Recently, lead‐free double perovskites have emerged as a promising environmentally friendly photovoltaic material for their intrinsic thermodynamic stability, appropriate bandgaps, small carrier effective masses, and low exciton binding energies. However, currently no solar cell based on these double perovskites has been reported, due to the challenge in film processing. Herein, a first lead‐free double perovskite planar heterojunction solar cell with a high quality Cs₂AgBiBr₆ film, fabricated by low‐pressure assisted solution processing under ambient conditions, is reported. The device presents a best power conversion efficiency of 1.44%. The preliminary efficiency and the high stability under ambient condition without encapsulation, together with the high film quality with simple processing, demonstrate promise for lead‐free perovskite solar cells.

中文翻译：

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无铅钙钛矿太阳能电池的曙光：高稳定双钙钛矿Cs2AgBiBr6薄膜

近年来，无铅双钙钛矿因其固有的热力学稳定性、适当的带隙、小载流子有效质量和低激子结合能而成为一种有前景的环保光伏材料。然而，由于薄膜加工的挑战，目前还没有基于这些双钙钛矿的太阳能电池的报道。在此，报道了第一个无铅双钙钛矿平面异质结太阳能电池，其具有高质量Cs ₂ AgBiBr ₆薄膜，在环境条件下通过低压辅助溶液加工制造。该器件的最佳功率转换效率为 1.44%。无需封装的环境条件下的初步效率和高稳定性，加上加工简单的高薄膜质量，证明了无铅钙钛矿太阳能电池的前景。