Trapped charge driven degradation of perovskite solar cells

TL;DR

This paper uncovers that trapped charges at grain boundaries cause irreversible degradation in perovskite solar cells, explaining why light exposure accelerates deterioration and how moisture interacts with trapped charges to induce decomposition.

Contribution

It introduces a novel experimental approach revealing trapped charges as the key factor in perovskite degradation, advancing understanding of stability issues.

Findings

Trapped charges trigger irreversible degradation along grain boundaries.

Light soaking accelerates degradation due to charge trapping.

Moisture causes reversible hydration unless combined with trapped charges.

Abstract

Perovskite solar cells have shown fast deterioration during actual operation even with encapsulation, but its mechanism has been elusive. We found the fundamental mechanism for irreversible degradation of perovskite materials in which trapped charges regardless of the polarity play a decisive role. A novel experimental setup utilizing different polarity ions revealed that the moisture induced irreversible dissociation of perovskite materials is triggered by charges trapped along grain boundaries. Our finding clearly explained the intriguing observations why light soaking induces irreversible degradation while in the dark, moisture only causes reversible hydration, and why degradation begins from different side of interface for different charge extraction layers. The deprotonation of organic cations by trapped charge induced local electric field is attributed to the initiation of irreversible decomposition.