Reliable Measurement of Ionic and Electronic Defects in Inorganic CsPbBr ₃ Perovskite Solar Cells

Metal halide perovskites demonstrate exceptional optoelectronic properties but face stability issues due to ion migration. This study investigates ion density, ion mobility, and electronic defects in CsPbBr3 devices with and without organic p-layers, by using Bias-Assisted Charge Extraction (BACE) and Mott–Schottky methods over temperatures of 25 to 125 °C. We find that reliable estimates of mobile ion density through Mott–Schottky and BACE methods are only achieved under conditions that fully activate the ionic response. Elevated temperatures induce thermal activation of ionic responses by increasing mobility, allowing consistent quantification of ion parameters. BACE measurements demonstrate that ion mobility and concentration increase with temperature, and Br– activation energies can be calculated through ion time-of-flight. Alternatively, Mott–Schottky measurements exhibit high- and low-frequency plateaus corresponding to electronic and ionic defects, respectively. We show that organic hole transport layers induce measurement inaccuracies and larger mobile ion concentrations, whereas devices without these layers do not exhibit the same issues.