Rui Sun,Yao Wu,Xinrong Yang,Yuan Gao,Zeng Chen,Kai Li,Jiawei Qiao,Tao Wang,Jing Guo,Chao Liu,Xiaotao Hao,Haiming Zhu,Jie Min.Single-Junction Organic Solar Cells with 19.17% Efficiency Enabled by Introducing One Asymmetric Guest Acceptor.Advanced Materials(闵杰)

        Abstract：

        The ternary strategy has been widely identified as an effective approach to obtaining high-efficiency organic solar cells (OSCs). However, for most ternary OSCs, the non-radiative voltage loss lies between those of the two binary devices, which limits further efficiency improvements. Herein, we designed an asymmetric guest acceptor BTP-2F2Cl and incorporated it into the PM1:L8-BO host blend. Compared with the L8-BO neat film, the L8-BO:BTP-2F2Cl blend film shows higher photoluminescence quantum yield and larger exciton diffusion length. Introducing BTP-2F2Cl into the host blend extends its absorption spectra, improves the molecular packing of host materials, and suppresses the non-radiative charge recombination of the ternary OSCs. Consequently, the PCE is improved up to 19.17% (certified value 18.7%), which represents the highest efficiency value reported for single-junction OSCs so far. The results show that improving the exciton behaviors is a promising approach to reducing the non-radiative voltage loss and realizing high-performance OSCs.

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        https://onlinelibrary.wiley.com/doi/10.1002/adma.202110147