Optimizing Molecular Packing via Steric Hindrance for Reducing Non-Radiative Recombination in Organic Solar Cells

Junzhen Ren; Shaoqing Zhang; Zhihao Chen; Tao Zhang; Jiawei Qiao; Jingwen Wang; Lijiao Ma; Yang Xiao; Zi Li; Jianqiu Wang; Xiaotao Hao; Jianhui Hou

doi:10.1002/anie.202406153

Optimizing Molecular Packing via Steric Hindrance for Reducing Non-Radiative Recombination in Organic Solar Cells

Angew Chem Int Ed Engl. 2024 May 10:e202406153. doi: 10.1002/anie.202406153. Online ahead of print.

Authors

Junzhen Ren¹, Shaoqing Zhang², Zhihao Chen¹, Tao Zhang¹, Jiawei Qiao³, Jingwen Wang¹, Lijiao Ma¹, Yang Xiao¹, Zi Li¹, Jianqiu Wang¹, Xiaotao Hao³, Jianhui Hou⁴

Affiliations

¹ Institute of Chemistry Chinese Academy of Sciences, State Key Laboratory of Polymer Physics and Chemistry, CHINA.
² University of Science and Technology Beijing, School of Chemistry and Biology Engineering, 2, 100083, , CHINA.
³ Shandong University, School of physics, CHINA.
⁴ Institute of Chemistry Chinese Academy of Sciences, Institute of chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, 100190, Beijing, CHINA.

PMID: 38730419
DOI: 10.1002/anie.202406153

Abstract

Innovative molecule design strategy holds promise for the development of next-generation acceptor materials for efficient organic solar cells with low non-radiative energy loss (ΔEnr). In this study, we designed and prepared three novel acceptors, namely BTP-Biso, BTP-Bme and BTP-B, with sterically structured triisopropylbenzene, trimethylbenzene and benzene as side chains inserted into the shoulder of the central core. The progressively enlarged steric hindrance from BTP-B to BTP-Bme and BTP-Biso induces suppressed intramolecular rotation and altered the molecule packing mode in their aggregation states, leading to significant changes in absorption spectra and energy levels. By regulating the intermolecular π-π interactions, BTP-Bme possesses relatively reduced non-radiative recombination rate and extended exciton diffusion lengths. The binary device based on PB2:BTP-Bme exhibits an impressive power conversion efficiency (PCE) of 18.5% with a low ΔEnr of 0.19 eV. Furthermore, the ternary device comprising PB2:PBDB-TF:BTP-Bme achieves an outstanding PCE of 19.3%. The molecule design strategy in this study proposed new perspectives for developing high-performance acceptors with low ΔEnr in OSCs.

Keywords: Organic Solar Cells, Steric Hindrance Groups, Molecule Packing, Low Non-radiative Recombination, High Performance.