Synergistic passivation of defects with a multifunctional additive for perovskite solar cells

The presence of crystal defects in perovskite films significantly hinders the high efficiency and stability of perovskite solar cells. This study combines theoretical calculations and experimental characterizations to reveal the multifunctional synergistic passivation effect of sodium 2,4,5-trifluorobenzoate (STFB). Incorporating STFB resulted in high-quality perovskite films with increased grain sizes and decreased defect densities. Meanwhile, the optimized energy level alignment facilitates carrier extraction and transport, effectively increasing the open-circuit voltage (VOC). Ultimately, the STFB-modified devices achieved a 12.22% relative enhancement in power conversion efficiency (PCE) compared to the control devices. Additionally, the STFB-modified unencapsulated devices exhibit excellent long-term stability, maintaining 92.01% of the highest PCE after 1440 h. This study not only provides insights into the synergistic passivation of STFB but also suggests potential pathways for applying multifunctional organic molecules in photovoltaic device optimization.