Thermal‐Triggered Sustainable Defect Passivation for Stable Inverted Perovskite Solar Cells

The defect is of great importance for perovskite solar cells (PSCs). During device aging, the already well‐passivated perovskite can still generate new defects. Traditional passivating approaches are unable to well passivate these newly generated defects, thus affecting device performance. Herein, a thermal‐triggered sustainable defect passivation strategy is proposed by employing a heat‐induced molten passivator of perfluorobutylsulphonamide (PBSA). PBSA will change to liquid after heat treatment, flowing to the generation sites of new defects and passivate them, thus inducing degraded efficiency recover and enhancing device stability. Resulting PSCs with PBSA exhibit high efficiency of 24.34% with good stability, retaining >90% of initial efficiency after ultraviolet aging for 500 h.