动态热载荷作用下钙钛矿太阳能电池界面疲劳特性研究

Great breakthroughs of the efficiency of organic-inorganic hybrid perovskite photovoltaic cells have been achieved, while their commercial application is severely restricted by the stability. The problem of interface fatigue caused by interface stress mismatch between perovskite layer and substrate in perovskite photovoltaic devices under long-term dynamic thermal load will be studied in this project. The cyclic stress response behavior of perovskite monocrystalline materials under the condition of thermal mechanical fatigue will be analyzed via variable temperature X-ray diffraction technique, and the response law between intrinsic structures and strain characteristics of perovskite monocrystalline materials will be established. Combined with high resolution scanning transmission electron microscope and energy dispersive X-ray mapping analysis, propagation of the fatigue crack at the interface of perovskite device under cyclic thermal loading will be monitored, and interface energy dissipation model based on perovskite photovoltaic devices will be established. Based on above research, the theoretical basis and practical experience for the preparation and application of perovskite photovoltaic modules with high mechanical stability will be provided in this project with a unified rule between the interface strain characteristics and device performance degradation mechanism by integrating material selection and device structure design to optimize the interface stress-strain characteristics.

有机无机杂化钙钛矿光伏电池的效率已经取得巨大突破，稳定性已经成为制约钙钛矿电池商业化发展的关键短板。项目针对钙钛矿光伏器件在长时间动态热载荷作用下，由于钙钛矿层与基底之间应力失配导致的界面疲劳问题展开研究。采用变温X射线衍射技术分析钙钛矿单晶材料在热机械疲劳条件下的循环应力响应行为，确定钙钛矿材料的本征结构与应变特性之间的响应规律；结合高分辨扫描透射电子显微镜和能量色散X射线光谱扫描分析技术，监测钙钛矿器件界面在循环热加载过程中的疲劳裂纹扩展，建立钙钛矿基光伏器件界面能量耗散模型；综合材料的选择和器件结构设计，优化界面应力应变特性，建立界面应变特性与器件性能退化之间的统一规律，旨在为高机械稳定性钙钛矿光伏模组的制备与应用提供理论基础和实践经验。

有机-无机杂化钙钛矿材料种类多、制备方法简单、结构可调性强，具有优异的光学和电学特性，在太阳能电池、发光二极管、光电探测器、激光器等领域都具有广泛的应用。总体来看，这些器件都可归纳为一类金属或半导体材料薄膜-基底的多层级结构器件。在前期大量的研究中，基于光照、水氧等外部因素引起的器件性能退化得到有效解决，对机械应力引起稳定性下降的研究相对较少。本项目专注于研究多层结构钙钛矿器件的界面应变机制，探索界面材料对器件性能及稳定性的影响规律。通过本项目的研究，取得了如下成果：1）通过精巧的材料选择和器件设计，对多层结构钙钛矿器件的界面应变机制开展了研究，为高稳定性钙钛矿多层结构器件的制备提供重要指导；2）基于此机理，开发了基于钙钛矿/石墨烯复合功能薄膜新型致动器，实现对复合薄膜的可编程控制，为后续的可编程柔性机器人提供了新的思路；3）开展了高效全钙钛矿基白色PLEDs研究，针对其中间连接层的界面修饰以及机械性能对比研究，有效地抑制了卤化物迁移，器件实现了创纪录的8.5%的EQE，为高效串联白色钙钛矿发光二极管的应用铺平了道路。