共查询到20条相似文献,搜索用时 31 毫秒
1.
I. Ruiz de Larramendi R. López Antón J.I. Ruiz de Larramendi S. Baliteau F. Mauvy J.C. Grenier T. Rojo 《Journal of power sources》2007
Pr0.8Sr0.2Fe0.8Ni0.2O3−δ (PN22) films have been deposited at different temperatures on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes. The structure of the films was analysed by X-ray diffraction (XRD) and atomic force microscopy (AFM). A marked influence in the structural properties of the substrate temperature has been found but not of the composition. Samples deposited at temperatures below 700 °C are amorphous, with granular aspect, and with decreasing roughness with the temperature. Meanwhile, the films at 700 °C are polycrystalline and exhibit a needle-shaped surface, with the highest roughness observed. Additionally, the conducting behaviour of the films has been studied by electrochemical impedance spectroscopy (EIS) and their cathodic area specific resistance (ASR) was determined. The main part of the impedance of the testing cells is due to the electrode. The ASR values of the films of PN22 are lower than those of Pr0.9Sr0.1Fe0.8Ni0.2O3−δ (PN12), being the lowest 0.5 Ω cm2 at 850 °C for the sample PN22 deposited at room temperature. 相似文献
2.
O. Bamiduro 《Solar Energy》2011,85(3):545-552
CuIn(1−x)GaxSe2 (CIGS) thin films were prepared by one-step electro-deposition technique from a salt bath coupled with thiocyanate complex electrolytes followed by annealing in argon atmosphere at 300 °C. The influence of deposition reduction potentials as well as the salt concentrations on the structure, morphology, composition and the optical properties were performed. A reproducible Cu-In-Ga-Se precursor layer deposition with consistent composition control was demonstrated. The as-deposited films exhibit an amorphous behavior; however the films displayed good crystallization after annealing. The films show very uniform and dense grain formation with platelet-like nanostructures. The optical properties of the films are modified due to annealing. The electrical conductivity measurements demonstrate that the transport mechanism is influenced by three different temperature regions: the ionization, extrinsic and intrinsic regions, respectively, as found in other semiconductors. However, the annealed films display downturn in conductivity at low temperature indicating that there may be trapping at localized sites or scattering of the free carriers, which may be attributed to the over growth and defect sites. The electro-deposition technique demonstrates promise of growing high-quality CIGS thin films. 相似文献
3.
M. Venkatachalam M.D. Kannan S. Jayakumar R. Balasundaraprabhu A.K. Nandakumar N. Muthukumarasamy 《Solar Energy Materials & Solar Cells》2008,92(5):571-575
CuInxGa1−xSe2 bulk compound of three different compositions x=0.75, 0.80 and 0.85 have been prepared using individual elements of copper, indium, gallium and selenium. Thin films of CuInxGa1−xSe2 have been deposited using the prepared bulk by electron beam evaporation method. The structural studies carried on the deposited films revealed that films annealed at 400 °C are crystalline in nature exhibiting chalcopyrite phase. The position of the (1 1 2) peak in the X-ray diffractogram corresponding to the chalcopyrite phase has been found to be dependent on the percentage of gallium in the films. The composition of the prepared bulk and thin films has been identified using energy dispersive X-ray analysis. The photoluminescence spectra of the CuInxGa1−xSe2 films exhibited sharp luminescence peaks corresponding to the band gap of the material. 相似文献
4.
Peroxo-polymolybdovanadates with various mole ratios of Mo/V are formed by direct reaction of a mixture of metallic Mo and V with hydrogen peroxide solution. Homogeneous amorphous thin films about 0.4 μm are fabricated on an ITO glass substrate by a spin-coating technique using the peroxo-polymolybdovanadate solutions. After heat-treatment at a desired temperature (80–120°C) in air for 1 h, they show reversible electrochromism in an organic Li-electrolyte solution, and change color between greenish yellow and violet. The potential (E) versus composition (x, Li content per mole of MoyV1−yOz) diagrams for these mixed films could be approximated by two straight lines with different slopes, which suggests that in these films there are two kinds of sites with different site energies. The changes in electrochromism with heat-treatment are also discussed in relation to the micro-structure of the films. 相似文献
5.
