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Filmes de disseleneto de cobre e índio depositados por spray-pirólise
摘要： Cu1-xInxSe2 (0.45≤x≤0.80) films were deposited on glass substrate by spray pyrolysis technique, for use as absorbing layer of photovoltaic cells. The structural, morphological, optical and electrical properties of the films were analyzed according to the variation of the stoichiometry used. The analysis by X-ray diffraction showed that the most intense peaks were of orientation (204/220) and the films have the phases CuSe, CuSe2 and CuInSe2. The films showed uniform surface without cracks independently of the stoichiometry used. In the electrical characterization, the deposited films showed activation energy of the electrical conduction process with average value of 0.74 eV and typical behavior for semiconductors. The optical characterization was performed at the wavelength gap of 350 to 1100 nm, and the films showed absorption coefficient on the order of 103 cm-1 in the wavelength of 550 nm and optical band gap of 1.4 eV. The results indicated that the most suitable condition for deposition of films for their application as absorbing layer had as substrate temperature 400 °C, a solution flow rate of 1 mL/min, deposition time of 10 min and stoichiometry of Cu0.2In0.8Se2, thus obtaining films without cracks, with large absorption coefficient of 6.8x103 cm-1 for the wavelength of 550 nm, thickness of approximately 2.5 μm and electrical resistivity of 0.13 k .m at room temperature.
关键词： absorbing layer,copper indium diselenide,spray-pyrolysis
更新于2025-09-04 15:30:14
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<i>In situ</i> topotactic fabrication of direct Z-scheme 2D/2D ZnO/Zn <sub/>x</sub> Cd <sub/>1?x</sub> S single crystal nanosheet heterojunction for efficient photocatalytic water splitting
摘要： Direct Z-scheme heterojunction can effectively enhance the photocatalytic activity due to its low carrier recombination rate and high redox ability. In this study, a 2D/2D ZnO/ZnxCd1?xS single crystal nanosheet heterojunction is synthesized in situ by topotactic sulfurization/oxidization pyrolysis of Zn/Cd/Al layer double hydroxides (LDHs). Its unique structure provides not only numerous intimate interfaces but also a direct Z-scheme junction. The in situ topotactic fabrication of ZnO by the oxidation process causes some Zn ions to dissolve out from the Zn0.67Cd0.33S solid solution nanosheets with increase in annealing temperature and time. The longer the time for oxidation, the more ZnO is obtained. The formation of ZnO yields 2D/2D ZnO/ZnxCd1?xS single crystal nanosheet heterojunction, which increases the visible light absorption and boosts the separation of photogenerated carriers. The ZnO/ZnxCd1?xS-4 single crystal nanosheet heterojunction presents the highest photocatalytic activity under visible light irradiation (38.93 mmol h?1 g?1), which is nearly 16.93 times higher than that of Zn0.67Cd0.33S-300, and an external quantum efficiency of 40.97% at λ = 420 nm. The proposed synthetic route for the construction of 2D/2D ZnO/ZnxCd1?xS single crystal nanosheet provides a direct Z-scheme structure with highly efficient photocatalytic hydrogen evolution activity.
关键词： 2D/2D ZnO/ZnxCd1?xS,photocatalytic water splitting,Zn/Cd/Al layer double hydroxides,Direct Z-scheme heterojunction,topotactic sulfurization/oxidization pyrolysis
更新于2025-09-04 15:30:14