Consistent\nInterpretation of Time- and Frequency-Domain\nTraces of Ion Migration in Perovskite Semiconductors

The migration of mobile ions through the metal halide\nperovskite\nlayer is still one of the main reasons for the poor stability of perovskite\nsolar cells, LEDs, and photodetectors. To characterize mobile ions\nin the perovskite layer, time- and frequency-based electrical measurements\nare promising techniques. However, the presence of transport layers\ncomplicates their interpretation, limiting the information about mobile\nions that can be extracted, and it is not clear how different features\nin frequency- and time-domain measurements relate to mobile ions.\nHere, we characterize a transport-layer-free device with capacitance\nfrequency, capacitance transient, and current transient measurements\nin the dark, under illumination, and at different temperatures. We\nextract characteristic ionic signatures from the measurements, which\nwe reproduce with drift-diffusion simulations for each technique.\nThis allows us to explain the origins of the different ionic signatures,\nadvancing our understanding of how electronic characterization techniques\ncan be used to study the properties of mobile ions.