Surface Photovoltage Spectroscopy Study of Ultrasonically Sprayed-Aerosol CH3NH3PbI3 Perovskite Crystals

A simple deposition process for preparing crystalline semiconductors with low degrees of disorder is of paramount interest for both device applications and research investigations. This study centers on the ultrasonically sprayed-aerosol based approach for preparing crystals of methylammonium lead trihalide perovskite (CH3NH3PbI3). The surface photovoltage (SPV) spectra are found to depend strongly on the preparation conditions, with the SPV signals (below the material's band gap) providing information on the defect states. The measured values of tail states near the band gap (E-t) are found to be about 21 and 52meV for the CH3NH3PbI3 crystals prepared by the ultrasonically sprayed-on and spun casting approaches, respectively.