High‐Performance Perovskite Solar Cells with Excellent Humidity and Thermo‐Stability via Fluorinated Perylenediimide

The notoriously poor stability of perovskite solar cells is a crucial issue restricting commercial applications. Here, a fluorinated perylenediimide (F‐PDI) is first introduced into perovskite film to enhance the device's photovoltaic performance, as well as thermal and moisture stability simultaneously. The conductive F‐PDI molecules filling at grain boundaries (GBs) and surface of perovskite film can passivate defects and promote charge transport through GBs due to the chelation between carbonyl of F‐PDI and noncoordinating lead. Furthermore, an effective multiple hydrophobic structure is formed to protect perovskite film from moisture erosion. As a result, the F‐PDI‐incorporated devices based on MAPbI3 and Cs0.05 (FA0.83MA0.17)0.95 Pb (Br0.17I0.83)3 absorber achieve champion efficiencies of 18.28% and 19.26%, respectively. Over 80% of the initial efficiency is maintained after exposure in air for 30 days with a relative humidity (RH) of 50%. In addition, the strong hydrogen bonding of F···H‐N can immobilize methylamine ion (MA+) and thus enhances the thermal stability of device, remaining nearly 70% of the initial value after thermal treatment (100 °C) for 24 h at 50% RH condition. Fluorinated perylenediimide (F‐PDI) is first introduced to optimize photovoltaic performance and stability of perovskite solar cells. Conductive F‐PDI effectively passivates defects and promotes charge transfer. The hydrophobicity of F‐PDI preventing moisture penetration as well as the strong hydrogen bonding immobilizing methylamine ions, thereby, endow excellent moisture and thermal stability with nearly 70% efficiency retention after thermal treatment at 100 °C.