Polycrystalline CuIn0.7Ga0.3Se2 thin films were prepared on soda-lime glass substrates using pulsed laser deposition (PLD) with various process parameters such as laser energy, repetition rate and substrate temperature. It was confirmed that there existed a limited laser energy, i.e. less than 300 mJ, to get phase pure CIGS thin films at room temperature. Particularly, even at room temperature, distinct crystalline CIGS phase was observed in the films. Crystallinity of the films improved with increasing substrate temperature as evidenced by the decrease of FWHM from 0.65° to 0.54°. Slightly Cu-rich surface with Cu2−xSe phase was confirmed to exist by Raman spectra, depending on substrate temperature. Improved electrical properties, i.e., carrier concentration of ∼1018 cm−3 and resistivity of 10−1 Ω cm at higher substrate temperature for the optimal CIGS films are assumed to be induced by the potential contributions from highly crystallized thin films, existence of Cu2−xSe phase and diffusion of Na from substrates to films. 相似文献
6.
p-Sm2S3 films were electrosynthesised from aqueous 0.05 M Sm2O3−0.05 M Na2S2O3−0.25 M tartaric acid bath onto Ti and stainless steel coated substrates. The films were characterized using optical absorption, X-ray diffraction, optical microscopy and chemical analysis. X-ray diffraction showed that films are microcrystalline and free from elemental Sm andS. Optical absorption studies showed that the bandgap is 2.08 eV. (Photo)electrochemical studies of the films were carried out by forming a p-Sm2S3/KI---I2---2KCl/C cell configuration.The current-voltage characteristics were studied in the dark and under white light illumination and at different temperatures. The capacitance-voltage characteristics were studied at 1 kHz frequency. The type of material, junction quality factor, barrier height, flat band potential, etc., were estimated. 相似文献
7.
Nanocrystalline Bi2Se3–Sb2Se3 multilayer thin films were deposited by simple and less investigated successive ionic layer adsorption and reaction (SILAR) method onto glass- and fluorine-doped tin oxide (FTO)-coated glass substrate from aqueous solution. Characterizations such as XRD, surface morphology and optical absorption have been carried out for Bi2Se3–Sb2Se3 thin films onto glass substrates. The films deposited onto FTO-coated glass substrates were used to study photoelectrochemical behaviour in 0.1 M (NaOH–Na2S–S) electrolyte and results are reported. 相似文献
8.
Chinmay Khare Kirill Sliozberg Robert Meyer Alan Savan Wolfgang Schuhmann Alfred Ludwig 《International Journal of Hydrogen Energy》2013
Layered WO3/TiO2 nanostructures, fabricated by magnetron sputtering, demonstrate significantly enhanced photocurrent densities compared to individual TiO2 and WO3 layers. First, a large quantity of compositions having different microstructures and thicknesses were fabricated by a combinatorial approach: diverse WO3 microstructures were obtained by adjusting sputtering pressures and depositing the films in form of wedges; later layers of TiO2 nanocolumns were fabricated thereon by the oblique angle deposition. The obtained photocurrent densities of individual WO3 and TiO2 films show thickness and microstructure dependence. Among individual WO3 layers, porous films exhibit increased photocurrent densities as compared to the dense layer. TiO2 nanocolumns show length-dependent characteristics, where the photocurrent increases with increasing film thickness. However, by combining a WO3-wedge type layer with a layer of TiO2 nanocolumns, PEC properties strikingly improve, by about two orders of magnitude as compared to individual WO3 layers. The highest photocurrent that is measured in the combinatorial library of porous WO3/TiO2 films is as high as 0.11 mA/cm2. Efficient charge-separation and charge carrier transfer processes increase the photoconversion efficiency for such films. 相似文献
9.
Nb2O5 films were prepared successfully by DC reactive sputtering process. The relationships among structural, morphological and electrochromic properties were studied using XRD, AFM, AES and cyclic voltammograms. Results show that the films deposited on heated substrates are composed of columnar TT-Nb2O5 microcrystalline with many grain-to-grain boundaries. These structural characteristics provide films strong electrochemical stability, high Li+ insertion/extraction reversibility and good electrochromic properties. DC reactive sputtered Nb2O5 films are colorless in bleached state and brownish gray in colored state and may be a promising candidate for the application in electrochromic devices. 相似文献
10.
