Ion Migrations in Lead Halide Perovskite Single Crystals with Different Halide Components

The ion migrations in lead halide perovskite (LHP)-based devices are complex processes due to the generation of charges and migration multipaths. The migrating ions are generated mainly from element defects and dislocation defects, and transport along paths of element vacancies and grain boundaries. In this regard, it is of interest to investigate the different influences of the two defect types and paths. Herein, the current-voltage hysteresis and X-ray photoelectron spectra of almost-dislocation-free LHP single crystals (LHPSCs) with different halide components are investigated. The ions cannot migrate in iodine-based LHPSCs. A decrease in halide vacancy content in a bromine-chlorine-based perovskite single crystal can effectively limit the ion migration. This study provides useful insights to understand the different dominant factors determining the ion migration in LHPs.