聚集诱导发光液晶分子工程构建准二维Ruddlesden-Popper钙钛矿及其光伏电池

实现垂直择优取向生长、提高微观结构有序性、增强层间电荷和能量传输及相互作用是提高准二维Ruddlesden-Popper (Q-2DRP)钙钛矿太阳电池效率和稳定性的关键。本项目提出设计合成具有聚集诱导发光性质的共轭液晶性有机胺，构筑Q-2DRP钙钛矿及其太阳电池。利用有机胺的液晶性，研究其取向有序排列方式对Q-2DRP钙钛矿薄膜结晶生长的影响，实现分子水平上精确调控Q-2DRP钙钛矿结晶生长取向和微观结构有序性，通过液晶驱动，诱导择优垂直取向生长，提高微观结构有序性，构建通畅载流子传输通道。利用有机胺的半导体性和聚集诱导发光性质，有效调控有机胺阳离子层与无机钙钛矿层之间的能级排列，实现高效敏化机制，增强层间能量和电荷传输，降低载流子传输势垒，提高光吸收效率。利用有机胺的强超分子相互作用，提高稳定性。本项目为设计开发新型功能性有机胺阳离子，实现高效稳定Q-2DRP钙钛矿太阳电池提供新策略。

Quasi two-dimensional Ruddlesden-Popper (Q-2DRP) perovskites have attracted much attention for application in perovskite solar cells (PSCs) due to their improved stability. However, the power conversion efficiencies (PCEs) based on Q-2DRP perovskites have far lagged behind those PSCs based on three-dimensional (3D) perovskites. To fabricate highly efficient and stable Q-2DRP PSCs, vertical alignment of the inorganic slabs, ordered microstructure and enhanced the charge and energy transfer between inorganic/organic layers and strengthened interlayer interaction, should be achieved. To address these issues, in this project, a kind of novel bulky organic cations with π-conjugated mesogens and aggregation-induced emission properties will be designed and synthesized to prepare the Q-2DRP perovskites. Benefiting from the ordered orientation behavior of conjugated mesogens, precise control of the crystal growth orientation and microstructure orderness of Q-2DRP perovskite films at the molecular level can be realized. The influence of different packing arrangements of π-conjugated mesogens on the crystal growth of Q-2DRP perovskite films will be investigated. Driven by the π-conjugated mesogens, preferred vertical orientation growth and improved microstructure orderness of Q-2DRP perovskite films can be achieved to facilitate the transportation of charge carriers. By virtue of the semiconductor characteristics and aggregation-induced emission properties of π-conjugated mesogens, the band level alignment between inorganic slabs and organic layers can be well controlled and the highly efficient sensitization process can be realized. The energy and charge transfer will be promoted between organic/inorganic layers, thereby, reducing the charge transfer barrier and improving the light absorption efficiency. Moreover, the strong supramolecular interaction of π-conjugated mesogens will efficiently enhance the interlayer interaction of Q-2DRP perovskites, eventually further improving the stability. The project will provide a new and promising strategy to design and develop novel functionalized bulky organic cations for highly efficient and stable Q-2DRP PSCs.