Ternary structure is an important design strategy to obtain high-efficiency non-fullerene organic photovoltaics (OPVs). However, the role of the third component to the standard binary system is still unclear. Here, a wide-bandgap small-molecule acceptor, denoted IDT-T, is synthesized and used together with a wide-bandgap donor polymer, PBDB-T, and a low-bandgap acceptor, ITIC, for fullerene-free ternary solar cells. The ternary cell features an enhanced power conversion efficiency (PCE) up to 12.2%, together with improved photocurrent density, open-circuit voltage (V_OC), and fill factor. Studies of the thin films indicate that IDT-T functions as an energy-level mediator, a fluorescence resonance energy-transfer donor, an electron acceptor, and a crystallization modulator in the blend, which contribute synergistically in the ternary blend to deliver a higher V_OC, more efficient exciton generation, suppressed bimolecular charge recombination and enhanced charge transport, and an overall high photovoltaic performance.

三元结构是获得高效非富勒烯有机光伏（OPV）的重要设计策略。但是，第三部分在标准二进制系统中的作用仍然不清楚。此处，合成了IDT-T的宽带隙小分子受体，并与宽带隙供体聚合物PBDB-T和低带隙受体ITIC一起用于无富勒烯三元太阳能电池。三元电池具有高达12.2％的增强的功率转换效率（PCE），以及改进的光电流密度，开路电压（V _OC）和填充因子。对薄膜的研究表明，IDT-T在共混物中起能级介体，荧光共振能量转移供体，电子受体和结晶调节剂的作用，它们在三元共混物中协同作用以提供更高的V _OC，更有效的激子产生，抑制了双分子电荷的重组，增强了电荷的传输，总体上具有较高的光伏性能。