Revealing the Sole Impact of Acceptor's Molecular Conformation to Energy Loss and Device Performance of Organic Solar Cells through Positional Isomers

Guilong Cai; Zeng Chen; Mengyang Li; Yuhao Li; Peiyao Xue; Qingbin Cao; Weijie Chi; Heng Liu; Xinxin Xia; Qiaoshi An; Zheng Tang; Haiming Zhu; Xiaowei Zhan; Xinhui Lu

doi:10.1002/advs.202103428

Revealing the Sole Impact of Acceptor's Molecular Conformation to Energy Loss and Device Performance of Organic Solar Cells through Positional Isomers

Adv Sci (Weinh). 2022 May;9(15):e2103428. doi: 10.1002/advs.202103428. Epub 2022 Mar 24.

Authors

Guilong Cai¹, Zeng Chen², Mengyang Li³, Yuhao Li¹, Peiyao Xue⁴, Qingbin Cao⁵, Weijie Chi⁶, Heng Liu¹, Xinxin Xia¹, Qiaoshi An⁵, Zheng Tang³, Haiming Zhu², Xiaowei Zhan⁴, Xinhui Lu¹

Affiliations

¹ Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong, 999077, China.
² State Key Laboratory of Modern Optical Instrumentation, Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, 310030, China.
³ Center for Advanced Low-dimension Materials, State Key Laboratory for Modi cation of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, China.
⁴ School of Materials Science and Engineering, Peking University, Beijing, 100871, China.
⁵ School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
⁶ Fluorescence Research Group, Singapore University of Technology and Design, Singapore, 487372, Singapore.

Abstract

Two new fused-ring electron acceptor (FREA) isomers with nonlinear and linear molecular conformation, m-BAIDIC and p-BAIDIC, are designed and synthesized. Despite the similar light absorption range and energy levels, the two isomers exhibit distinct electron reorganization energies and molecular packing motifs, which are directly related to the molecular conformation. Compared with the nonlinear acceptor, the linear p-BAIDIC shows more ordered molecular packing and higher crystallinity. Furthermore, p-BAIDIC-based devices exhibit reduced nonradiative energy loss and improved charge transport mobilities. It is beneficial to enhance the open-circuit voltage (V_OC ) and short-current current density (J_SC ) of the devices. Therefore, the linear FREA, p-BAIDIC yields a relatively higher efficiency of 7.71% in the binary device with PM6, in comparison with the nonlinear m-BAIDIC. When p-BAIDIC is incorporated into the binary PM6/BO-4Cl system to form a ternary system, synergistic enhancements in V_OC , J_SC , fill factor (FF), and ultimately a high efficiency of 17.6% are achieved.

Keywords: bridge effect; fused-ring electron acceptors; nonfullerene acceptors; organic solar cells; positional isomer.

Abstract

Grants and funding