High-crystallinity fluoropolymer collaborating fluorous solvent post-treatment for efficient thick-film organic solar cells
Thick-film organic solar cells (OSCs) are indispensable for scalable manufacturing, yet they suffer from severe energy loss and complex morphology control. This study reports the synthesis of a fluoropolymer PF8 and its integration with fluorous solvent vapor annealing (FSVA) post-treatment to fabricate high-performance thick-film OSCs. The fluorination strategy and FSVA process synergistically enhance polymer crystallinity and induce an intrinsic fibrous morphology. The FSVA-treated PF8:L8BO device with a 110 nm active layer achieves a power conversion efficiency (PCE) of 18.89%. At film thicknesses of 300 nm and 500 nm, the devices retain high efficiencies of 17.54% and 15.59%, respectively. The 300-nm FSVA-treated blend films exhibit enhanced packing order and well-defined fibrillar morphology, leading to suppressed non-radiative recombination and efficient charge transport along the fiber network. This work demonstrates the potential of combining fluoropolymers with fluorous solvent-based device engineering for advanced thick-film optoelectronic applications, providing a viable pathway for scalable OSC manufacturing.