Heteroheptacene-based acceptors with thieno[3 , 2- b]pyrrole yield high-performance polymer solar cells

Zhenghui Luo; Ruijie Ma; Jianwei Yu; Heng Liu; Tao Liu; Fan Ni; Jiahao Hu; Yang Zou; Anping Zeng; Chun-Jen Su; U-Ser Jeng; Xinhui Lu; Feng Gao; Chuluo Yang; He Yan

doi:10.1093/nsr/nwac076

Heteroheptacene-based acceptors with thieno[3 , 2- b]pyrrole yield high-performance polymer solar cells

Natl Sci Rev. 2022 Apr 27;9(7):nwac076. doi: 10.1093/nsr/nwac076. eCollection 2022 Jul.

Authors

Zhenghui Luo¹, Ruijie Ma², Jianwei Yu³, Heng Liu⁴, Tao Liu², Fan Ni¹, Jiahao Hu¹, Yang Zou¹, Anping Zeng², Chun-Jen Su⁵, U-Ser Jeng⁵, Xinhui Lu⁴, Feng Gao³, Chuluo Yang¹, He Yan²

Affiliations

¹ Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
² Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology (HKUST), Hong Kong, China.
³ Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-58183, Sweden.
⁴ Department of Physics, Chinese University of Hong Kong, Hong Kong, China.
⁵ Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, China.

Abstract

Rationally utilizing and developing synthetic units is of particular significance for the design of high-performance non-fullerene small-molecule acceptors (SMAs). Here, a thieno[3,2-b]pyrrole synthetic unit was employed to develop a set of SMAs (ThPy1, ThPy2, ThPy3 and ThPy4) by changing the number or the position of the pyrrole ring in the central core based on a standard SMA of IT-4Cl, compared to which the four thieno[3,2-b]pyrrole-based acceptors exhibit bathochromic absorption and upshifted frontier orbital energy level due to the strong electron-donating ability of pyrrole. As a result, the polymer solar cells (PSCs) of the four thieno[3,2-b]pyrrole-based acceptors yield higher open-circuit voltage and lower energy loss relative to those of the IT-4Cl-based device. What is more, the ThPy3-based device achieves a power conversion efficiency (PCE) (15.3%) and an outstanding fill factor (FF) (0.771) that are superior to the IT-4Cl-based device (PCE = 12.6%, FF = 0.758). The ThPy4-based device realizes the lowest energy loss and the smallest optical band gap, and the ternary PSC device based on PM6:BTP-eC9:ThPy4 exhibits a PCE of 18.43% and a FF of 0.802. Overall, this work sheds light on the great potential of thieno[3,2-b]pyrrole-based SMAs in realizing low energy loss and high PCE.

Keywords: energy loss; intramolecular non-covalent interactions; polymer solar cells; small-molecule acceptors; thieno[3,2-b]pyrrole.