Ultraviolet‐Controlled Radical Dopants: Suppressing Unpredictable Oxidation and Lithium Migration in Perovskite Solar Cells

Abstract Perovskite solar cells (PSCs) have achieved parity in efficiency with silicon‐based solar cells. This dependency introduces stability challenges and complicates device fabrication due to the traditional air‐oxidation doping process, which is time‐consuming, unpredictable, and requires continuous monitoring of device variability. Here, we propose two triphenyl sulfonium (TPS) salts as UV‐light‐triggered radical‐generating dopants for 2,2′,7,7′‐tetrakis [ N,N ‐di(4‐methoxyphenyl) amino]‐9,9′‐spirobifluorene(spiro‐OMeTAD). These dopants eliminate the need for air‐based oxidation, thereby simplifying fabrication while enhancing the electrical properties of spiro‐OMeTAD through efficient p‐type doping. Using this approach, we achieved a champion power conversion efficiency of 25.18%, surpassing the performance of traditional doping methods. Notably, PSCs incorporating TPS dopants and cost‐effective silver top‐electrodes demonstrated exceptional stability under various operational conditions. This work presents a scalable, cost‐effective doping strategy that addresses critical stability‐efficiency trade‐offs in PSCs, positioning them as viable contenders for commercial renewable energy applications.