大尺寸二维Bi掺杂钙钛矿的液相-气相置换联用法制备及其光电性能研究

Organic-inorganic hybrid perovskites have been arousing great attention, owing to their remarkable optoelectronic attributes. While the stability and toxicity restrict their further development. Two-dimensional layered perovskites exhibit improved stability, and Bi-doped perovskites could effectively reduce the toxicity. But it is extremely hard to achieve large-sized Bi-doped perovskite nanoflakes via traditional solution synthesis, thus hindering the investigation of photophysical properties on nanoscale and further improvement on optoelectronic performance. In this project, we will fabricate a series of large-sized two-dimensional Bi-doped perovskite (PEA)2Bi2x/3Pb1-xX4 nanoflakes by liquid phase-vapor phase substitution combined method. We aim to achieve Bi-doped perovskites with lateral size of ～10 μm, thickness of ～4 nm and tunable Bi composition, and further elucidate their formation mechanism through investigating the correlation between the synthesis factors and the microstructure, composition and thickness of the obtained materials. Furthermore, the influence of Bi composition, thickness and photophysical properties on the optoelectronic performance of photodetector will be revealed. On the basis of above, we will accurately manipulate the microstructure and photophysical properties of the materials to obtain highly efficient photodetectors. We believe this project will provide theoretical basis and technology support for the development of two-dimensional Bi-doped perovskite and their optoelectronic application.

有机-无机杂化钙钛矿因其优异的光电性质而广受关注，但稳定性和毒性制约了该材料的发展。二维层状钙钛矿表现出改善的稳定性，Bi掺杂钙钛矿能有效降低其毒性。但传统的液相法难以制备大尺寸Bi掺杂钙钛矿超薄片，进而限制了材料纳米尺度上光物理性质的研究及光电性能的改善。本项目拟采用液相-气相置换联用法构建大尺寸二维层状Bi掺杂钙钛矿(PEA)2Bi2x/3Pb1-xX4超薄片，通过研究制备条件对产物的影响，明确关键制备因素与钙钛矿尺寸、厚度和Bi组分的内在关联，实现～10微米尺寸、～4纳米厚度和Bi组分可控的钙钛矿的制备，并探索其形成机理；构筑Bi掺杂钙钛矿超薄片光电探测器，通过对单个超薄片的微观结构和光物理性质的表征和测试，研究Bi组分、材料厚度、光电性质对器件性能的影响规律，精确调控材料的结构，以期获得高效、稳定的光电探测器，为二维Bi掺杂钙钛矿的发展和光电应用提供理论依据和技术支持。

有机-无机杂化钙钛矿因其优异的光电性质而在光电领域广受关注。然而，要实现杂化钙钛矿的商业化应用，必须解决其稳定性和毒性这两大问题。这两点是近年来钙钛矿领域的研究热点，也是本课题的主要研究对象。本项目主要是通过钙钛矿组分的设计和电子能带结构的调控来开发稳定的无铅杂化铋卤钙钛矿体系：采用混合相有机胺阳离子和有机双胺阳离子等模板剂来导向量子阱型铋卤钙钛矿结构的形成，实现无机铋卤钙钛矿框架结构和有机阳离子空间构型的精确调控；通过理论计算研究其电子能带结构，结合实验研究分析其光物理性质，揭示了量子阱结构所导致的特殊激子性质及载流子传输性质；最后以杂化铋溴钙钛矿为载体材料构建X射线探测器，研究了其探测性能，揭示了晶体结构与光、电学性质和探测性能间的内在联系。在此项目的支持下，我们还设计制备了一系列基于双官能团阳离子和共轭甲基化二胺阳离子的低维铅卤钙钛矿，并开展了其结构与性能间的构效关系研究，揭示了其内在机制。