Natural Green Antioxidant Proanthocyanidin Enhances the UV/Oxidation Resistance of Perovskite Solar Cells Through Buried Interface Modification Strategy

ABSTRACT As the efficiency of perovskite solar cells (PSCs) continues to rise, extending their operational stability outdoors has become critical for commercial adoption. However, in outdoor high‐energy ultraviolet (UV) and strong oxidizing environments, it is easy to cause lattice distortion of perovskite and accelerate the aging of photovoltaic modules. Herein, to address UV‐induced lattice distortion and oxidation in perovskite layers, we introduce natural grape seed proanthocyanidin (OPC) at the TiO ₂ /perovskite buried interface. OPC, which serves as a bridge, forms a stable interface bonding network through hydrogen bonding between its multiple phenolic hydroxyl groups, and the TiO ₂ surface is covered with hydroxyl groups (─OH), reducing the density of defect states on the ETL surface, suppressing carrier recombination, and thereby improving carrier mobility and extraction efficiency. Meanwhile, the C═C and ─OH functional groups of OPC molecules bind with undercoordinated Pb ²⁺ ions to inhibit nonradiative recombination, promote the perovskite crystal growth, and form excellent perovskite films. With the OPC “antioxidation‐passivation‐UV protection” trinity buried interface engineering strategy, the PCE of the ingeniously designed PSCs upgraded from 22.91% to 24.79%. In addition, the modification of OPC effectively blocks the erosion of the perovskite crystal phase by ultraviolet radiation, providing excellent UV/oxidation resistance stability.