Formamidinium lead triiodide (FAPbI₃) with stable black perovskite phase and without significantly changing its bandgap is demonstrated by the incorporation of CaCl₂. More incorporated CaCl₂ in FAPbI₃ creates a desirable crystal structure, satisfying the Goldschmidt tolerance factor, and thereby stabilizing black perovskite phase under ambient conditions. However, more incorporated CaCl₂ in FAPbI₃ is likely to degrade the perovskite due to its hygroscopic characteristics. In addition, the incorporated CaCl₂ in FAPbI₃ solution reduces solubility, causing the formation of smaller crystal grains and pinholes due to quick precipitation during the non-solvent dripping crystallization process. Accordingly, 5 % CaCl₂ incorporated FAPbI₃ films have the best phase stability and solar cell performance with 18.0 % of power conversion efficiency at 1 sun condition.

通过掺入 CaCl ₂证明了三碘化甲脒铅 (FAPbI ₃ ) 具有稳定的黑色钙钛矿相并且没有显着改变其带隙。在 FAPbI _{3 中}更多掺入的 CaCl ₂产生了理想的晶体结构，满足 Goldschmidt 容差因子，从而在环境条件下稳定黑色钙钛矿相。然而，由于钙钛矿的吸湿特性，在 FAPbI _{3 中}掺入更多的 CaCl ₂可能会降解钙钛矿。此外，FAPbI _{3 中}掺入的 CaCl ₂溶液降低了溶解度，由于在非溶剂滴落结晶过程中快速沉淀，导致形成较小的晶粒和针孔。因此，掺入5% CaCl _{2 的}FAPbI ₃薄膜具有最佳的相位稳定性和太阳能电池性能，在 1 个阳光条件下具有 18.0% 的功率转换效率。