Jintu Wang, Huaiying Ye, Hongjiao Li, Chongyu Mei, Jun Ling, Weishi Li and Zhiquan Shen
A series of donor-acceptor oligomer OBTThn (n=1–7) and polymer PBTTh1 and PBTTh2 composed of alternative 2,1,3-benzothiadiazole and 3-hexylthiophene have been designed and synthesized. The different orientation pattern of the side hexyl chains endows the polymers different regioregularity. It was found that the chain length of the oligomers and polymers has great impact on their photophysical, electrochemical and photovoltaic properties. Whereas, the side-chain regioregularity has less influence on their basic physical properties and photovoltaic performance.