摘要： The photovoltaic performance of organic solar cells has been rapidly improved. However, in actual production and application, there are still many challenges for organic photovoltaic devices and one of the important strategies to facilitate industrialization is reducing material price. The BDT-BDD binary copolymer donor material has good photovoltaic performance. However, the high price of benzodithiophenedione (BDD) monomer limits its industrialization. In contrast, benzotriazole (BTA) monomers with lower price possess an enormous potential to solve this problem. Therefore, in this paper, it is reported that the synthesis of ternary copolymerization by adding BTA units into BDT-BDD copolymer with two different acceptor units. Through research, it is found that such a strategy can effectively reduce the price of BDT-BDD polymer, and increasing the content of BTA units in polymer to reduce the content of expensive BDD units can still retain the excellent photovoltaic properties of BDT-BDD polymer. When only 20 mol % of BDD units remained, the bulk-heterojunction (BHJ) structure with the synthesized donor polymer and acceptor ITIC can achieve an open circuit voltage of 0.913 V with a short circuit current of 16.87 mA cm-2 and 9.12% maximum photoelectric conversion efficiency, which is much cheaper than BDT-BDD polymer, in terms of structural units. Therefore, the results show that the addition of BTA can effectively reduce the material cost (vs. BDD only) while retaining the good photovoltaic properties of the material, and has a certain guiding effect on the commercialization of OSC.