High‐Performance Perovskite Solar Cells with Low Open‐Circuit Voltage Loss and Excellent Stability after P‐f‐peai Posttreatment

Photoelectric properties of perovskite solar cells (PSCs) are closely linked to defects on the surface of perovskite in the preparation process, which have a significant impact on the open‐circuit voltage ( V OC ) of devices. It is necessary for high‐performance PSCs to suppress the non‐radiative recombination at the interface and improve the charge transfer. Herein, phenylethyl ammonium iodide containing fluorine (p‐F‐PEAI) is utilized to treat the perovskite film, which can optimize the energy‐level alignment between perovskite layer and hole‐transport layer to promote charge transfer and reduce non‐radiative recombination by passivating interface defects and inhibiting the generation of Pb 0 . The introduction of fluoride can enhance the electropositivity of −NH 3 + to obtain excellent passivation and moisture resistance. The p‐F‐PEAI‐modified PSCs achieve a superior power conversion efficiency of 22.56% with remarkable V OC (1.20 V) and maintain 96% of the initial optimal value after 1000 h without encapsulation.