具有特定裸露晶面金属卤化物钙钛矿单晶材料的可控制备及其“晶面间光生电荷空间分离”机理研究

The performance improvement of perovskite solar cell strongly depends on precise controlling the quality of perovskite materials and profound understanding of the separation and transport mechanism of photogenerated charges within it. This proposal will carry out the research firstly on the basis of controllable synthesis of metal halide perovskite single crystals with specific exposed facets, and systematically investigate the optical/electrical heterogeneity of different exposed facets, and reveal the dissimilarity in the generation, separation, diffusion and recombination behaviour of photogenerated charges, build the comprehensive correlation between them and screen out the optimal facets for fabricating solar cell; Moreover, on the basis of band structure and precise position of band edges of facets, further propose and validate the possibility of forming the “facet heterojunction” between adjacent facets, and explore the mechanism of “spatial separation of photogenerated charges between different facets” based on metal halide perovskite materials, and eventually build highly-efficient and stable perovskite materials and solar cells based on the facet-tailoring technique, and provide the theoretical evidence and experimental basis for constructing highly-efficient and stable perovskite materials and optoelectronic devices.

钙钛矿太阳电池性能提升取决于钙钛矿材料质量的精确调控及其内部光生电荷分离和输运机理的深刻理解。本项目拟在具有特定裸露晶面钙钛矿单晶材料的可控制备基础上，系统地研究各裸露晶面的光学/电学性质差异，揭示光生电荷在各晶面上产生、分离、输运和复合行为及其差异性，建立各晶面光生电荷分离和输运能力差异与光电性能异质性的广泛关联性，筛选出最适合制备太阳电池器件的晶面；根据钙钛矿各晶面能带结构及导带底和价带顶的精确位置，提出并验证相邻晶面间构成“晶面异质结”的可能性，探索以金属卤化物钙钛矿材料为基础的“晶面间光生电荷空间分离”机制，最终构建基于晶面调控技术的高效、稳定的钙钛矿材料和太阳电池器件，为制备高效、稳定的新型钙钛矿材料和光电器件提供一些可供参考的实验基础和理论依据。

钙钛矿太阳电池性能的提升取决于钙钛矿材料质量的精确调控及其内部光生电荷分离和输运机理的深刻理解。本项目基于表面活性剂和两步溶液法获得具有特定裸露晶面钙钛矿单晶材料（微米板，量子点，多晶薄膜等形态），采用机械可控裂结和微纳液态金属电极等原位分析方法，结合理论计算指导，系统地研究裸露晶面的光电学性质差异，尝试揭示光生电荷在各晶面上产生、分离、输运和复合行为及其差异性；采用不同晶面间光生电压等测试验证相邻晶面间构成“晶面异质结”的可能性，探索了金属卤化物钙钛矿材料为基础的“晶面间光生电荷空间分离”机制，受限于有限的晶面种类或晶面质量问题，暂无定论。