Inorganic perovskite CsPbI₃ has been studied as a promising alternative light‐absorbing material for photovoltaic application due to its suitable band gap for converting solar light and enhanced stability toward ambient conditions compared to the organic–inorganic halide perovskite. However, the photoactive α‐phase of CsPbI₃ can only be stabilized at a high temperature and the phase transition from α‐phase to δ‐phase easily occurs at room temperature. Herein, ytterbium (III) chloride (YbCl₃) as a bifunctional additive is introduced into the perovskite precursor to stabilize the black α‐phase, and high‐quality CsPbI₃ films are obtained at a temperature as low as 80 °C. Yb³⁺ partly replaces Pb²⁺ to enhance the tolerance factor and favors the formation of α‐phase. The Lewis adduct complex of YbCl₃·DMSO in the perovskite film can passivate the perovskite film with reduced defects and help enhance the stability of the α‐phase. The YbCl₃‐modified planar‐type α‐CsPbI₃ perovskite solar cells show a champion power conversion efficiency of 12.4% with an impressive stability at ambient conditions. The additive induced controlled crystallization provides a simple and promising way to improve the photovoltaic performance of inorganic perovskite solar cells.

中文翻译：

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双功能氯化（（III）低温合成稳定的α-CsPbI3，用于高效无机钙钛矿太阳能电池

与有机-无机卤化物钙钛矿相比，无机钙钛矿CsPbI ₃作为一种有前途的替代光吸收材料已被研究用于光伏应用，因为它具有合适的能带隙，可转换太阳光并增强了对环境的稳定性。但是，CsPbI ₃的光敏α相只能在高温下稳定，并且在室温下很容易发生从α相到δ相的相变。在此，将作为双功能添加剂的氯化（（III）（YbCl ₃）引入钙钛矿前体中以稳定黑色α相，并在低至80°C的温度下获得高质量的CsPbI ₃膜。Yb ³⁺部分替代Pb ²⁺以提高容差因子并有利于α相的形成。钙钛矿膜中YbCl ₃ ·DMSO的Lewis加合物可以钝化钙钛矿膜，减少缺陷，并有助于增强α相的稳定性。的YbCl ₃修饰的平面型α-CsPbI ₃钙钛矿的太阳能电池显示出的12.4％与在环境条件下令人印象深刻的稳定性的冠军功率转换效率。添加剂诱导的受控结晶为改善无机钙钛矿太阳能电池的光伏性能提供了一种简单而有希望的方法。