A redox road to recovery Device longevity is a key issue for organic-inorganic perovskite solar cells. Encapsulation can limit degradation arising from reactions with oxygen and water, but light, electric-field, and thermal stresses can lead to metastable elemental lead and halide atom defects. Wang et al. show that for the lead-iodine system, the introduction of the rare earth europium ion pair Eu3+-Eu2+ can shuttle electrons and recover lead and iodine ions (Pb2+ and I−). Devices incorporating this redox shuttle maintained more than 90% of their initial power conversion efficiencies under various aging conditions. Science, this issue p. 265 A rare earth redox couple restores neutral lead and iodine defects to their ionic state. The components with soft nature in the metal halide perovskite absorber usually generate lead (Pb)0 and iodine (I)0 defects during device fabrication and operation. These defects serve as not only recombination centers to deteriorate device efficiency but also degradation initiators to hamper device lifetimes. We show that the europium ion pair Eu3+-Eu2+ acts as the “redox shuttle” that selectively oxidized Pb0 and reduced I0 defects simultaneously in a cyclical transition. The resultant device achieves a power conversion efficiency (PCE) of 21.52% (certified 20.52%) with substantially improved long-term durability. The devices retained 92% and 89% of the peak PCE under 1-sun continuous illumination or heating at 85°C for 1500 hours and 91% of the original stable PCE after maximum power point tracking for 500 hours, respectively.

中文翻译：

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Eu3+-Eu2+ 离子氧化还原梭赋予 Pb-I 钙钛矿太阳能电池操作耐久性

恢复氧化还原之路 器件寿命是有机-无机钙钛矿太阳能电池的关键问题。封装可以限制与氧气和水反应引起的降解，但光、电场和热应力会导致亚稳态元素铅和卤化物原子缺陷。王等人。表明对于铅碘系统，引入稀土铕离子对 Eu3+-Eu2+ 可以穿梭电子并回收铅和碘离子（Pb2+ 和 I-）。包含这种氧化还原穿梭机的设备在各种老化条件下都能保持 90% 以上的初始功率转换效率。科学，这个问题 p。265 稀土氧化还原对将中性铅和碘缺陷恢复到它们的离子状态。金属卤化物钙钛矿吸收体中具有软性质的成分通常在器件制造和操作过程中产生铅 (Pb)0 和碘 (I)0 缺陷。这些缺陷不仅是降低器件效率的复合中心，而且是阻碍器件寿命的退化引发剂。我们表明铕离子对 Eu3+-Eu2+ 充当“氧化还原梭”，在循环转变中同时选择性氧化 Pb0 和减少 I0 缺陷。由此产生的设备实现了 21.52%（经认证为 20.52%）的功率转换效率 (PCE)，并显着提高了长期耐用性。器件在 1 太阳连续照明或 85°C 加热 1500 小时下分别保留了 92% 和 89% 的峰值 PCE，在最大功率点跟踪 500 小时后分别保留了原始稳定 PCE 的 91%。