Chlorination is often adopted in the synthesis of donor materials considering the obvious improvement on efficiency of organic photovoltaic (OPV) device. Thus the chlorination effect was firstly probed based on density functional theory (DFT) calculation, which shows that the chlorinated benzothiadiazole connected with two thiophene rings (BTClTT) fragment although has larger optical bandgap and relatively blue-shifted spectrum, its deeper frontier molecular orbital (FMO) energy level, larger charge transfer distance (D_CT) and much more transferred charges (C_T), obvious negative natural population analysis (NPA) charges, larger twisted dihedral angles and smaller value of BLA indicate its favorable properties for the application in OPVs. Then, we designed a series of donor materials 2–7 adopting two strategies based on the experimental polymer 1 which contains BTClTT fragment. The calculated physical parameters characterizing OPV performance such as open-circuit voltage (V_OC) and absorption-properties manifest that the design through side chains modifications for 2–5 may have slight influence on their cell performance while the backbone replacements for 6 and 7 exhibit prominent enhancement whether on V_OC and photon-absorption property or on the charge separation ability. Therefore, our calculations suggest feasible strategies of designing donor materials for the chlorinated BT-based donor materials in OPVs. We hope our work can provide some guidelines for the future study on chlorinated donor materials.

考虑到有机光伏（OPV）器件效率的显着提高，通常在供体材料的合成中采用氯化法。因此，首先基于密度泛函理论（DFT）计算来探讨氯化作用，表明氯化苯并噻二唑与两个噻吩环（BTClTT）片段连接，尽管具有较大的光学带隙和相对蓝移的光谱，但其较深的前沿分子轨道FMO）能级，更大的电荷转移距离（D _CT）和更多的转移电荷（C _T），明显的负自然种群分析（NPA）电荷，较大的扭曲二面角和较小的BLA值，表明其在OPV中的应用具有良好的性能。然后，我们设计了一系列供体材料的2 - 7采用基于实验聚合物两种策略1包含BTClTT片段。计算出的表征OPV性能的物理参数，例如开路电压（V _OC）和吸收特性表明，通过对2 – 5进行侧链修饰的设计可能会对它们的电池性能产生轻微影响，而对于6和7的骨架进行替代表现出显着的增强是否在V _OC和光子吸收特性或电荷分离能力。因此，我们的计算结果提出了为OPV中的氯化BT基供体材料设计供体材料的可行策略。我们希望我们的工作可以为将来的氯化供体材料研究提供一些指导。