Electrochemical impedance analysis of perovskite–electrolyte interfaces

Abstract

The flat band potentials and carrier densities of spin coated and sprayed MAPbI₃, FA_0.85Cs_0.15PbI₃, and MAPbBr₃ perovskite films were determined using the Mott–Schottky relation. The films developed a space charge layer and exhibited p-type conduction with a carrier concentration of ∼10¹⁶ cm⁻³ for spin coated films. Electrochemical impedance spectra showed typical space charge impedance at frequencies >1 kHz, and an exceptional high capacitance at frequency <1 kHz owing to an ion diffusion component.