Coupled Slow and Fast Charge Dynamics in Cesium Lead Bromide Perovskite

Lead halide perovskites show slow (from seconds to minutes) and fast (milliseconds to submicroseconds) charge dynamics. We use scanning Kelvin probe microscopy and dissipation microscopy to probe these charge dynamics in a thin film of CsPbBr 3 . We demonstrate the existence of a light-intensity-dependent τ fast in CsPbBr 3 that exhibits a slow, activated, intensity-independent recovery in the dark. The observed τ fast, while highly light-dependent, remained essentially unchanged when the light was turned off, taking 10 ± 2 s to relax at room temperature. The data presented here show direct evidence that the slow and fast charge dynamics ubiquitously seen in lead-halide perovskites have a common origin related to a highly activated charge redistribution.