Two wins in one move of additive engineering: Achieving crystallization regulation and multi-site defect passivation for high-performance perovskite solar cells

Additive engineering has been widely employed to address defect-related issues in perovskite solar cells (PSCs). Due to the diversity of defect types in perovskite films, it is desired to passivated different defects with only one additive kind - two wins with one move. In this study, we introduce methyldiphenylsulfonium tetrafluoroborate (MDPS-TFB) as a multifunctional additive into the perovskite precursor solution. The MDPS group interacts with Pb and I elements, and BF₄ group forms hydrogen bonds with FA group in the perovskite film, achieving efficient defect passivation. Moreover, these interactions effectively modulate the crystallization process, suppress phase decomposition, reduce non-radiative recombination, and thereby significantly enhance device performance. The PSCs with MDPS-TFB demonstrate an improvement in power conversion efficiency (PCE) from 24.61 % to 25.63 %, and enhanced stability under 50–70 % relative humidity (RH). The findings provide a new insight into perovskite additive design and advance the development of highly efficient and stable perovskite optoelectronic devices.