Asymmetric electron acceptor enables highly luminescent organic solar cells with certified efficiency over 18%

Enhancing the luminescence property without sacrificing the charge collection is one key to high-performance organic solar cells (OSCs), while limited by the severe non-radiative charge recombination. Here, we demonstrate efficient OSCs with high luminescence via the design and synthesis of an asymmetric non-fullerene acceptor, BO-5CI. Blending BO-5CI with the PM6 donor leads to a record-high electroluminescence external quantum efficiency of 0.1%, which results in a low non-radiative voltage loss of 0.178 eV and a power conversion efficiency (PCE) over 15%. Importantly, incorporating BO-5CI as the third component into a widely-studied donor:acceptor (D:A) blend, PM6:BO-4CI, allows device displaying a high certified PCE of 18.2%. Our joint experimental and theoretical studies unveil that more diverse D:A interfacial conformations formed by asymmetric acceptor induce optimized blend interfacial energetics, which contributes to the improved device performance via balancing charge generation and recombination.

Chengliang He, Zeng Chen, Tonghui Wang, Ziqiu Shen, Yaokai Li, Jiadong Zhou, Jianwei Yu, Huiyu Fang, Yuhao Li, Shuixing Li, Xinhui Lu, Wei Ma, Feng Gao, Zengqi Xie, Veaceslav Coropceanu, Haiming Zhu, Jean-Luc Bredas, Lijian Zuo, Hongzheng Chen