Stability of perovskite solar cells (PSCs) under light, heat, humidity and their combinations have been notably improved recently. However, PSCs have poor reverse-bias stability that limits their real-world application. Here we report a systematic study on the degradation mechanisms of p–i–n structure PSCs under reverse bias. The oxidation of iodide by injected holes at the cathode side initialize the reverse-bias-induced degradation, then the generated neutral iodine oxidizes metal electrode such as copper, followed by drift of Cu⁺ into perovskites and its reduction by injected electrons, resulting in localized metallic filaments and thus device breakdown. A reinforced barrier with combined lithium fluoride, tin oxide and indium tin oxide at the cathode side reduces device dark current and avoids the corrosion of Cu⁰. It dramatically increases breakdown voltage to above −20 V and improved the T₉₀ lifetime of PSCs to ~1,000 h under –1.6 V. The modified minimodule also maintained over 90% of its initial performance after 720 h of shadow tests.

钙钛矿太阳能电池（PSC）在光、热、湿度及其组合下的稳定​​性最近得到显着改善。然而，PSC 的反向偏置稳定性较差，限制了其实际应用。在这里，我们报告了反向偏压下 p-i-n 结构 PSC 降解机制的系统研究。阴极侧注入空穴对碘化物的氧化引发反向偏压诱导降解，然后生成的中性碘氧化铜等金属电极，随后Cu ⁺漂移到钙钛矿中并被注入电子还原，从而产生局域化金属丝，从而导致设备故障。阴极侧由氟化锂、氧化锡和氧化铟锡组合而成的强化阻挡层减少了器件暗电流并避免了Cu ⁰的腐蚀。它将击穿电压显着提高至−20 V 以上，并将 PSC 的T ₉₀寿命在 –1.6 V 下提高至约 1,000 小时。经过 720 小时的阴影测试后，修改后的微型模块还保持了 90% 以上的初始性能。