  High-resolution TEM (HRTEM) is a powerful tool for structure
characterization. However, methylammonium lead iodide (MAPbI3) perovskite is
highly sensitive to electron beams and easily decompose into lead iodide
(PbI2). Universal misidentifications that PbI2 is incorrectly labeled as
perovskite are widely exist in HRTEM characterization, which would negatively
affect the development of perovskite research field. Here misidentifications in
MAPbI3 perovskite calibration are summarized, classified and corrected based on
corresponding electron diffraction (ED) simulations. Corresponding
crystallographic parameters of intrinsic tetragonal MAPbI3 and the confusable
hexagonal PbI2 are also presented clearly. Finally, the method of proper phase
identification and some ways to control the radiation damage in HRTEM are
provided. This work paves the way to avoid misleadings in HRTEM
characterization of perovskite and other electron beam-sensitive materials in
the future.
