钙钛矿(CH3NH3)PbI3单晶薄膜弯曲过程中晶体结构演变及其对光电性能的影响机理

钙钛矿单晶薄膜具有优异的载流子传输性能、低的缺陷态浓度、良好的可弯曲特性及低廉的制备成本，是用于高性能柔性光电器件的潜在材料。其中，单晶薄膜的弯曲特性、弯曲对晶体结构及其稳定性的影响、以及由于弯曲产生的晶格应力对电荷传输性质的影响机理是实现高性能钙钛矿单晶柔性光电器件必须要解决的关键科学问题。本项目围绕上述问题，以典型钙钛矿(CH3NH3)PbI3单晶薄膜为研究对象，研究单晶薄膜弯曲性能和厚度的关系，进而分析其弯曲模型；研究原位弯曲过程中单晶薄膜的晶体结构演变、载流子动力学及缺陷态的变化。此外，通过在单晶薄膜上制备光探测器和太阳电池，同步研究单晶薄膜器件处于不同弯曲曲率半径时的光电转换效率及其稳定性。结合以上研究内容，建立单晶薄膜弯曲特性-晶体结构-光电性能之间的内在联系，揭示该单晶薄膜在弯曲过程中晶体结构演变及其光电性能转变机理。该项目将为设计高性能柔性钙钛矿单晶光电器件提供有效指导。

Single-crystalline perovskite membrane (SCPM) is a potential material for the application of high-performance flexible photoelectronic devices, due to its excellent carrier transport property, low defect state concentration, good bendability and low fabrication cost. During this process, the key scientific issues that must be solved to realize its high performance flexible photoelectronic devices, such as the bending characteristics, the effect of bending on crystal structure and its stability, and the effect of lattice strain on the charge carrier dynamics during bending process. In this project, we choose typical (CH3NH3)PbI3 SCPMs as the research object to study the relationship between bending property and thickness, and the relative bending model. We will further study the evolution of crystal structure, carrier dynamics and the change of defect state during bending through in situ characterizations. In addition, by preparing photodetectors and solar cells based on the SCPMs, the photoelectric conversion efficiency and its stability will be studied simultaneously when the devices are in different bending radii of curvature. Combining all above results, the intrinsic connection among bending characteristics, crystal structure and photoelectric properties will be established. During the bending process, the mechanism of structural and photoelectronic evolution for single-crystalline membrane will also be revealed. The achievements in this project will provide constructive ideas for the design of high-performance flexible perovskite single crystal photoelectronic devices.