Fused electron acceptor units play a significant role in donor materials for organic solar cells (OSCs). This paper introduces the fused dithieno[3′,2':3,4;2″,3'':5,6]benzo[1,2-c][1,2,5]thiadiazole (DTBT) units into the benzo[1,2-b:4,5-b']dithiophene-benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDT-BDD) backbones to synthesize terpolymers. The photovoltaic performance of the terpolymers is investigated by adding the π-bridges on both sides of the DTBT. For Y6-based OSCs, the devices based on DTBT terpolymers without additional π-bridges can obtain high open-circuit voltage (V_OC) but low fill factor (FF). On the contrary, DTBT terpolymers with 3-octylthiophene π-bridges significantly enhance the FF but decrease the V_OC in devices. By investigating terpolymers' photovoltaic and quantum chemistry properties, we find that the presence of π-bridge structures on both sides of the DTBT unit can effectively promote carrier collection and reduce the bimolecular recombination in the devices. However, its reduced charge-transfer state energy level results in high voltage losses. Therefore, the design of DTBT terpolymers for how to balance the voltage loss due to π-bridges brought to the optimization of polymer conformation and charge excitation and conversion will become an important subject.

熔融电子受体单元在有机太阳能电池 (OSC) 的供体材料中发挥着重要作用。本文将稠合二噻吩并[3',2':3,4;2",3'':5,6]苯并[1,2-c][1,2,5]噻二唑(DTBT)单元引入苯并[1,2-b:4,5-b']二噻吩-苯并[1,2-c:4,5-c']二噻吩-4,8-​​二酮（BDT-BDD）主链合成三元共聚物。通过在 DTBT 两侧添加 π 桥来研究三元共聚物的光伏性能。对于基于 Y6 的 OSC，基于 DTBT 三元共聚物的器件无需额外的 π 桥即可获得高开路电压 (V _OC ) 但填充因子 (FF) 低。相反，具有 3-辛基噻吩 π-桥的 DTBT 三元共聚物显着增强了 FF 但降低了 V _OC在设备中。通过研究三元共聚物的光伏和量子化学性质，我们发现DTBT单元两侧存在π桥结构可以有效促进载流子收集并减少器件中的双分子复合。然而，其降低的电荷转移态能级会导致高电压损耗。因此，DTBT三元共聚物的设计如何平衡π桥带来的电压损失，从而优化聚合物构象和电荷激发与转化将成为重要课题。