The performance of perovskite solar cells (PSCs) is extremely dependent on morphology and crystallinity of perovskite film. One of the most effective methods to achieve high performance perovskite solar cells has been to introduce additives that serve as dopants, crystallization or passivation agents. Herein a facile strategy by introducing methylammonium chloride (MACl) and polar solvent N,N-Dimethylformamide (DMF) as co-additives in two-step sequential method is proposed to realize high quality perovskite film. It is demonstrated that DMF facilitates methylammonium iodide (MAI) penetrating easily into PbI₂ layer to form highly crystalized perovskite film with uniform morphology which is essential to achieve high V_OC. While MACl induces MAPbI₃ to crystallize in a pure α-phase and suppress non-photovoltaic phase, which guarantees high FF. Pure α-phase perovskite film with uniform morphology can be achieved by adopting MACl and DMF together and the corresponding solar cell illustrates a power conversion efficiency (PCE) of 19.02% with substantially promoted durability. Moreover, A V_OC as high as 1.181 V is succeeded for MAPbI₃ based solar cell benefiting from the synergistic effect.

钙钛矿太阳能电池（PSC）的性能在很大程度上取决于钙钛矿薄膜的形态和结晶度。实现高性能钙钛矿太阳能电池的最有效方法之一是引入用作掺杂剂，结晶或钝化剂的添加剂。在本文中，提出了通过两步顺序方法引入甲基氯化铵（MACl）和极性溶剂N，N-二甲基甲酰胺（DMF）作为助添加剂的简便策略，以实现高质量的钙钛矿薄膜。事实证明，DMF有助于甲基碘化碘（MAI）易于渗透到PbI ₂层中，形成具有均匀形态的高结晶钙钛矿薄膜，这对于获得高V _OC是必不可少的。MACl诱导MAPbI ₃结晶为纯α相并抑制非光伏相，从而确保了高FF。可以通过同时使用MACl和DMF来获得具有均匀形貌的纯α相钙钛矿薄膜，相应的太阳能电池的功率转换效率（PCE）为19.02％，并且耐久性得到大大提高。此外，受益于协同效应，基于MAPbI ₃的太阳能电池成功获得了高达1.181 V的AV _OC。