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

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.