北京科技大学廖庆亮团队报道了外部能量刺激下卤化钙钛矿的表面动态演变。相关研究成果发表在2024年2月2日出版的《国家科学评论》。

跟踪金属卤化物钙钛矿的表面动态演变对于理解光电性质和本征不稳定性的相应基本原理至关重要。然而，由于钙钛矿的挥发性元素和软晶格性质，一些重要的动力学行为仍不清楚。

该文中，研究人员已经开发了一种通过表面敏感探测技术集成的超高真空（UHV）互连系统，以在给定的能量刺激下原位研究CH₃NH₃PbBr₃的新解理表面。在此基础上，详细阐明了钙钛矿的三步化学分解途径。同时，揭示了在能量激励下钙钛矿表面晶体结构从立方相到四方相的演变过程。伴随着化学成分和晶体结构的演化，还准确地确定了电子结构的变化，包括能级位置、空穴有效质量和Rashba分裂。

这些发现为钙钛矿的光电性质的物理起源和分解机制提供了清晰的视角。

附：英文原文

Title: The dynamic surface evolution of halide perovskites induced by external energy stimulation

Author: Cheng, Feiyu, Wang, Pengdong, Xu, Chenzhe, Liao, Qingliang, Zhang, Suicai, Sun, Haochun, Fan, Wenqiang, Liu, Guodong, Li, Zhiyun, Kong, Yaping, Wang, Li, Li, Fangsen, Kang, Zhuo, Zhang, Yue

Issue&Volume: 2024-02-02

Abstract: Tracking the dynamic surface evolution of metal halide perovskite is crucial for understanding the corresponding fundamental principles of photoelectric properties and intrinsic instability. However, due to the volatility elements and soft lattice nature of perovskites, several important dynamic behaviors remain unclear. Here, an ultra-high vacuum (UHV) interconnection system integrated by surface-sensitive probing techniques has been developed to in-situ investigate the freshly cleaved surface of CH3NH3PbBr3 under given energy stimulation. On this basis, the detailed three-step chemical decomposition pathway of perovskites has been clarified. Meanwhile, the evolution of crystal structure from cubic phase to tetragonal phase on the perovskite surface has been revealed under energy stimulation. Accompanied by chemical composition and crystal structure evolution, electronic structure changes including energy level position, hole effective mass, and Rashba splitting have also been accurately determined. These findings provide a clear perspective on the physical origin of optoelectronic properties and the decomposition mechanism of perovskites.

DOI: 10.1093/nsr/nwae042

Source: https://dx.doi.org/10.1093/nsr/nwae042