Truth and Myth of Phase Coexistence in Methylammonium Lead Iodide Perovskite Thin Film Via Transmission Electron Microscopy

Hybrid organic-inorganic perovskites have attracted substantial interest as the most favorable prospective material for efficient photovoltaic and optoelectronic devices. However, their extreme sensitivity to electron beam radiation makes it difficult to obtain their intrinsic structure by transmission electron microscopy and can even lead to significant misidentifications. In 2018, the coexistence of methylammonium lead iodide (MAPbI ) in the cubic and tetragonal phase using electron microscopy and electron diffraction techniques was reported in article "Self-Organized Superlattice and Phase Coexistence inside Thin Film Organometal Halide Perovskite". Herein, however, that claim is challenged by comparing their experimental data to simulated diffraction patterns and arguing that their perovskite samples may have been damaged due to excessive electron beam irradiation. Consequently, true phase coexistence was not observed in that previously reported work, rather merely the decomposition products of MAPbI .