铜锌锡硫纳米结构的制备、相变与光电性能研究

发布时间：2018-08-27 11:52

【摘要】：铜锌锡硫(Cu_2ZnSnS_4, CZTS)作为吸光层材料在下一代太阳能电池应用中具有良好的发展潜力,该材料具有合适的禁带宽度(～1.5eV),在可见光区有较高的吸光系数(104cm-1),具有相变特性,其组成元素在地壳储量丰富、无毒、环境友好。但是CZTS和相关多元化合物半导体纳米结构的制备通常采用高温胶体溶液法,该方法涉及使用有机溶剂或长碳链有机分子,价格昂贵且对环境有污染。因此,发展绿色方法合成CZTS纳米结构并实现其形貌和物相的调控具有重要意义。本论文中,我们发展一种绿色水热法制备CZTS和Cu_2SnS_3(CTS)纳米结构,并系统研究其光学和光电性能。主要结果如下:(1)首次报道通过一种“自上而下”的方式制备出六方纤锌矿结构CZTS纳米晶,该方法未使用任何有机溶剂。CZTS纳米晶是通过Cu_2O纳米方块与Sn-MCC配合物水溶液及Zn~(2+)离子水溶液反应生成的,纳米晶的尺寸为5±2 nm。研究表明,形成过程经历了 Cu_2O纳米方块→Cu_2-xS纳米盒子→CZTS纳米盒子→CZTS纳米晶的演变过程。CZTS纳米盒子的形成是由于“柯肯达尔效应”作用的结果,而CZTS纳米晶的形成是酸刻蚀的效果。生长溶液pH值对所生成的CZTS的晶相具有重要影响,中性溶液有利于生成六方纤锌矿结构CZTS,碱性溶液有利于生成四方闪锌矿结构CZTS。所合成的六方纤锌矿结构CZTS纳米晶具有显著的光致发光效应和光电效应,在低成本太阳能电池方面具有良好的应用前景。(2)通过Cu_2O纳米方块与Sn-MCC配合物水溶液反应首次制备了六方相CTS纳米盒子,其形成过程经历了 Cu_2O→Cu_2-xS→CuS→CTS。纳米盒子的形成是由于“柯肯达尔效应”作用的结果。通过退火处理,六方相CTS纳米盒子会转变成四方相CTS纳米盒子。光学性能研究表明,六方相CTS纳米盒子和四方相CTS纳米盒子的禁带宽度分别为1.4和1.2 eV。我们深入研究了 CTS纳米盒子的光电化学特性,表明其在光解水制氢方面具有良好的发展。
[Abstract]:Copper, zinc, tin and sulfur (Cu_2ZnSnS_4, CZTS) have good development potential in the application of next generation solar cells as absorbent layer materials. This material has suitable band gap (1.5 EV), high absorption coefficient (104cm-1) in visible region, and phase transition characteristic. Its components are abundant in the crust, non-toxic and environmentally friendly. However, the preparation of semiconductor nanostructures of CZTS and related polycompounds is usually carried out by high-temperature colloidal solution method, which involves the use of organic solvents or long-chain organic molecules, which is expensive and pollutes the environment. Therefore, it is of great significance to develop green methods to synthesize CZTS nanostructures and control their morphology and phase. In this thesis, we developed a green hydrothermal method to prepare CZTS and Cu_2SnS_3 (CTS) nanostructures, and systematically studied their optical and optical properties. The main results are as follows: (1) Hexagonal wurtzite CZTS nanocrystals were prepared by a top-down method for the first time. The method does not use any organic solvent. CZTS nanocrystalline is formed by the reaction of Cu_2O nanometers with Sn-MCC complex aqueous solution and Zn~ (2) ion aqueous solution. The size of nanocrystalline is 5 卤2 nm.. The results show that the formation process of CZTS nanocrystalline CZTS is due to the effect of "Kokkendal effect", and the formation process has experienced the evolution of CZTS nanocrystalline crystal. The formation of CZTS nanocrystals is the effect of acid etching. The pH value of the growth solution has an important influence on the crystal phase of the formed CZTS, and the neutral solution is favorable to the formation of hexagonal wurtzite structure CZTS, alkaline solution and the tetragonal sphalerite structure CZTS.. The synthesized hexagonal wurtzite CZTS nanocrystals have significant photoluminescence and photoelectric effects. (2) the hexagonal CTS nanobox was prepared by the reaction of Cu_2O nanobircle with Sn-MCC complex aqueous solution for the first time, and its formation process experienced Cu_2O Cu_2-xS Cu_2-xS CuS CTS. (2) Hexagonal CTS nanobox was prepared by the reaction of Cu_2O nanobircle with Sn-MCC complex aqueous solution for the first time in the field of low-cost solar cells. The nanobox was formed as a result of the Kokkendal effect. After annealing, the hexagonal CTS nanobox will be transformed into tetragonal CTS nanobox. The optical properties show that the band gap of hexagonal CTS nanobox and tetragonal CTS nano-box are 1.4 and 1.2 eV., respectively. The photochemical properties of CTS nanobox have been studied in detail. It is shown that CTS nanobox has a good development in the production of hydrogen by photolysis of water.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN304;TB383.1

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