Residual tensile strain impedes the improvement of efficiency and intrinsic stability of perovskite solar cells (PSCs), resulting from the perovskite lattice distortion and different thermal expansion coefficients. Herein, we propose a molecule-triggered strain regulation and interfacial passivation strategy to enhance the efficiency and stability (especially photostability) of PSCs, which utilizes the [2 + 2] cycloaddition reaction of 6-bromocoumarin-3-carboxylic acid ethyl ester (BAEE), consuming the incident UV light to suppress the tensile strain evolution. Meanwhile, the BAEE can form a strong bond with NiO_x, assisting the perovskite growth and the interface defect passivation. We obtain the efficiency of 26.32% (certified 26.08%), the open-circuit voltage (V_oc) up to 1.201 V with low V_oc loss (0.342 V), as well as the long-term stability (continuous 365 nm UV illumination: T₉₀ > 110 h in N₂, T₉₀ > 6 h in ambient air, and continuous LED white light irradiation at 100 mWcm⁻²: T₉₀ > 1,000 h).

中文翻译：

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分子触发的应变调控和界面钝化，用于高效倒置钙钛矿太阳能电池


残余拉伸应变阻碍了钙钛矿太阳能电池 （PSC） 效率和本征稳定性的提高，这是由钙钛矿晶格畸变和不同的热膨胀系数引起的。在此，我们提出了一种分子触发的应变调控和界面钝化策略，以提高 PSC 的效率和稳定性（尤其是光稳定性），它利用 6-溴香豆素-3-羧酸乙酯 （BAEE） 的 [2 + 2] 环加成反应，消耗入射紫外光来抑制拉伸应变的演变。同时，BAEE 可以与 NiO_x 形成牢固的键合，有助于钙钛矿生长和界面缺陷钝化。我们获得了 26.32% 的效率（认证 26.08%），开路电压 （V_oc） 高达 1.201 V，V_oc 损耗低 （0.342 V），以及长期稳定性（连续 365 nm 紫外照明：N₂ 中 T₉₀ > 110 小时，环境空气中 T₉₀ > 6 小时，以及 100 mWcm-2 的连续 LED 白光照射）： T₉₀ > 1,000 h）.