铅卤钙钛矿材料光辐照不稳定性的机理研究

Lead trihalide perovskites are promising materials for high-performance photvoltaic and light-emitting devices owing to their excellent optical properties. However, the photo-instability of this class of materials greatly hinders their applications. So far the mechanism of the photo-instability is not clear. In this project we are dedicated to understand the mechanism from the pointview of carrier recombination by studying the influences of trap states. Focusing the key issues of the trap identification and carrier recombination dynamics under light soaking, we will investigate the solution-processed perovskites via evaluating the defects, determining the photo-induced traps as well as their parameters, figuring out the recombination dynamics of photocarriers, etc, based on our proposed new concept of trap discrimination and controllable photo-passivation of trap states. We expect to unravel the atomic origin of trap states, to clarify the recombination dynamics, and to understand the photo-instability mechanism of perovskites. It is believed that the studies of this project will enrich the fundamental physics of carrier recombination in peovskites, and facilitate the design and fabrication of materials and devices based on perovskites. It may have great scientific significance and potential applications in future optoelectronic devices.

铅卤钙钛矿材料同时具有优异的光伏和发光性能，在高性能太阳能电池和发光器件方面均极具应用前景。但钙钛矿在光辐照下的不稳定性是其应用的一大制约，目前对其机理研究还不够深入。本项目拟从陷阱态的影响入手，从光生载流子的复合角度理解其物理机制。我们将以溶液法制备的钙钛矿为研究对象，针对陷阱态指认和光辐照下载流子复合机理这两个关键科学问题，采用对陷阱态进行有效区分和可控光钝化等新思路，通过对钙钛矿缺陷情况、光诱生陷阱态、陷阱态基本属性及其参与的复合过程等方面进行深入研究，揭示陷阱态的起源，阐明光生载流子复合机制，最终理解光辐照下钙钛矿不稳定性的机理。本项目研究将丰富铅卤钙钛矿材料的知识体系，为钙钛矿材料和光电子器件的设计和制备提供指导，具有重要的科学意义和潜在应用价值。

铅卤钙钛矿材料同时具有优异的光伏和发光性能，在高性能太阳能电池和发光器件方面均极具应用前景。但钙钛矿在光辐照下的不稳定性是其应用的一大制约，目前对其机理研究还不够深入。本项目按研究计划从陷阱态的影响入手，从光生载流子的复合角度理解其物理机制。我们以溶液法制备的钙钛矿为研究对象，开展了钙钛矿高质量薄膜、单晶及低维结构材料的可控制备、钙钛矿陷阱态参与的载流子复合机理、钙钛矿光辐照不稳定性机理、以及钙钛矿光辐照稳定性的提升方法等4方面研究，阐明了光生载流子复合机制，并提出模型解释光辐照下钙钛矿不稳定性的机理。在此基础上，尝试了碱金属掺杂、气相离子交换等方法，提升钙钛矿光辐照稳定性，钙钛矿准二维薄膜可承受81 W/cm^2的连续光辐照保持光谱稳定。本项目研究将丰富铅卤钙钛矿材料的知识体系，为钙钛矿材料和光电子器件的设计和制备提供指导，具有重要的科学意义和潜在应用价值。