Hysteric Influence of Grain Multiplicity in All-Inorganic Halide Perovskite Nanocrystals

Hybrid halide perovskite nanocrystals (NCs) have attracted significant attention for application in optoelectronic devices due to their excellent optical properties and low-cost synthesis. Yet their application in optoelectronic devices is limited due to the lack of understanding of their electronic properties. In this study, we investigated the influence of grain multiplicity on the hysteresis of single-grain nanocrystals (SG-NCs), multigrain nanocrystals (MG-NCs), and polycrystalline thin films (PTFs) of all-inorganic CsPbBr3 perovskite. The current-voltage characteristics of lateral ITO/CsPbBr3/ITO devices were analyzed at different scan rates and illumination levels. We found that in PTFs, hysteresis occurs over a wide voltage range due to grain boundaries facilitating ion migration, while the hysteresis is limited to a short voltage range in SG-NCs due to the polarization and ion confinement within the nanocrystals. Interestingly, MG-NCs exhibit long- and short-range hysteresis due to the presence of grain boundaries within the nanocrystal structure, while ions are confined in the nanocrystals. Hence, the presence of a grain boundary influences the hysteresis in the I-V curve. Our study provides a better understanding of the charge transport behavior of perovskite-based materials, which could further aid in developing high-performance perovskite-based memory devices for neuromorphic computing.