Realizing compact three-dimensional charge transport networks of asymmetric electron acceptors for efficient organic solar cells  

作　　者：Jinlong Cai Yiwei Fu Chuanhang Guo Donghui Li Liang Wang Chen Chen Dan Liu Wei Li Tao Wang 

机构地区：[1]School of Materials Science and Engineering,Wuhan University of Technology,Wuhan,430070,China

出　　处：《Science China Chemistry》2023年第2期508-517,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(52073221,52273196)。

摘　　要：Asymmetry has been demonstrated an effective approach in recent years to tune the structural and energetic orders of nonfullerene electron acceptors(NFAs)to prepare efficient organic solar cells(OSCs).In this article,five asymmetric NFAs,namely C9BTP-BO-Th Cl-2F,C9BTP-BO-Cl-2F,C9BTP-BO-2Cl-2F,C7BTP-BO-2Cl-2F and C5BTP-BO-2Cl-2F possessing varied asymmetric end-groups and alkyl chains are synthesized to tune the charge transport networks formed within these NFAs.We found that the enhanced planarity in the asymmetric NFA can facilitate closerπ-πstacking distance in either the A-to-A or A-toD type NFA dimers,whilst the larger dipole moment can promote the formation of three-dimensional(3D)charge transport networks among NFAs.Taking those advantages,C7BTP-BO-2Cl-2F exhibit a compact 3D honeycomb network with a high packing coefficient of 72.1%and molecular packing density of 0.48 g/cm^(3),contributing to a superior power conversion efficiency of 18.0%when employing PM6 as the donor,with an open-circuit voltage of 0.85 V,short-circuit current of26.7 m A cm^(-2)and fill factor of 79.3%.Our work provides guidelines in engineering the end group and side chains of asymmetric NFAs to achieve compact charge transport networks for high efficiency OSCs.

关 键 词：organic solar cells asymmetric non-fullerene electron acceptor PLANARITY dipole moment charge transport networks 

分 类 号：TM914.4[电气工程—电力电子与电力传动]