Spinel Li4Ti5O12 thin film anode material for lithium-ion batteries is prepared by pulsed laser deposition. Thin film anodes are deposited at ambient temperature, then annealed at three different temperatures under an argon gas flow and the influence of annealing temperatures on their electrochemical performances is studied. The microstructure and morphology of the films are characterized by XRD, SEM and AFM. Electrochemical properties of the films are evaluated by using galvanostatic discharge/charge tests, cyclic voltammetry and a.c. impedance spectroscopy. The results reveal that all annealed films crystallize and exhibit good cycle performance. The optimum annealing temperature is about 700 °C. The steady-state discharge capacity of the films is about 157 mAh g−1 at a medium discharge/charge current density of 10 μA cm−2. At a considerably higher discharge/charge current density of 60 μA cm−2 (about 3.45 C) the discharge capacity of the films remains steady at a relative high value (146 mAh g−1). The cycleability of the films is excellent. This implies that such films are suitable for electrodes to be used at high discharge/charge current density. 相似文献
11.
A. Yamamoto M. Nakamura A. Seki E. L. Li A. Hashimoto S. Nakamura 《Solar Energy Materials & Solar Cells》2003,75(3-4):451-456
A simple spray method for the preparation of pyrite (FeS2) thin films has been studied using FeSO4 and (NH4)2Sx as precursors for Fe and S, respectively. Aqueous solutions of these precursors are sprayed alternately onto a substrate heated up to 120°C. Although Fe–S compounds including pyrite are formed on the substrate by the spraying, sulfurization of deposited films is needed to convert other phases such as FeS or marcasite into pyrite. A single-phase pyrite film is obtained after the sulfurization in a H2S atmosphere at around 500°C for 30 min. All pyrite films prepared show p-type conduction. They have a carrier concentration (p) in the range 1016–1020 cm−3 and a Hall mobility (μH) in the range 200–1 cm2/V s. The best electrical properties (p=7×1016 cm−3, μH=210 cm2/V s) for a pyrite film prepared here show the excellence of this method. The use of a lower concentration FeSO4 solution is found to enhance grain growth of pyrite crystals and also to improve electrical properties of pyrite films. 相似文献
12.
L.A. Dunyushkina S.V. Smirnov V.M. Kuimov V.P. Gorelov 《International Journal of Hydrogen Energy》2014
CaZr0.9Y0.1O3−δ (CZY) films were fabricated by chemical solution deposition (CSD) from ethanol-based liquid solutions. The films were deposited on single crystals of yttria-stabilized zirconia (YSZ) in (100), (110) and (111) crystallographic orientations. The structural, mechanical and electrical properties of the films have been studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and nanoindentation and impedance spectroscopy methods. XRD and SEM results have shown that the films were polycrystalline. Effect of the substrate orientation on the microstructural, mechanical and electrical properties of CZY films has been examined. The films deposited on (110)-substrates consist of the largest grains; show the highest values of hardness and electrical conductivity. Conductivity of CZY film on (110)-substrates increases with rise in humidity which proves proton transport in the films. 相似文献
13.
M. S. Burdis J. R. Siddle R. A. Batchelor J. M. Gallego 《Solar Energy Materials & Solar Cells》1998,54(1-4)
Thin films of V0.50Ti0.50Ox have been deposited by RF sputtering from metallic targets. Their use as potential counterelectrodes in electrochromic devices has been investigated. It is found that although they are slightly yellow looking in transmission, the films can reversibly store relatively large amounts of charge, whilst showing a reasonably low electrochromic colouration efficiency. The electrochemistry of V0.50Ti0.50Ox is found to be simple, in fact rather similar to that of WO3, making it an almost ideal material to use in such a variable transmission device. 相似文献
14.
Structural and optical properties of e-beam deposited tungsten trioxide (WO3) films in as-deposited and electrochemically coloured states were investigated by spectrophotometric and XRD techniques. These investigations have shown the as-deposited WO3 films to be porous and with small amount of HxWO3 pre-existing in them. The films further facilitate insertion of H+ ions on colouration resulting in tetragonal HxWO3 with a = 4.74Å and c = 3.19Å. 相似文献
15.
Electrochromic behaviour of Nb2O5 thin films with different morphologies obtained by spray pyrolysis
Two different procedures to stabilize the precursor NbCl5 have been applied to obtain Nb2O5 thin films by spray pyrolysis. Depending on the procedure used, determined by the way in which the precursor solution was injected into the air stream of the spray nozzle, niobium oxide thin films with different surface morphologies can be obtained. The structural properties of the Nb2O5 thin films depend on the post-annealing temperature because as-deposited films are amorphous, independently of the synthesis procedure used. The electrochromic behaviour has been estimated for all films, where monochromatic colouration efficiency (at 660 nm) of 25.5 cm2/C and a cathodic charge density close to 24 mC/cm2 were found to give the best results to date for niobium oxide thin films obtained by spray pyrolysis. 相似文献
16.
