. Very fine periodic dose modulations of a 60 Co photon field were achieved by means of an absorption grid made of tungsten-carbide, specifically designed for quality control. The dose modulation in the polymer gel is compared with that of film dosimetry in one plane via the DMTF concept for general access to the spatial resolution of a dose imaging system. Additionally Monte Carlo simulations were performed and used for the calculation of the DMTF of both, the polymer gel and film dosimetry. The results obtained by film dosimetry agree well with those of Monte Carlo simulations, whereas polymer gel dosimetry overestimates the amplitude value of the fine dose modulations. The authors discuss possible reasons. The in-plane resolution achieved in this work competes with the spatial resolution of standard clinical film-scanner systems

  17. Preparation of continuous alumina gel fibres by aqueous sol–gel ...

    Indian Academy of Sciences (India)

    sol–gel process using aluminum-tri-isopropoxide as starting materials, and Shojaie-Bahaabad et al (2008) synthesized composite fibres (YAG/Al2O3) from an aqueous solution of aluminum powder, aluminum chloride hexahydrate and yttrium oxide by the sol–gel method. But, the preparation processes of continuous gel ...

  18. Dielectric properties of PMMA-SiO2 hybrid films

    KAUST Repository

    Morales-Acosta, M. D.

    2010-03-01

    Organic-inorganic hybrid films were synthesized by a modified sol-gel process. PMMASiO2 films were prepared using methylmethacrylate (MMA), tetraethil-orthosilicate (TEOS) as silicon dioxide source, and 3-trimetoxi-silil-propil-methacrylate (TMSPM) as coupling agent. FTIR measurements were performed on the hybrid films to confirm the presence of PMMA-SiO2 bonding. In addition, metal-insulator-metal (MIM) devices were fabricated to study the dielectric constant of the films as function of frequency (1 KHz to 1 MHz). Electrical results show a weak trend of the dielectric constant of the hybrid films with MMA molar ratio. More importantly, the PMMA-SiO2 hybrid films showed a higher dielectric constant than SiO2 and PMMA layers, which is likely due to the presence of additional C-O-C bond. © (2010) Trans Tech Publications.

  19. Topological characteristics of model gels

    International Nuclear Information System (INIS)

    Miller, Mark A; Hansen, Jean-Pierre; Blaak, Ronald

    2010-01-01

    The Euler characteristic of an object is a topological invariant determined by the number of handles and holes that it contains. Here, we use the Euler characteristic to profile the topology of model three-dimensional gel-forming fluids as a function of increasing length scale. These profiles act as a 'topological fingerprint' of the structure, and can be interpreted in terms of three types of topological events. As model fluids we have considered a system of dipolar dumbbells, and suspensions of adhesive hard spheres with isotropic and patchy interactions in turn. The correlation between the percolation threshold and the length scale on which the Euler characteristic passes through zero is examined and found to be system-dependent. A scheme for the efficient calculation of the Euler characteristic with and without periodic boundary conditions is described.

  20. Chitosan: Gels and Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.