Inorganic cesium lead halide perovskites with superb thermal stability show promise to fabricate long-term operational photovoltaic devices. However, the cubic phase (α) of CsPbI₃ with an appropriate band gap is unstable in air. We discover that highly stable α-CsPbI₃ can be obtained in dry air (temperature: 20–30 °C; humidity: 10–20%) by replacing PbI₂ with HPbI₃ in a one-step deposition solution. Furthermore, the band gap of HPbI₃-processed α-CsPbI₃ is advantageously reduced from 1.72 to 1.68 eV due to the existence of tensile lattice strain. By employing such an α-CsPbI₃ film in carbon-based perovskite solar cells (C-PSCs), a power conversion efficiency (PCE) of 9.5% is achieved, which is a record value for the α-CsPbI₃ PSCs without hole transport material. Most importantly, over 90% of the initial PCE is retained for nonencapsulated devices after 3000 h of storage in dry air. Therefore, HPbI₃-based one-step deposition presents a promising strategy to prepare high-performance and air-stable α-CsPbI₃ PSCs.

中文翻译：

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高度空气稳定的碳基α-CsPbI ₃钙钛矿太阳能电池与加宽的光谱分析

具有极好的热稳定性的无机铯卤化钙铅钙钛矿显示出可以制造长期可操作的光伏器件的前景。但是，具有适当带隙的CsPbI ₃的立方相（α）在空气中不稳定。我们发现，高度稳定的α-CsPbI ₃可以在干燥的空气来获得（温度：20-30℃;湿度：10-20％），用碘化铅₂与HPbI ₃在单步沉积的解决方案。此外，HPbI的带隙₃ -processedα-CsPbI ₃有利地从1.72减小到1.68电子伏特由于拉伸晶格应变的存在。通过采用这样的α-CsPbI ₃在基于碳的钙钛矿太阳能电池（C-的PSC）膜，9.5％的功率转换效率（PCE）实现，这对于α-CsPbI一个记录值_3点的PSC没有空穴传输材料。最重要的是，在干燥空气中存储3000小时后，非封装设备保留了超过90％的初始PCE。因此，HPbI ₃为基础的一步法沉积呈现有希望的策略来制备高性能和空气稳定的α-CsPbI ₃的PSC。