Mitigation energy loss with fullerene derivatives doping regulation for efficient tin perovskite solar cells

Halide tin-based perovskites have gradually emerged as one of the most competitive candidates for lead-free perovskite photovoltaics owing to their superior optoelectronic properties and low toxicity. However, substantial energy losses limit the device performance of tin-based perovskite solar cells (TPSCs). Herein, we developed a regulation doping strategy that effectively reduces device energy loss by introducing perfluoroalkyl and pyridine-functionalized fullerene derivatives (C60-PyF15) as a regulating intermediary. This strategy successfully optimizes the energy level alignment, accelerates carrier extraction at the perovskite/transport layer interface, and reduces non-radiative recombination. Additionally, it mitigates the oxidation of Sn2+, increases the crystallinity, and passivates the perovskite by suppressing its intrinsic defects. Consequently, the open-circuit voltage (VOC) of the TPSCs is markedly improved, leading to a champion power conversion efficiency of 13.72%, corresponding to a relative improvement of over 20% compared to the control device (11.41%). This work offers a novel strategy to address energy loss issues, providing valuable insights for fabricating more efficient and stable TPSCs.