Atomically resolved edges and defects in lead halide perovskites.

Yuan, Biao; Wang, Zeyu; Zhang, Shuchen; Hofer, Christoph; Gao, Chuang; Chennit, Tamazouzt; Shi, Hongsheng; Wu, Xiaoyan et al. · Nature · 2025

basic_science · Level V

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Abstract

Although edges and defects constitute only a small fraction of crystalline materials, they exert an outsized impact on a material's properties. Organic-inorganic halide perovskites are promising next-generation semiconductor materials with superior cost effectiveness and interesting optoelectronic properties<sup>1-3</sup>. However, clear images of their edges have remained challenging to obtain owing to their extreme sensitivity<sup>4,5</sup>. Using truly high-speed ultralow-dose four-dimensional scanning transmission electron microscopy with dose fractionation, we perform ptychography at, to our knowledge, the lowest-dose atomic resolution to date, revealing not only the detailed atomic structure of the edges of a halide perovskite but also their structural dynamics. A majority methylammonium (MA) and iodine (I) edge termination is observed in methylammonium lead iodide (MAPbI<sub>3</sub>), and the damage rate of its edges and internal defects is found to depend on the concentration and type of vacancies present, with a preponderance of I vacancies in particular correlating with higher rates of damage.