Bias effect on surface chemical states of CH3NH3PbBr3 hybrid perovskite single crystal: Decreasing CH3NH2 molecular defect

Abstract

A CH3NH3PbBr3 (MAPbBr3) single crystal was subjected to 2 and 10 V biasing for 10 min under ultra-high vacuum to investigate the bias effect on the surface of MAPbBr3. Under these controlled conditions, we performed high-resolution photoelectron spectroscopy on the MAPbBr3 single crystals at photon energies of 460 and 100 eV under synchrotron radiation to obtain core-level and valence structure spectra. The CH3NH2 molecular defect relative intensity area ratio decreased from 22% to 10%. It was assumed that the bias effect can induce a low density of defect states to suppress large defect-pinned energy states at the interfaces.