Visualizing Electronic Inhomogeneity in CsPbBr₃ Perovskite Nanorods

Abstract: All-inorganic perovskite nanocrystals (NCs), such as CsPbBr₃ NCs, have demonstrated promising applications in solar cells, light-emitting diodes (LEDs), electroluminescence devices, and lasing. Grain boundaries and point defects influence carrier transport in perovskite NCs, thereby impacting the device performance. We use contactless dielectric force microscopy (DFM), a novel scanning probe microscopy (SPM)-based imaging technique, to probe local electronic inhomogeneity in CsPbBr₃ nanorods (NRs). We find that while some NRs exhibit nearly homogeneous DFM responses, others behave as p-n junctions with well-defined grain boundaries. Moreover, point defects are observed in some CsPbBr₃ NRs. It is thus feasible to identify CsPbBr₃ NRs that are suitable for device fabrications based on their DFM responses.