Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (8): 1635-1643.doi: 10.3866/PKU.WHXB201704244

Special Issue: Special Issue for Highly Cited Researchers

• ARTICLE • Previous Articles     Next Articles

Design, Synthesis and Photovoltaic Performance of Novel Conjugated Polymers Based on Difluorobenzothiadiazole and 2, 3-Bis[thiophen-2-yl]acrylonitrile

Jiang-Bo ZHENG,Zhi-Ming CHEN,Zhi-Cheng HU,Jie ZHANG*(),Fei HUANG*()   

  • Received:2017-03-15 Published:2017-06-14
  • Contact: Jie ZHANG,Fei HUANG;
  • Supported by:
    the National Natural Science Foundation of China(51403070);the National Natural Science Foundation of China(21520102006)


In this study, two novel difluorobenzothiadiazole (DFBT)-based polymeric donors, poly[(5, 6-difluoro-benzo[c][1, 2, 5]thiadiazol-4, 7-yl)-alt-((E)-2, 3-bis(3'-(2-octyldodecyl)-(2, 2'-bithiophen)-5, 5'-yl) acrylonitrile)] (DFBT812) and poly[(5, 6-difluoro-benzo[c][1, 2, 5]thiadiazol-4, 7-yl)-alt-((E)-2, 3-bis(3'-(2-decyltetradecyl)-(2, 2'-bithiophen)-5, 5'-yl) acrylonitrile)] (DFBT1014), possessing 2-octyldodecyl and 2-decyltetradecyl side chains, respectively, were designed, synthesized, and applied for polymer solar cells. Alkyl chains of 2-octyldodecyl and 2-decyltetradecyl were incorporated into the polymer to tune the solubility and crystallization of the polymers and morphology of the blend films. Morphological study showed that the blend film of DFBT812 with PC61BM presented much better phase separation domain, which is beneficial for charge transport and collection of charge carriers in the blend film. Photovoltaic devices based on DFBT812 exhibited a power conversion efficiency (PCE) of 6.25%, outperforming those based on DFBT1014. Moreover, DFBT812-based photovoltaic devices exhibited a PCE over 6% even when the thickness of the active layer was 220 nm.

Key words: Difluorobenzothiadiazole, 2, 3-Bis[thiophen-2-yl]acrylonitrile, Side chain engineering, Polymer donor, Polymer solar cells