Perovskite solar cells (PSCs) have emerged as one of the most promising next-generation photovoltaic technologies owing to their high power conversion efficiencies, low-cost fabrication, defect tolerance, and compatibility with flexible and lightweight substrates. Despite rapid advances in device performance, operational stability remains a major challenge to their widespread commercialization. Among the various degradation mechanisms affecting PSCs, reverse-bias-induced degradation has attracted increasing attention because photovoltaic modules operating under real-world conditions are frequently subjected to reverse-voltage stress caused by partial shading, and cell mismatch. Reverse bias accelerates several degradation processes in PSCs, including ion migration, interfacial charge accumulation, and chemical decomposition of the perovskite absorber and charge transport layers. Furthermore, localized heating under reverse-bias conditions can induce thermal degradation, phase segregation, electrode corrosion, and mechanical failure, significantly reducing device lifetime. While some of these degradation processes are reversible, others cause permanent damage that irreversibly compromises device performance.

In this work, we present a comprehensive investigation of the effects of short-term reverse-bias stress on the stability of PSCs using a multimodal characterization approach. Photoluminescence (hyperspectral) and electroluminescence imaging, Kelvin probe force microscopy, and current density–voltage (J–V) measurements were employed to investigate reverse-bias-induced degradation across multiple length scales, from the macroscopic to the nanoscale. The devices were subjected to reverse-bias stress for a short duration (~20 min), and their subsequent evolution was monitored over extended timescales. Our results reveal that reverse-bias stress activates both reversible and irreversible degradation mechanisms. The reversible degradation is primarily associated with ion migration and fully recovers within approximately one hour after the stress is removed. However, reverse-bias exposure also initiates irreversible degradation pathways that continue to deteriorate device performance over time. These irreversible processes degrade the perovskite absorber, damage the interfacial layers, and promote electrode corrosion. The findings provide valuable insights into the mechanisms underlying reverse-bias-induced degradation and establish practical design guidelines for developing more robust and reliable PSCs. By addressing one of the key reliability challenges facing perovskite photovoltaics, this work contributes to the development of durable, high-performance solar cells suitable for large-scale module integration and long-term outdoor operation.