Enhancing Ultraviolet Stability and Performance of Wide Bandgap Perovskite Solar Cells Through Ultraviolet Light‐Absorbing Passivator

Abstract Ultraviolet light (UV) has caused tremendous damage to perovskite solar cells (PSCs), degrading the perovskite and shortening their lifetime. Defects act as non‐radiative recombination sites, accelerate the degradation process, reduce the efficiency of the device and weaken the stability of solar cell. In this work, to realize efficient and stable p–i–n wide bandgap solar cells under UV, a synergetic strategy utilizing UV light‐absorbing passivator, (Trifluoroacetyl) benzotriazole (TFABI), enhance UV photostability and regulate the defect passivation is proposed. By using TFABI, the degradation of the perovskite absorption layer under UV light is suppressed, spectral response is enhanced and the Pb vacancy defects are passivated. As a result, the target device achieves an efficiency of 21.54%, exhibiting excellent long‐term stability under 365 nm UV irradiation. After 60 h of irradiation, it retains 85% of its initial value (60 mW cm−2, RH 25–30%, 25 °C).