强磁场下有机-无机杂化钙钛矿晶体生长及光电性能研究

Due to the defects and poor stability of the organic-inorganic hybrid perovskite polycrystalline films, the application and service life are limited. While the perovskite single crystals with low defects and no grain boundaries show relatively good stability. This project is intended to prepare high quality perovskite single crystals under high magnetic field. Aiming at establish the process methods for preparing organic-inorganic hybrid perovskite single crystals under high magnetic field, change the material growth mode and reduce crystal defects. Uncover the conditions and mechanism of the influence of high magnetic field on the growth orientation of perovskite materials. Reveal the growth mode of single crystal under magnetic field. Optimize crystal nucleation and growth process, and improve crystal quality. Clarify the universal law of crystal growth of organic-inorganic hybrid perovskite materials under high magnetic field. Provide a theoretical basis for obtaining high quality perovskite single crystal materials under high magnetic field. Understand the influence mechanism of photoelectric properties, stability and microstructure by systemic photoelectric measurements. Find the intrinsic factor that affects the optoelectronic properties and stability of organic-inorganic hybrid perovskite crystals, and provide ideas for improving the service life of organic-inorganic hybrid perovskite optoelectronic devices.

由于有机-无机杂化钙钛矿多晶薄膜的缺陷较多、稳定性较差，限制了其应用范围和使用寿命，而无晶界、低缺陷的钙钛矿单晶则展现出了较好的稳定性。本项目拟在强磁场下制备高质量的有机-无机杂化钙钛矿单晶。建立适用于强磁场下制备有机-无机杂化钙钛矿单晶的工艺方法，达到改变材料生长模式、优化晶体缺陷的效果。明确强磁场对于钙钛矿材料生长取向的影响条件及机理，揭示磁场下单晶的生长模式、优化晶体成核及生长过程、提高晶体质量，阐明强磁场下有机-无机杂化钙钛矿材料的普适性晶体生长规律，为强磁场下获得高质量的钙钛矿单晶材料提供理论依据。通过系统性光电性能测试，从强磁场诱导晶体生长过程的角度揭示光电性能、稳定性和微结构的影响机制，明确影响有机-无机杂化钙钛矿晶体光电性能，尤其是稳定性的内在因素，为提高有机-无机杂化钙钛矿光电器件的使用寿命提供思路。

强磁场是一种可用来控制分子排列和取向以及生长模式，调控材料结构和性能、降低缺陷的干净、普适性手段。MAPbI3、MAPbBr3等有机-无机杂化钙钛矿材料由于其优异的光电性能已经被广泛应用于太阳电池、激光、发光二极管、光敏剂以及光电探测器等领域。但钙钛矿薄膜材料的缺陷较多、稳定性较差，限制了器件的性能和寿命，而无晶界、低缺陷的钙钛矿单晶则展现出了较好的稳定性。本项目旨在强磁场下制备高质量的钙钛矿单晶。.本项目在国家自然科学基金青年科学基金项目的资助下实现了原定目标，在强磁场下分别使用反溶剂扩散法和逆温溶液生长法得到了MAPbI3和MAPbBr3两种有机-无机杂化钙钛矿单晶，并重点研究了强磁场下逆温溶液生长法，从而得到了尺寸超过5 mm的高质量MAPbI3和MAPbBr3单晶。通过XRD、SCLC以及TPL等测量表征手段表明，强磁场下制备得到的MAPbI3单晶载流子迁移率可达55.72 cm2V-1s-1，陷阱密度为1.57 × 1010 cm-3，载流子扩散长度为6.84 μm，均达到了预期研究目标。本项目扩充了强磁场下有机-无机杂化材料的制备方法，探讨了强磁场下有机-无机杂化晶体材料的生长机理，探索了影响有机-无机杂化钙钛矿晶体及器件稳定性的内在因素，为基于有机-无机杂化钙钛矿单晶的光电器件实用化提供了详实的科学依据。