气相蒸镀钙钛矿晶体的生长机理研究及晶体形貌对器件光电性能的影响

In recently years, organohalide perovskite solar cells have exhibited a significant leap in efficiency from 3.8% in 2009 to 21% till now. However, the mechanism of crystal growth of perovskite has not completely investigated yet, and the methodology of controlling the crystal growth is merely limited to solution-processing. The perovskite crystals disorderly grow during solution process which will lead to the crystal uniformity and film continuity uncontrolled. Therefore, this project will be adopting the dual-source vapour deposition system and integrating theoretical models with experimental analysis, to build a controlling system as well as to reveal the mechanism of perovskite crystal growth under vapour deposition. Moreover, the correlations between the crystal size of perovskite and the photoelectric properties of perovskite films, such as conductivity, absorption and so on will be studied, in order to reduce the defects and improve the photoelectric properties of perovskite films. To explore the possibility of further improving the device efficiency, the correlations among the crystal size of perovskite, the photoelectric properties of perovskite films and the device performance will be studied systematically. The implementation of this project has a significant impact on the understanding of the working principle of perovskite solar cells, as well as it will provide necessary guarantees for the industrialization of perovskite solar cells.

近年来，基于有机金属卤化物钙钛矿材料的太阳能电池迅速发展，电池的光电转化效率已从2009年的3.8%突破至目前的21%。然而，有关此类钙钛矿晶体生长机理的探索尚未完善，调控晶体生长形貌的方法也仅限于溶液法，溶液法中晶粒的无序生长易导致晶粒均匀性、薄膜连续性的不可控。因此，本项目拟改造双源共蒸法，综合理论模型与实验分析结果，建立钙钛矿晶体生长的控制系统，揭示钙钛矿晶体在气相蒸镀条件下的生长机理；分析晶体尺寸与薄膜物性如导电性、吸光性等之间的关系，降低薄膜缺陷，提高薄膜的光电性质；揭示钙钛矿晶体尺寸、薄膜物性与器件性能三者间的关联系统，探索钙钛矿晶体形貌优化对进一步提高器件效率的可能性。本项目的实施对深入理解钙钛矿太阳能电池的工作机理具有重要意义，为钙钛矿太阳能电池的工业化生产提供了必要保障。

近年来，基于有机金属卤化物钙钛矿材料的太阳能电池迅速发展，电池的光电转化效率已从2009年的3.8%突破至目前的25%。然而，有关此类钙钛矿晶体生长机理的探索尚未完善，调控晶体生长形貌的方法也仅限于溶液法，溶液法中晶粒的无序生长易导致晶粒均匀性、薄膜连续性的不可控。本项目通过气相真空蒸镀法制备钙钛矿晶体以及太阳能电池，研究了气相蒸镀条件下的晶体生长机理以及器件性能。本项目首先基于晶体成核理论基础，在理想真空蒸镀条件下建立了晶体生长的控制模型，再以此模型为基础，通过对钙钛矿材料固有特征的分析，建立关于钙钛矿晶体生长的理论模型。基于该理论模型，本项目改造了双源共蒸法，建立钙钛矿晶体生长的控制系统，结合实验结果进一步优化了理论模型，并对比了蒸镀法与溶液法调控钙钛矿晶体的机理差异。制备了具有不同晶粒尺寸的钙钛矿薄膜，分析晶体尺寸与薄膜物性如导电性、吸光性、光致发光效率等之间的关系，从而降低薄膜缺陷，提高薄膜的光电性质。最后本项目基于不同的钙钛矿构建了太阳能电池器件，建立了钙钛矿晶粒尺寸、薄膜物性及钙钛矿电池性能三者之间的关联系统。本项目的实施对深入理解钙钛矿太阳能电池的工作机理具有重要意义，为钙钛矿太阳能电池的工业化生产提供了必要保障。