Power conversion efficiency (PCE) and stability are two important properties of perovskite solar cells (PSCs). Particularly, defects in the perovskite films could cause the generation of trap states, thereby increasing the nonradiative recombination. To address this issue, suitable dopants can be incorporated to react with non-bonded atoms or surface dangling bonds to passivate the defects. Herein, we introduced TiI₄ into CH₃NH₃PbI₃ (MAPbI₃) film and obtained a dense and uniform morphology with large crystal grains and low defect density. The champion cell based on 0.5% TiI₄-doped MAPbI₃ achieved a PCE as high as 20.55%, which is superior to those based on pristine MAPbI₃ (17.64%). Moreover, the optimal solar cell showed remarkable stability without encapsulation. It retained 88.03% of its initial PCE after 300 h of storage in ambient. This work demonstrates TiI₄ as a new and effective passivator for MAPbI₃ film.

功率转换效率（PCE）和稳定性是钙钛矿太阳能电池（PSC）的两个重要属性。特别地，钙钛矿膜中的缺陷可能导致陷阱态的产生，从而增加了非辐射复合。为了解决这个问题，可以掺入合适的掺杂剂以与未键合的原子或表面悬挂键反应以钝化缺陷。在本文中，我们介绍了TII ₄到CH ₃ NH ₃碘化铅₃（MAPbI ₃）膜和得到致密且均匀的形态，大晶粒和低缺陷密度。基于0.5％TiI ₄掺杂的MAPbI ₃的冠军细胞实现了高达20.55％的PCE，优于基于原始MAPbI _3的PCE （17.64％）。此外，最佳太阳能电池无需封装即可显示出显着的稳定性。在环境中存储300小时后，它保留了其初始PCE的88.03％。这项工作证明了TiI ₄是MAPbI ₃膜的新型有效钝化剂。