An acceptor with an asymmetric and extended conjugated backbone for high-efficiency organic solar cells with low nonradiative energy loss

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-08, Vol.1 (31), p.16714-16721
• Main Authors: Wang, Jing, Chen, Hongbin, Xu, Xiaoyun, Ma, Zaifei, Zhang, Zhe, Li, Chenxi, Yang, Yang, Wang, Jian, Zhao, Yue, Zhang, Mingtao, Wan, Xiangjian, Lu, Yan, Chen, Yongsheng
• Format: Article
• Language: English
• Subjects: Asymmetry; Conjugation; Control equipment; Energy; Energy conversion efficiency; Energy levels; Energy loss; Molecular orbitals; Photoluminescence; Photons; Photovoltaic cells; Recombination; Solar cells; Solar energy
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta03956g

One of the significant factors that limit efficiencies of organic solar cells (OSCs) is their large energy loss ( E loss ), especially the high nonradiative recombination energy loss (Δ E nr ). Herein, an acceptor named NQF with an asymmetric and extended conjugation central core has been designed and synthesized. Compared with Y6, NQF exhibits upshifted HOMO and LUMO energy levels and a higher photoluminescence quantum yield (PLQY). The OSC based on PM6:NQF demonstrates a Δ E nr as low as 0.177 eV and thus a high power conversion efficiency (PCE) of 17.57%. In contrast, the control device PM6:Y6 gives a PCE of 16.45% with a Δ E nr value of 0.231 eV. This work achieves molecular design with low Δ E nr and demonstrates that the E loss of OSCs can be effectively reduced through rational and delicate molecular design. An asymmetric acceptor NQF is designed to minimize the nonradiative loss. Using this acceptor, a binary OSC is fabricated and offers an efficiency of 17.57% with a low nonradiative energy loss (Δ E nr ) of 0.177 eV.