Postsynthesis Transformation of Halide Perovskite Nanocrystals

The high sensitivity of as-synthesized purified perovskite nanocrystals (NCs) to diverse conditions such as solvent polarity, aging, ligand treatment, heat, light, pressure, and humidity affects the surface chemistry. Ligand dynamics (adsorption and desorption) on the surfaces of the NCs plays a key role in the postsynthesis transformation of the morphology and crystallographic phase. Although the ligand destabilization mechanism changes the morphology and crystal structure of the pristine NCs, it also opens up opportunities to obtain interesting morphologies or different crystallographic phases with modified properties. There remain significant challenges in understanding the mechanism of postsynthesis transformation processes. This Focus Review aims to provide a survey of the current state of the postsynthesis transformation of perovskite NCs. The chemistry of controlling the resultant morphology and crystal structure of NCs in the postsynthesis conditions is examined. A more explorative direction for controlling the fundamental properties of the perovskite NCs through postsynthesis transformation is presented.