Asymmetric Non-Fullerene Acceptor Derivatives Incorporated Ternary Organic Solar Cells

Incorporating ITIC derivatives as guest acceptors intobinary hostsystems is an effective strategy for constructing high-performanceternary organic solar cells (TOSCs). In this work, we introduced A-D-Atype ITIC derivatives PTBTT-4F (asymmetric) and PTBTP-4F (symmetric)into the PM6:BTP-BO-4F (Y6-BO) binary blend and investigated the impactsof two guest acceptors on the performance of TOSCs. Differentiateddevice performance was observed, although PTBTT-4F and PTBTP-4F presentedsimilar chemical structures and comparable absorptions. The PTBTT-4Fternary devices exhibited an improved power conversion efficiency(PCE) of 17.67% with increased open circuit (V (OC)) and current density (J (SC)), whereas the PTBTP-4F-based ternary devices yielded a relativelylower PCE of 16.34%. PTBTT-4F showed much bettercompatibility with the host acceptor BTP-BO-4F, so that they formeda well-mixed alloy phase state; more precise phase separation andincreased crystallinity were thus induced in the ternary blends, leadingto reduced molecular recombination and improved charge mobilities,which contributed to improved fill factors of the ternary devices.In addition, the optimized PTBTT-4F devices exhibited good performancetolerance of the photoactive layer thickness, as they even delivereda PCE of 15.25% when the active layer was as thickas up to & SIM;300 nm.