Quantification of mobile ions in perovskite solar cells with thermally activated ion current measurements

TL;DR

This paper introduces a novel thermally activated ion current (TAIC) measurement technique that quantifies mobile ions in perovskite solar cells, providing insights into ion density, diffusion, and activation energy in a single test.

Contribution

The study presents a new method for characterizing mobile ions in perovskite solar cells using TAIC, enabling simultaneous measurement of multiple ion parameters in one temperature sweep.

Findings

Higher activation energy in triple-cation devices

Lower diffusion coefficient in triple-cation devices

TAIC effectively distinguishes different mobile ion species

Abstract

Mobile ions play a key role in the degradation of perovskite solar cells, making their quantification essential for enhancing device stability. Various electrical measurements have been applied to characterize mobile ions. However, discerning between different ionic migration processes can be difficult. Furthermore, multiple measurements at different temperatures are usually required to probe different ions and their activation energies. Here, we demonstrate a new characterization technique based on measuring the thermally activated ion current (TAIC) of perovskite solar cells. The method reveals density, diffusion coefficient, and activation energy of mobile ions within a single temperature sweep and offers an intuitive way to distinguish mobile ion species. We apply the TAIC technique to quantify mobile ions of MAPbI3 and triple-cation perovskite solar cells. We find a higher activation energy and a lower diffusion coefficient in the triple-cation devices. TAIC measurements are a simple yet powerful tool to better understand ion migration in perovskite solar cells.