The reaction of amorphous V2O5 thin films with various organic vapors is investigated using in-situ optical transmission and in-situ Raman spectroscopic measurements. When V2O5 thin films are exposed to vapors of methanol, ethanol, acetone, and isopropanol, changes in the Raman spectrum are observed. These changes are similar to those due to alkali ion intercalation and most pronounced for methanol and ethanol. The optical transmission also increases when the thin films are exposed to methanol and ethanol vapors. Depositing a thin catalyst layer of palladium does not promote the reaction. This result has implications for using this material in hydrogen sensor applications, as extended exposure to organic vapors may not be differentiated from the presence of hydrogen. 相似文献
17.
C. GarzaS. Shaji A. Arato E. Perez Tijerina G. Alan CastilloT.K. Das Roy B. Krishnan 《Solar Energy Materials & Solar Cells》2011,95(8):2001-2005
We report the preparation of copper antimony sulfide (CuSbS2) thin films by heating Sb2S3/Cu multilayer in vacuum. Sb2S3 thin film was prepared from a chemical bath containing SbCl3 and Na2S2O3 salts at room temperature (27 °C) on well cleaned glass substrates. A copper thin film was deposited on Sb2S3 film by thermal evaporation and Sb2S3/Cu layers were subjected to annealing at different conditions. Structure, morphology, optical and electrical properties of the thin films formed by varying Cu layer thickness and heating conditions were analyzed using different characterization techniques. XRD analysis showed that the thin films formed at 300 and 380 °C consist of CuSbS2 with chalcostibite structure. These thin films showed p-type conductivity and the conductivity value increased with increase in copper content. The optical band gap of CuSbS2 was evaluated as nearly 1.5 eV. 相似文献
18.
A. Ennaoui B.R. Sankapal V. Skryshevsky M.Ch. Lux-Steiner 《Solar Energy Materials & Solar Cells》2006,90(10):1533-1541
Simple soft-solution method has been developed to synthesize films and powders of TiO2 and mixed TiO2–SiO2 at relatively low temperatures. This method is simple and inexpensive. Furthermore, reactor can be designed for large-scale applications as well as to produce large quantities of composite powders in a single step. For the preparation of TiO2, we used aqueous acidic medium containing TiOSO4 and H2O2, which results in a peroxo-titanium precursor while colloidal SiO2 has been added to the precursor for the formation of TiO2–SiO2. Post annealing at 500 °C is necessary to have anatase structure. Resulting films and powders were characterized by different techniques. TiO2 (anatase) phase with (1 0 1) preferred orientation has been obtained. Also in TiO2–SiO2 mixed films and powders, TiO2 (anatase) phase was found. Fourier transform infrared spectroscopy (FTIR) results for TiO2 and mixed TiO2–SiO2 films have been presented and discussed. The method developed in this paper allowed obtaining compact and homogeneous TiO2 films. These compact films are highly photoactive when TiO2 is used as photo anode in an photoelectrochemical cell. Nanoporous morphology is obtained when SiO2 colloids are added into the solution. 相似文献
19.
Spray pyrolysis is a low-cost method of depositing thin films and is economically more attractive than other methods that have been used to produce stable CuInS2 thin films. The electrical, optical and structural properties of the films, as prepared, are presented together with their evolution and with a variation of some fabrication parameters which are the fabrication temperature TS, and the ionic ratio R = Cu : In : S in the solution. 相似文献
20.
Jing Du Yanfeng Gao Hongjie LuoZongtao Zhang Litao Kang Zhang Chen 《Solar Energy Materials & Solar Cells》2011,95(7):1604-1609
VO2-ZrV2O7 composite films were prepared on silica glass substrates by polymer-assisted deposition using a V-Zr-O solution. The coexistence of ZrV2O7 and VO2 was confirmed by Raman spectroscopy, glance angle X-ray diffraction, and X-ray photoelectron spectroscopy. The composite films with similar thickness of about 95 nm showed decreased particle sizes and significantly enhanced luminous transmittances (from 32.3% at Zr/V=0 to 53.4% at Zr/V=0.12) with increasing Zr/V rations. The enhancement in the luminous transmittance was ascribed to the absorption-edge changes in the composite films. This feature benefits the application of VO2 to smart windows. 相似文献