Multifunctional AO‐245 Antioxidant Enables UV‐Resistant and High‐Efficient Perovskite Solar Cells

ABSTRACT Ultraviolet (UV) radiation greatly affects the stability of perovskite solar cells (PSCs), limiting their application in extreme environments such as plateaus and deserts. Herein, the antioxidant [triethylene glycol bis (3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl) propionate] (AO‐245) is introduced into the perovskite layer by anti‐solvent method to improve the UV stability. AO‐245 not only demonstrates UV absorption properties but also neutralizes harmful superoxide radicals () through a hydrogen atom transfer mechanism (HAT), thereby mitigating the photodegradation damage of perovskite. Additionally, the −OH group in AO‐245 can form hydrogen bonds with I ⁻ , inhibit the migration of iodide ions due to photoaging, and synergistically enhance the UV stability of the device. As a result, even after 120 h of exposure to UV light at 275 and 365 nm, the AO‐245‐modified PSCs retain more than 88% and 83% of their initial power conversion efficiency (PCE), respectively. AO‐245 additive passivates the uncoordinated Pb ²⁺ through C═O and C─O bonds, thereby enhancing the film's quality and the device's stability. Consequently, the device achieves a PCE of 19.76%, which is among the highest efficiencies observed hole transport material (HTM)‐free carbon‐based PSCs (C‐PSCs). This study provides a simple solution to improve the durability of PSCs under UV radiation, facilitating their application in extreme environments.