Architecture Optimization Dramatically Improves Reverse Bias Stability in Perovskite Solar Cells: A Role of Polymer Hole Transport Layers

TL;DR

This study shows that optimizing device architecture, especially using polymer hole transport layers and stable electrodes, significantly enhances reverse bias stability in perovskite solar cells, enabling higher breakdown voltages and recovery after stress.

Contribution

The paper introduces a novel device architecture approach that improves reverse bias stability in perovskite solar cells through polymer hole transport layers and stable electrodes.

Findings

Breakdown voltages exceeding -15 V achieved.

Complete performance recovery after stress at -7 V for 9 hours.

Electrochemical stability and reaction rates influence reverse bias stability.

Abstract

We report that device architecture engineering has a substantial impact on the reverse bias instability that has been reported as a critical issue in commercializing perovskite solar cells. We demonstrate breakdown voltages exceeding -15 V in typical pin structured perovskite solar cells via two steps: i) using polymer hole transporting materials; ii) using a more electrochemically stable gold electrode. While device degradation can be exacerbated by higher reverse bias and prolonged exposure, our as-fabricated perovskite solar cells completely recover their performance even after stressing at -7 V for 9 hours both in the dark and under partial illumination. Following these observations, we systematically discuss and compare the reverse bias driven degradation pathways in perovskite solar cells with different device architectures. Our model highlights the role of electrochemical reaction rates and species in dictating the reverse bias stability of perovskite solar cells.