Phase Segregation Dynamics in Mixed-Halide Perovskites Revealed by Plunge-Freeze Cryogenic Electron Microscopy

作     者：Fan, Qingyuan Li, Yanbin Vigil, Julian A. Jiang, Zhiqiao Nandi, Partha Colby, Robert Zhang, Chensong Cui, Yi Karunadasa, Hemamala I. Lindenberg, Aaron M. 

作者机构：Department of Materials Science and Engineering Stanford University StanfordCA94305 United States  SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Stanford PULSE Institute SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Department of Chemistry Stanford University StanfordCA94305 United States Department of Chemical Engineering Stanford University StanfordCA94305 United States Corporate Strategic Research ExxonMobil Research and Engineering 1545 US Highway 22 East AnnandaleNJ08807 United States ExxonMobil Technology and Engineering Company AnnandaleNJ08801 United States Department of Molecular and Cellular Physiology StanfordCA94305 United States 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2024年

核心收录：

主　　题：Grain boundaries 

摘      要：Mixed-halide lead perovskites, with photoexcited charge-carrier properties suitable for high-efficiency photovoltaics, hold significant promise for high-efficiency tandem solar cells. However, phase segregation under illumination, where an iodide-rich phase forms carrier trap states, remains a barrier to applications. This study employs plunge-freeze cryogenic electron microscopy to visualize nanoscale phase segregation dynamics in CsPb(BrxI1–x)3 films. By rapidly freezing the illuminated samples, we preserve transient photoexcited ion distributions for high-resolution structural and compositional analysis at the nanoscale. Cryogenic scanning transmission electron microscopy techniques (EELS, 4D-STEM) captured the dynamics of photo-induced iodine migration from grain boundaries to centers, identified the buildup of anisotropic strain, and captured the heterogeneous evolution of this process within a single grain. These findings provide new insights into microscopic phase segregation mechanisms and their dynamics, enhancing our understanding of mixed-halide perovskite photostability. © 2024, CC BY-NC-ND.