Synergistic Enhancement of Efficiency and Stability in Triple‐Cation Perovskite Solar Cells via Optimal Cadmium Sulfide Quantum Dots Incorporation

In this study, we investigate the incorporation of cadmium sulfide (CdS) quantum dots (QDs) into the active layer of triple‐cation perovskite solar cells (PSCs) to simultaneously enhance device efficiency and operational stability. A systematic optimization revealed that 0.75 wt.% CdS QDs significantly improve perovskite film crystallinity, morphology, and light absorption and effectively passivate trap states, facilitate charge extraction, and enhance carrier dynamics. Devices with 0.75 wt.% CdS QDs achieved a peak power conversion efficiency (PCE), reduced hysteresis, improved external quantum efficiency, and excellent long‐term stability, retaining ~86% of their initial PCE after 21 days of storage. Our findings underscore the potential of CdS QDs as a multifunctional additive for advancing the performance and durability of next‐generation PSCs.