Focused Ion Beam–Transmission Electron Microscopy Characterizations in Perovskite‐Based Optoelectronic Device: Applications, Challenges, and Perspectives

In recent years, the rapid development of perovskite‐based optoelectronic devices imposes requirements of obtaining atomic‐scale information of perovskite. Focused ion beam‐transmission electron microscopy (FIB–TEM) has emerged as a powerful tool due to its distinct advantages such as nanoscale precision sample preparation and atomic‐scale imaging. Herein, typical applications of FIB–TEM in perovskite studies were reviewed based on its functions, such as microstructure and defect probing, phase transition and ion migration path, lattice strain, and carrier recombination behavior. Current challenges and related possible strategies of FIB–TEM were also summarized and discussed. Last, future directions of FIB–TEM in perovskite studies were proposed, which hopefully will facilitate the employment of such technique and guide the coming research hotspots.