Direct C–H Arylation-Derived Donor Polymers Afford PCEs over 10% for Organic Solar Cells

Direct C–H arylation polymerization (DArP) using unfunctionalized C–H bonds as a coupling partner has emerged as a sustainable synthetic strategy toward π-functional polymers with minimized waste emissions and potentially having comparable optoelectronic performances with the polymers derived from the C–Sn bond-based Stille couplings. However, most of the reported DArP-derived π-polymers used in bulk heterojunction organic solar cells (OSC) still deliver power conversion efficiencies (PCEs) below 10%. In this work, the PBDB-T2F (i.e., PM6) polymer was synthesized, for the first time, by the tin-free DArP under optimized conditions, which affords a PCE up to 10.1% for OSC devices. Although the systematical comparison study by varied characterizations including gel permeation chromatography, UV–vis spectroscopy, BHJ devices, microscopies, and grazing incidence X-ray diffraction reveals that the DArP strategy still needs to be improved in terms of reactivity and regioselectivity compared to the Stille couplings, the preliminary yet promising results here obtained will provide the stimulus for the generalization of DArP to the atom-economic synthesis of high-performance π-polymers, and promote the integration of green chemistry with green energy.