Predictive modeling of ion migration induced degradation in perovskite solar cells

TL;DR

This paper provides a comprehensive theoretical and numerical analysis of ion migration effects in perovskite solar cells, revealing new insights into degradation mechanisms and proposing characterization methods to improve device stability.

Contribution

It introduces a unifying theoretical framework for ion migration effects, demonstrating their impact on device performance and resilience, supported by simulations and experimental comparisons.

Findings

Ionic charges mimic dopant ions in effects.

Ion migration can improve Voc while degrading Jsc.

Champion devices show greater resilience to ion migration.

Abstract

With excellent efficiencies being reported from multiple labs across the world, device stability and the degradation mechanisms have emerged as the key aspects that could determine the future prospects of perovskite solar cells. However, the related experimental efforts remain scattered due to the lack of any unifying theoretical framework. In this context, here we provide a comprehensive analysis of ion migration effects in perovskite solar cells. Specifically, we show, for the first time, that (a) the effect of ionic charges is almost indistinguishable from that of dopant ions, (b) ion migration could lead to simultaneous improvement in Voc and degradation in Jsc - a unique observation which is beyond the realm of mere parametric variation in carrier mobility and lifetime, (c) champion devices are more resilient towards the ill effects of ion migration, and finally (d) we propose unique characterization schemes to determine both magnitude and polarity of ionic species. Our results, supported by detailed numerical simulations and direct comparison with experimental data, are of broad interest and provide a much needed predictive capability towards the research on performance degradation mechanisms in perovskite solar cells