Probing atomic structure of beam-sensitive energy materials in their native states using cryogenic transmission electron microscopes

Organic–inorganic hybrid perovskite nanoplatelets (NPLs) have emerged as promising materials for solar energy. However, the structural instability under electron beam hinders further probing and understanding of its crystalline structures and defects at the atomic scale. Taking methylammonium bromide perovskite methylammonium lead bromide (CHNHPbBr (MAPbBr)) perovskite NPLs as model material, we performed atomic-scale characterization of the native state of the hybrid perovskite solar cell material in different states using ultra-low-dose cryo-TEM imaging. With a series of observation at different growth time, we revealed the growth pattern of such MAPbBr material from an initially stacked slices with rotational moiré fringes to a perfect single-crystalline structure of NPLs. Our high-resolution cryo-TEM further enabled the atomic-scale investigations of solid electrolyte interphase (SEI) and sodium (Na) dendrite materials, which can largely impact the safety and life of batteries. This study offers insights on the atomic scale characterization of a wide variety of beam-sensitive materials, inspiring us to probe more materials with cryo-transmission electron microscopes (TEM).