The superiority of isomeric, fluorination and curtailed π-conjunction on A-D-A type acceptors for organic photovoltaics

Jin-Hong Han; Hai-Ping Zhou; Li-Li Wang; Zhi-Wen Zhao; Xing-Man Liu; Qing-Qing Pan; Zhong-Min Su

doi:10.1016/j.saa.2024.125043

The superiority of isomeric, fluorination and curtailed π-conjunction on A-D-A type acceptors for organic photovoltaics

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Aug 30:325:125043. doi: 10.1016/j.saa.2024.125043. Online ahead of print.

Authors

Jin-Hong Han¹, Hai-Ping Zhou¹, Li-Li Wang¹, Zhi-Wen Zhao², Xing-Man Liu³, Qing-Qing Pan⁴, Zhong-Min Su⁵

Affiliations

¹ School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Jilin Provincial International Joint Research Center of Photo-functional Materials and Chemistry, Changchun 130022, China.
² College of Chemical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China; School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China. Electronic address: zhaozw@hbuas.edu.cn.
³ School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China.
⁴ School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Jilin Provincial International Joint Research Center of Photo-functional Materials and Chemistry, Changchun 130022, China. Electronic address: panqq349@nenu.edu.cn.
⁵ School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Jilin Provincial International Joint Research Center of Photo-functional Materials and Chemistry, Changchun 130022, China; State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China. Electronic address: zmsu@nenu.edu.cn.

PMID: 39236567
DOI: 10.1016/j.saa.2024.125043

Abstract

The performance of organic solar cell (OSC) devices has been significantly enhanced by the dramatic evolution of A-D-A type non-fullerene acceptors (NFAs). Nevertheless, the structure-property-performance relationship of NFAs in the OSC device is unclear. Here, the intrinsic design factors of isomeric, fluorination and π-conjunction curtailing on the photophysical properties of benzodi (thienopyran) (BDTP) (named NBDTP-M, NBDTTP-M, NBDTP-F_in, and NBDTP-F_out)-based NFAs are discussed. The results show that fluorination on the terminal group of NBDTP-F_out could effectively decrease the highest occupied orbital (HOMO) energy level and the lowest unoccupied orbital (LUMO) energy level. And the long π-conjugated donor unit for NBDTTP-M could increase the HOMO energy level and bring a small HOMO-LUMO energy bandgap. Meanwhile, the substitution of external oxygen atoms and the fluorine atoms in the terminal group could introduce positive changes to the electrostatic potential of the NBDTP-F_out, favouring the charge separation at the donor/acceptor interface. Moreover, the structural design of external oxygen atom substitution, fluorination on the terminal group and curtailed π-conjugated donor unit could decrease the electron vibration-coupling of exciton diffusion, exciton dissociation and electronic transfer processes. The suppression of the exciton decay and charge recombination in those high-performance NFAs indicate that the investigated molecular designs could be effective for further improvement of OSCs.

Keywords: Non-fullerene acceptors; Organic solar cells; Photophysical properties; Quantum chemistry; Structure design.