| CIS-based solar cells is one of the most promising thin film solar cells, but this type of solar cells has bottleneck in large scale industrialization for that the preparation technologies of CIS-based absorption layer are very complicated and less of controllable. The research of CIS-based powders can cast new insights on the preparation of CIS-based thin films, which are hopeful for improving the technics and reducing the cost of absorption layer preparation substantially. For the problems in current preparation reseanch of CIS-based powders, this thesis is aimed for investigation of preparation technology of low cost and high quality CIS-based powders, and the technology can be easily industrialized. In this thesis, CIS-based powders were prepared by refluxing reaction route using metal halides and Se/S powder as starting materials. The main works and results obtained can be summarized as follows:(1) CuInSe2 powders were prepared by refluxing reaction with rapid heat treatment using ethylenediamine as the solvent. The effects of technology conditions on the products were investigated, and the reaction mechanism was analyzed. The results show that the products of refluxing reaction are binary diselenide of Cu and In, from which single phase chalcopyrite CuInSe2 can be made by heat treatment. The atoms ratio of prepared powders is almost consistent with the stoichiometry of CuInSe2. Rising the temperature or increasing the time of heat treatment are helpful for the complete formation of CuInSe2 phase and improvement of crystallinity, but prolonging the time of heat treatment has negative effect on the morphology of the products,600℃/30 min is the proper condition of the heat treatment in preparing CuInSe2 powders.(2) CuInSe2 powders were directly prepared by refluxing reaction using triethylenetetramine as the solvent. The factors such as reaction time, temperature potentially affecting the expected final product were investigated, and a possible formation mechanism was also put forward and briefly discussed. The results showed that CuInSe2 powders with single phase, regular morphology and stoichiometric composition can be synthesized in triethylenetetramine, and the reaction time was considerably reduced. Moreover, the optimum technical conditions were obtained at 200℃for 1～2 h. With the increasing of the reaction temperature, the products can be rapidly synthesized with well crystallinity. While the same technical conditions were used to synthesize CuInS2, the as-synthesized sample contained impurities. When triethylenetetramine-glycol was used as the solvent, the pure phase of CuInS2 can be obtained. Compared to CuInSe2 powders, CuInS2 can be easily synthesized with the fine and even particles.(3) With a mixed solvent of triethylenetetramine-glycol, CuIn(SxSe1-x)2 powders were synthesized by refluxing reaction method. The influence of S content on the optical and electrical properties was further studied. The characterizations showed that the synthesized chalcopyrite CuIn(SxSe1-x)2 had single phase, regular morphology which is closed to spheres with smaller size, and stoichiometric composition closely followed originally mixing ratio. The incorporation of S has obvious effect on band-gap elevation of CIS materials. With the increasing of S content, the carrier concentration of CuIn(SxSe1-x)2 was gradually reduced with the increasing of mobility and resistivity. While the value of S/(S+Se) maintained at 0～0.6, CuIn(SxSe1-x)2 showed p-doped semiconductor, and the electrocal properties made them promising candidates as absorber materials for photovoltaic applications. |
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