Multifunctional Fluorinated Self-Polymerizable Additive Improves the Performance of Perovskite Photovoltaics

High Resolution Image Download MS PowerPoint Slide The incorporation of self-polymerizable additives is an effective strategy to improve both efficiency and stability of perovskite solar cells (PSCs), yet the structure-performance relationship remains unclear. Here, two self-polymerizable additives, 2,2,3,3,3-pentafluoropropyl acrylate (PFPA) and n -propyl acrylate (NPA), are systematically investigated. Both additives undergo in situ thermal polymerization during perovskite annealing. The fluorinated PFPA exhibits strong interactions with undercoordinated Pb 2+, enabling effective crystallization regulation and defect passivation. Polymerized PFPA preferentially accumulates at the perovskite top surface, forming a hydrophobic dipole layer that enhances charge extraction and interfacial stability. As a result, PSCs with polymerized PFPA achieve a champion power conversion efficiency (PCE) of 26.01% and retain 90.0% of the initial efficiency after 840 h at 85 °C in nitrogen and 95.1% after 1000 h under maximum power point tracking conditions. Furthermore, minimodules with an active area of 14 cm 2 deliver a PCE of 21.66%.