Revealing the Position Effect of an Alkylthio Side Chain in Phenyl-Substituted Benzodithiophene-Based Donor Polymers on the Photovoltaic Performance of Non-Fullerene Organic Solar Cells
Journal article, 2019

In this work, position effects of an alkylthio side chain were investigated by designing and synthesizing two copolymers based on a phenyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDTP) and difluorobenzotriazole (FTAZ). The polymer based on the meta-position-alkylthiolated BDTP, named m-PBDTPS-FTAZ, showed a relatively broader bandgap (2.00 vs 1.96 eV) and lower highest occupied molecular orbital (HOMO) energy level (-5.40 vs-5.32 eV) than its para-positioned structural isomeric analogue polymer (named p-PBDTPS-FTAZ), that is, m- A nd p-PBDTPS-FTAZ with the side chain structured as ethylhexyl-in the phenyl unit and hexyldecyl-in the FTAZ moiety. When blended with ITIC, m-PBDTPS-FTAZ showed a comparable crystallinity but more uniform morphology compared to that of p-PBDTPS-FTAZ. A high power conversion efficiency of 13.16% was achieved for m-PBDTPS-FTAZ:ITIC devices with a high open circuit voltage (VOC) of 0.95 V, which is higher than that of p-PBDTPS-FTAZ:ITIC devices (10.86%) with a VOC of 0.89 V. Therefore, m-BDTPS could be an effective donor unit to construct high-efficiency polymers due to its effectively decreased HOMO energy level of polymers while still maintaining good molecular stacking.

conjugated polymers

position effects

broad bandgap

side chains

polymer solar cells


W. Chen

Qingdao University

Gongyue Huang

Chinese Academy of Sciences

Xiaoming Li

Chinese Academy of Sciences

Yonghai Li

Chinese Academy of Sciences

Huan Wang

Qingdao University

H. X. Jiang

Chinese Academy of Sciences

Zhihui Zhao

Qingdao University

Donghong Yu

Sino-Danish Center for Education and Research Denmark

Aalborg University

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

R. Yang

Chinese Academy of Sciences

ACS Applied Materials & Interfaces

1944-8244 (ISSN) 1944-8252 (eISSN)

Vol. 11 36 33173-33178

Subject Categories

Polymer Chemistry





More information

Latest update