Intrinsic Raman signatures of pristine hybrid perovskite CH3NH3PbI3 and its multiple stages of structure transformation

Abstract

By performing spatially resolved Raman and photoluminescence spectroscopy with different illumination conditions, we have achieved a unified understanding towards the spectroscopy signatures of the organic-inorganic hybrid perovskite, transforming from the pristine state (CH₃NH₃PbI₃ or MAPbI₃) to fully degraded state (i.e., PbI₂), for samples with varying crystalline domain size from mesoscopic scale to macroscopic size, synthesized by three different techniques.