Cesium-based all-inorganic perovskite solar cells (PSCs), such as CsPbIBr₂ PSCs, have attracted wide attention for good thermal and wet stability, but the low open-circuit voltage (V_oc) mainly caused by the inadequate coverage of CsPbIBr₂ films is the main reason for limiting their development. The CsPbIBr₂ films grown on TiO₂ substrate directly have a large number of pinholes, which bring a lot of defects and lead to an increase of nonradiative recombination. In this work, a strategy extended for CsPbIBr₂ films by precoating methylammonium acetate (MAAc) ionic liquid onto a TiO₂ layer before depositing the CsPbIBr₂ film is demonstrated. The uniformly distributed MA⁺ will be the nucleation center at the bottom of the CsPbIBr₂ film, which exhibited a notable impact on the crystallization kinetics of CsPbIBr₂ films. This effect simultaneously enhanced the crystal quality of the CsPbIBr₂ film and interfacial contact between the electron transporting layer (ETL) and CsPbIBr₂ layer. It is instrumental in decreasing the trap state density, suppressing nonradiative recombination, and extracting the charge carriers. Therefore, the stability of the optimized device has been improved considerably, and the champion power conversion efficiency (PCE) is up to 8.85% with a high V_oc of 1.26 V. Benefiting from passivation, the PSC with 2 M MAAc IL interfacial modification remains 82% of its initial PCE after 30 days of exposing the device to ambient air at room temperature.

中文翻译：

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MAAc 离子液体辅助缺陷钝化用于高效稳定的 CsPbIBr2 钙钛矿太阳能电池

铯基全无机钙钛矿太阳能电池（PSCs），如CsPbIBr ₂ PSCs，因其良好的热稳定性和湿稳定性而受到广泛关注，但开路电压（V _oc）低主要是由于CsPbIBr _{2 的}覆盖不足造成的电影是限制其发展的主要原因。直接在TiO ₂衬底上生长的CsPbIBr ₂薄膜具有大量的针孔，带来大量缺陷，导致非辐射复合增加。在这项工作中，通过在沉积 CsPbIBr ₂之前将甲基乙酸铵 (MAAc) 离子液体预涂覆到 TiO ₂层上，扩展了 CsPbIBr ₂薄膜的策略影片进行了演示。均匀分布的MA ⁺将在CsPbIBr底部的核中心₂膜，其表现出对CsPbIBr的结晶动力学有显着影响₂膜。这种效应同时增强了 CsPbIBr ₂膜的晶体质量以及电子传输层 (ETL) 和 CsPbIBr ₂层之间的界面接触。它有助于降低陷阱态密度、抑制非辐射复合和提取电荷载流子。因此，优化的设备的稳定性得到了显着改善，并且冠军功率转换效率（PCE）为至多8.85％的高V _OC 1.26 V。得益于钝化，具有 2 M MAAc IL 界面改性的 PSC 在将器件暴露于室温环境空气 30 天后仍保持其初始 PCE 的 82%。