Regioisomeric Non-Fullerene Acceptors Containing Fluorobenzo[c][1,2,5]thiadiazole Unit for Polymer Solar Cells

Wenkai Zhong; Baobing Fan; Jing Cui; Lei Ying; Feng Liu; Junbiao Peng; Fei Huang; Yong Cao; Guillermo C Bazan

doi:10.1021/acsami.7b12902

Regioisomeric Non-Fullerene Acceptors Containing Fluorobenzo[c][1,2,5]thiadiazole Unit for Polymer Solar Cells

ACS Appl Mater Interfaces. 2017 Oct 25;9(42):37087-37093. doi: 10.1021/acsami.7b12902. Epub 2017 Oct 16.

Authors

Wenkai Zhong¹, Baobing Fan¹, Jing Cui², Lei Ying¹, Feng Liu³, Junbiao Peng^{1

4}, Fei Huang¹, Yong Cao¹, Guillermo C Bazan^{1

4

5}

Affiliations

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, P. R. China.
² Sinopec Shanghai Research Institute of Petrochemical Technology , Shanghai, 201208, China.
³ Department of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai, 200240, P. R. China.
⁴ MOE International Collaborative Laboratory for Advanced Functional Materials, South China University of Technology , Guangzhou 510640, P. R. China.
⁵ Department of Chemistry and Biochemistry, Center for Polymers and Organic Solids, University of California , Santa Barbra, California 93106, United States.

PMID: 28985459
DOI: 10.1021/acsami.7b12902

Abstract

We designed and synthesized two isomeric nonfullerene acceptors, IFBR-p and IFBR-d. These molecular semiconductors contain indacenodithiophene (IDT) as the central unit, adjacent asymmetric 5-fluorobenzo[c][1,2,5]thiadiazole units, and are flanked with rhodanine as the peripheral units. The orientation of the two fluorine atoms (proximal, p, or distal, d), relative to IDT impacts most severely the film morphologies when blended with the electron-donating polymer PTzBI. Polymer solar cells based on PTzBI:IFBR-p give rise to a power conversion efficiency (7.3 ± 0.2%) that is higher than what is achieved with PTzBI:IFBR-d (5.2 ± 0.1%). This difference is attributed to the lower tendency for (over)crystallization by IFBR-p and the resulting more favorable morphology of the photoactive layer. These results highlight the subtle impact of substitution regiochemistry on the properties of nonfullerene acceptors through modulation of their self-assembly tendencies.

Keywords: acceptor; fluorobenzo[c][1,2,5]thiadiazole; nonfullerene; polymer solar cells; regiochemistry.