Effect of nitro-substituted ending groups on the photovoltaic properties of nonfullerene acceptors
writer：Jing Wang, Yunqian Ding, Chenxi Li, Nan Zheng, Zengqi Xie, Zaifei Ma, Yan Lu,* et al.
keywords：nonfullerene acceptor; organic solar cell, nitration
source：期刊
specific source：ACS Appl. Mater. Interfaces, 2020, 12, 41861-41868
Issue time：2020年
Chemical modification of end groups has proved to be an effective way to design
new acceptor?donor?acceptor (A?D?A)-structured nonfullerene acceptors (NFAs) for highperformance organic solar cells (OSCs). Herein, we designed and synthesized two nitrosubstituted end groups, N1 and N2. Using the two end groups as A units, two A?D?A acceptors, F-N1 and F-N2, were obtained. It also has been found that the nitro substitution position on end groups affects not only the absorptions and energy levels of the resultant acceptor materials but also their molecular packing behavior and active layer morphologies. In addition, the devices based on the two acceptors showed different energy losses. Power-conversion efficiencies (PCEs) of 10.66 and 11.86% were achieved for F-N1- and F-N2-based devices, respectively. This work reveals that the nitration of end groups is one of the potential strategies for designing high-performance photovoltaic active layer materials.