Two-dimensional (2D) Ruddlesden-Popper (RP) perovskite films have attracted considerable attention for the environmentally stable perovskite solar cells. However, there is a big space for improving the film crystallinity and its crystallographic orientation to enhance the efficiency of solar cells. In addition, the assistance of anti-solvent is commonly used to obtain a better crystallinity and orientation of 2D RP perovskite films. Nevertheless, the anti-solvent method produces a lot of volatile organic compounds toxic to human health and is challenging to control. Here, we prepared 2D RP perovskite (PEA)₂(MA)₄Pb₅I₁₆ (n=5) films with the assistance of methylammonium chloride (MACl) additive via a simple one-step deposition method by avoiding anti-solvent treatment. The MACl additive is believed to induce the formation of an intermediate phase composed of perovskite crystals without annealing, which directly promotes the vertical alignment of 2D RP perovskite films on the substrate.The 2D RP films deposited on the mesoporous TiO₂ electron transport layer showed high crystallinity and preferential vertical crystallographic orientation. The resulting devices exhibited a power conversion efficiency of 9.7%, much higher than that of the devices prepared without MACl (0.66%).

二维（2D）Ruddlesden-Popper（RP）钙钛矿薄膜对环境稳定的钙钛矿太阳能电池引起了极大的关注。但是，存在用于改善膜的结晶度和其晶体学取向以提高太阳能电池的效率的大空间。另外，通常使用抗溶剂的辅助来获得更好的2D RP钙钛矿薄膜的结晶度和取向。然而，抗溶剂方法会产生许多对人体健康有毒的挥发性有机化合物，并且难以控制。在这里，我们准备了2D RP钙钛矿（PEA）₂（MA）₄ Pb ₅ I ₁₆（n = 5）借助甲基氯化铵（MACl）添加剂，通过一种简单的一步沉积方法避免了反溶剂处理，从而获得了薄膜。据信MACl添加剂无需退火即可诱导由钙钛矿晶体组成的中间相的形成，这直接促进了2D RP钙钛矿膜在基底上的垂直排列。沉积在介孔TiO ₂电子传输层上的2D RP膜显示出较高的结晶度和优先的垂直晶体学取向。所得器件表现出9.7％的功率转换效率，远高于未制备MAC1的器件的转换效率（0.66％）。