Today's state‐of‐the‐art perovskite solar cells (PSCs) are utilizing polycrystalline perovskite thin films via solution‐processing at low temperature (<150 °C). It is extremely significant to enlarge grain size and passivate trap states for perovskite thin films to achieve high power conversion efficiency. Herein, a strategy for defect passivation of perovskite films via metal ion Ni²⁺ is for the first time reported. It is found that addition of Ni²⁺ can significantly generate polyporous PbI₂ films due to a different solubility between NiCl₂ and PbI₂ which benefits penetration of MAI and thus formation of large grain perovskite films eventually. It further demonstrated that Ni²⁺ ions can effectively passivate PbI₃⁻ antisite defects and restrain the generation of Pb⁰ by interacting with the under‐coordinated halide anions and halide‐rich antisites. Therefore, introducing moderate Ni²⁺ ions result in a significant increase in photoluminescence lifetime from 285 to 732 ns. Accordingly, a power conversion efficiency of 20.61% can be achieved for the 3% Ni²⁺ addition‐based PSCs with an enhanced cell stability under ambient conditions. This work provides a promising route toward perovskite films featuring with high crystallinity and low trap‐density.

中文翻译：

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通过镍钝化的高效钙钛矿太阳能电池

当今最先进的钙钛矿太阳能电池（PSC）通过在低温（<150°C）下进行固溶处理来利用多晶钙钛矿薄膜。增大钙钛矿薄膜的晶粒尺寸并钝化陷阱态以实现高功率转换效率非常重要。在此，首次报道了通过金属离子Ni ²⁺进行钙钛矿膜的缺陷钝化的策略。已经发现，由于NiCl ₂和PbI ₂之间的溶解度不同，因此添加Ni ²⁺可以显着产生多孔PbI ₂膜，这有利于MAI的渗透并最终形成大晶粒的钙钛矿膜。进一步证明了Ni ²⁺离子可以有效地钝化碘化铅₃ ^-反位缺陷和抑制铅的生成⁰通过与下协调卤素阴离子和富含卤化物antisites交互。因此，引入适度的Ni ²⁺离子可使光致发光寿命从285 ns显着增加到732 ns。因此，对于添加了3％Ni ²⁺的PSC，在环境条件下具有更高的电池稳定性，可以实现20.61％的功率转换效率。这项工作为生产具有高结晶度和低陷阱密度的钙钛矿薄膜提供了一条有希望的途径。