Three new donor–acceptor (D–A) copolymers based on benzodithiophene (BDT) with alkylthiolated aromatic rings furan, thiophene, and benzene and 5,6-difluoro-4,7-bis(4-(2-octyldodecyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT) units, namely PBDTFS-DTBT, PBDTTS-DTBT, and PBDTPS-DTBT, respectively, were synthesized and applied in solution-processed fullerene type organic solar cells (OSCs). The target polymers were systematically investigated by thermogravimetric analysis (TGA), ultraviolet-visible (UV–vis) absorption spectra, cyclic voltammetry (CV), density functional theory (DFT) and photovoltaic measurements. The experimental results imply that the electron push-pull effect and torsion angles between the conjugated side hetero-aromatic rings and BDT core play a key role in tuning the optical absorption bands, molecular energy levels, hole mobilities, and morphology of the corresponding polymers. The OSCs based on PBDTTS-DTBT and [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) show the highest power conversion efficiency (PCE) of 7.80% among the three polymeric analogues, with an open-circuit voltage (V_oc) of 0.92 V, a short-circuit current density (J_sc) of 11.95 mA cm⁻² and fill factor (FF) of 70.76%. Hence, the results in this work indicate that the photovoltaic properties of the BDT-BT-based polymers can be effectively modulated by introducing conjugated alkylthiolated hetero-aromatic rings with the varied electron donating ability and steric hindrance.

三种新的基于苯并二噻吩（BDT），烷基硫醇化的芳环呋喃，噻吩和苯以及5,6-二氟-4,7-双（4-（2-辛基十二烷基）噻吩-2的供体-受体（DA）共聚物-基）苯并[c] [1,2,5]噻二唑（DTBT）单元，即PBDT F S-DTBT，PBDT T S-DTBT和PBDT P分别合成了S-DTBT，并将其应用于溶液处理的富勒烯型有机太阳能电池（OSC）。通过热重分析（TGA），紫外-可见（UV-vis）吸收光谱，循环伏安法（CV），密度泛函理论（DFT）和光伏测量系统地研究了目标聚合物。实验结果表明，共轭侧杂芳环和BDT核之间的电子推挽效应和扭转角在调节相应聚合物的光吸收带，分子能级，空穴迁移率和形态方面起着关键作用。基于PBDT T S-DTBT和[6,6]-苯基-C _71-丁酸甲酯（PC ₇₁BM）在三种聚合类似物中显示出7.80％的最高功率转换效率（PCE），开路电压（V _oc）为0.92 V，短路电流密度（J _sc）为11.95 mA cm ^-2填充因子（FF）为70.76％。因此，这项工作的结果表明，通过引入具有不同供电子能力和空间位阻的共轭烷基硫醇化杂芳环，可以有效地调节BDT-BT基聚合物的光电性能。