We synthesized uniform FA_xMA_1-xPbI₃ perovskite films with a single α phase by a two-step process combined with a dynamically dispensed spin-coating technique. It uses the continuous dropping of precursor solutions with a constant CH₃NH₃I (MAI)/HC(NH₂)₂I (FAI) concentration enabling the kinetically controlled grain growth. Dynamic coating cycles are also changed to facilitate a cation-exchange process, control the degree of the mutual inter-mixing between formamidinium lead triiodide (FAPbI₃) and methylammonium lead triiodide (MAPbI₃) and examine the formation process and properties of the mixed perovskite films formed under the excess MA/FA cation environment, which has not been clarified so far. Notably, without additional solvent washing steps, FA_xMA_1-xPbI₃ films are adjustable in composition, pinhole-free, and have various grain sizes depending on the coating cycles. Perovskite solar cells (PSCs) synthesized from FA_xMA_1-xPbI₃ films with two cycles of the dynamic spin coating have achieved a maximum power conversion efficiency (PCE) of 18.50% with an average PCE of 17.06 ± 0.42%, which shows much-improved performance as well as reproducibility compared with 14.79 ± 1.82% obtained from the conventional static spin-coating method. In addition, we first found mixed FA_xMA_1-xPbI₃ perovskites synthesized under an excess cation environment containing local stoichiometric inhomogeneities as well as excess residual cations (C˭N and NH₃⁺) acting as recombination traps, which is supported by the calculation of trap densities.

我们通过两步工艺与动态分配旋涂技术相结合，合成了具有单个α相的均相FA _x MA _{1- x} PbI ₃钙钛矿薄膜。它使用恒定浓度的CH ₃ NH ₃ I（MAI）/ HC（NH ₂）₂ I（FAI）浓度连续滴加前体溶液，从而实现了动力学控制的晶粒长大。动态涂料周期也被改变，以促进阳离子交换过程中，控制所述相互间混合甲脒三碘化铅（FAPbI之间的程度₃）和甲基铵三碘化铅（MAPbI ₃）并检查在过量的MA / FA阳离子环境下形成的钙钛矿混合膜的形成过程和性能，目前尚未弄清。值得注意的是，无需额外的溶剂洗涤步骤，FA _x MA _{1- x} PbI ₃膜的成分即可调节，无针孔，并且根据涂布周期而具有不同的晶粒尺寸。由FA _x MA _{1- x} PbI ₃合成的钙钛矿太阳能电池（PSC）具有两个动态旋涂循环的薄膜已经实现了18.50％的最大功率转换效率（PCE），平均PCE为17.06±0.42％，与之相比，从14.79±1.82％获得的性能和可重复性大大提高。传统的静态旋涂方法。此外，我们首先发现在过量阳离子环境下合成的FA _x MA _{1- x} PbI ₃钙钛矿混合物，该环境包含局部化学计量不均匀性以及充当重组陷阱的过量残留阳离子（C˭N和NH ₃ ⁺），这得到了以下方面的支持陷阱密度的计算。