Higha??Performance Ternary Organic Solar Cells with Morphologya??Modulated Hole Transfer and Improved Ultraviolet Photostability

摘要： Ternary bulk-heterojunction (BHJ) strategy synergistically combining the merits of fullerene and non-fullerene acceptors has been regarded as a promising approach to enhance the power conversion efficiencies (PCEs) of organic solar cells (OSCs). Herein, the fullerene derivative ICBA as the morphology regulator is incorporated into non-fullerene based PBDB-T-2F:BTP-4Cl (PM6:BTP-4Cl) system to fabricate the high-performance ternary OSCs. The amorphous ICBA prefers to homogeneously distribute in the BTP-4Cl phase to form the well-mixed acceptor domains due to their better miscibility, which distinctly reduces the exciton decay loss driven by the unfavorable phase separation and enhances BHJ morphology stability of ternary blends. The appropriate addition of ICBA induces the efficient long-range F?rster resonance energy transfer to BTP-4Cl and facilitates the ultrafast hole transfer process from BTP-4Cl to PM6, thereby contributing to charge carrier generation in the actual devices. Ultimately, the optimal ternary OSCs not only yield the average PCE higher than 16.5% but also show the superior ultraviolet photostability relative to binary control devices owing to the increased harvesting of ultraviolet photons, boosted charge transfer, more balanced charge transport and more stable nano-structural morphology. Our results provide the new insights to enable the simultaneously improved device performance and tolerance to UV light in highly efficient ternary OSCs.