Side-Chain-Promoted Benzodithiophene-based Conjugated Polymers toward Striking Enhancement of Photovoltaic Properties for Polymer Solar Cells

Weichao Chen; Gongyue Huang; Xiaoming Li; Huan Wang; Yonghai Li; Huanxiang Jiang; Nan Zheng; Renqiang Yang

doi:10.1021/acsami.8b16554

Side-Chain-Promoted Benzodithiophene-based Conjugated Polymers toward Striking Enhancement of Photovoltaic Properties for Polymer Solar Cells

ACS Appl Mater Interfaces. 2018 Dec 12;10(49):42747-42755. doi: 10.1021/acsami.8b16554. Epub 2018 Nov 30.

Authors

Weichao Chen^{1

2}, Gongyue Huang², Xiaoming Li², Huan Wang¹, Yonghai Li², Huanxiang Jiang², Nan Zheng³, Renqiang Yang²

Affiliations

¹ College of Textiles & Clothing, State Key Laboratory of Bio-fibers and Eco-textiles, Collaborative Innovation Center for Eco-textiles of Shandong Province , Qingdao University , Qingdao 266071 , China.
² CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology , Chinese Academy of Sciences , Qingdao 266101 , China.
³ State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China.

PMID: 30457314
DOI: 10.1021/acsami.8b16554

Abstract

In this work, we have reported a highly efficient photovoltaic material, PBDTTz-SBP, by fine-tuning the side chains of the benzodithiophene (BDT) unit. With the replacement of alkoxy chains with alkylthio chains, a large increase in power conversion efficiency (PCE) was realized. Non-fullerene polymer solar cells (PSCs) without any post-treatment generate an optimal PCE of up to 12.09%, with a high V_OC of 0.914 V, J_SC of 18.52 mA cm^-2, and fill factor of 71.43%. Notably, the efficiency of a PBDTTz-SBP-based solar cell was about 1.31-fold of the PCE (9.20%) of its counterpart based on the polymer, PBDTTz-BP, with alkoxy chains, indicating the striking modulation effect of side-chain engineering. Although V_OC and J_SC were lower than those of non-fullerene devices, the PSCs with PC₇₁BM as the acceptor exhibited a fairly high fill factor of up to 76.69%, affording a moderate PCE. Our work reported a highly efficient polymer solar cell with a PCE of 12.09% and clearly demonstrated the great tuning effect of alkylthio chains on photovoltaic performance.

Keywords: benzodithiophene; open-circuit voltage; polymer solar cells; side chain.