Quantifying mobile ions in perovskite-based devices with temperature-dependent capacitance measurements: frequency versus time domain

TL;DR

This paper demonstrates how temperature-dependent capacitance measurements in frequency and time domains can quantify mobile ion dynamics in perovskite devices, aiding understanding of their stability and ionic behavior.

Contribution

It introduces a method combining frequency and time domain capacitance measurements to analyze ionic dynamics in perovskite-based devices, providing detailed quantification of ionic parameters.

Findings

Quantified activation energy and diffusion coefficient of ions.

Distinguished ionic effects from electronic effects.

Provided insights into ionic behavior near interfaces.

Abstract

Perovskites have proven to be a promising candidate for highly-efficient solar cells, light-emitting diodes, and X-ray detectors, overcoming limitations of inorganic semiconductors. However, they are notoriously unstable. The main reason for this instability is the migration of mobile ions through the device during operation, as they are mixed ionic-electronic conductors. Here we show how measuring the capacitance in 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 the transient of the capacitance furthermore allows for distinguishing between ionic and electronic effects.