Quantifying mobile ions and electronic defects in perovskite-based devices with temperature-dependent capacitance measurements: Frequency vs time domain

Perovskites have proven to be a promising candidate for highly efficient solar cells, light-emitting diodes, and x-ray detectors, overcominglimitations of inorganic semiconductors. However, they are notoriously unstable. The main reason for this instability is the migration ofmobile ions through the device during operation as they are mixed ionic–electronic conductors. Here, we show how measuring the capacitancein both the frequency and the time domain can be used to study ionic dynamics within perovskite-based devices, quantifying activation energy,diffusion coefficient, sign of charge, concentration, and the length of the ionic double layer in the vicinity of the interfaces. Measuring thetransient of the capacitance furthermore allows for distinguishing between ionic and electronic effects.