Thiocyanate (SCN^-) has been reported to manage crystallization of perovskite films and improve their optoelectronic properties in solar cells. However, the mechanism of SCN^- in preparation of high-quality (MAFA)Pb(IBr)₃ based light-absorbing layers has not been well investigated yet. In this work, we investigate the effects of SCN^- on phase transition of (MAFA)Pb(IBr)₃ perovskite films and the corresponding device performance by introducing methylammonium thiocyanate (MASCN) in a PbI₂ precursor solution which is used to make perovskite by a two-step sequential deposition method. Characterization of the perovskite films has shown that a proper amount (1 mg/mL) of MASCN in PbI₂ can produce PbI₂-MASCN seeds which act as a nucleation center for assisting heterogeneous nucleation of the (MAFA)Pb(IBr)₃. Meanwhile, MASCN helps to effectively control crystallization of the perovskite film by obtaining preferential crystal growth orientation. Furthermore, MASCN is beneficial to eliminate residual PbI₂ and prepare perovskite films with low trap-state density. Consequently, the power conversion efficiency (PCE) of the perovskite solar cells increases from 18.36% to 20.4%. An enhanced device stability against moisture is also observed in the MASCN-treated device which exhibits 90% retention of the initial efficiency after exposed to the ambient air for 1780 h.

据报道，硫氰酸盐 (SCN ^{- ) 可控制钙钛矿薄膜的结晶并改善其在太阳能电池中的光电性能。}然而，SCN ^-在制备高质量(MAFA)Pb(IBr) ₃基光吸收层中的机理尚未得到很好的研究。在这项工作中，我们通过在用于制备钙钛矿的PbI ₂前驱体溶液中引入甲基硫氰酸铵 (MASCN) 来研究 SCN ^-对 (MAFA)Pb(IBr) ₃钙钛矿薄膜相变的影响以及相应的器件性能。两步顺序沉积法。钙钛矿薄膜的表征表明，适量（1 mg/mL）的 MASCN 在 PbI 中₂可以产生PbI ₂ -MASCN 晶种，其充当成核中心以辅助(MAFA)Pb(IBr) ₃的异质成核。同时，MASCN通过获得优先的晶体生长取向，有助于有效控制钙钛矿薄膜的结晶。此外，MASCN有利于消除残留的PbI ₂并制备低陷阱态密度的钙钛矿薄膜。因此，钙钛矿太阳能电池的功率转换效率（PCE）从 18.36% 提高到 20.4%。在经过 MASCN 处理的器件中也观察到了增强的器件对水分的稳定性，该器件在暴露于环境空气 1780 小时后表现出 90% 的初始效率保持率。