The studies of perovskite film in the perovskite solar cells (PSCs) mainly focus on their crystallization and growth, but the reactions that happen in the precursor solutions are still not very clear, which is leading to the bad reproducibility for high-efficient devices. We demonstrated that, in the methylammonium- and formamidinium-mixed organic cation perovskite solution, the methylamine molecule could be first generated from the deprotonation of methylammonium iodide, and then condensate with formamidinium iodide to form N-methyl formamidinium iodide and N, N′-dimethyl formamidinium iodide. The triethyl borate was carried out as a stabilizer to restrain the deprotonation of methylammonium iodide in the precursor solutions, resulting in the elimination of the impurity phase in perovskite films. We think that the introduction of stabilizer in the perovskite precursor solution will become a common strategy for mixed-organic-cation PSCs in the future to improve the reproducibility and efficiency.

钙钛矿太阳能电池（PSC）中钙钛矿薄膜的研究主要集中在其结晶和生长，但是在前体溶液中发生的反应仍然不是很清楚，这导致了高效器件的重现性差。我们证明，在甲基铵和甲ami混合的有机阳离子钙钛矿溶液中，甲胺分子首先可以由碘化甲铵的去质子化生成，然后与碘化甲铵缩合形成N-甲基甲碘化铵和N，N′-二甲基甲ami碘化物。硼酸三乙酯被用作稳定剂以抑制前体溶液中碘化甲基铵的去质子化，从而消除了钙钛矿薄膜中的杂质相。我们认为，在钙钛矿前体溶液中引入稳定剂将成为未来混合有机阳离子PSC改善重复性和效率的通用策略。