Improved organic solar cell efficiency based on the regulation of an alkyl chain on chlorinated non-fullerene acceptors. (22nd June 2020)

• Record Type: Journal Article
• Authors: Yu, Han; Ma, Ruijie; Xiao, Yiqun; Zhang, Jianquan; Liu, Tao; Luo, Zhenghui; Chen, Yuzhong; Bai, Fujin; Lu, Xinhui; Yan, He; Lin, Haoran
• Is Part Of: Materials chemistry frontiers. Volume 4:Number 8(2020)
• Page Start: 2428
• Page End: 2434
• Publication Date: 2020-06-22
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/d0qm00151a
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : A new non-fullerene acceptor with third-positioned branched alkyl side chains exhibit efficiency of 16.53% in solar cell devices. Abstract : Non-fullerene acceptors (NFAs) have attracted significant research attention as they enable high-performance organic solar cells (OSCs). Recently, a new NFA named Y6 was reported to yield highly efficient OSCs with efficiency up to 15.7%. Then, the research interests regarding the structure–property relationship and further structural optimization of Y6 have risen sharply. In this study, we report a new NFA, N3-4Cl, using IC-2Cl as the end group and replacing the alkyl side chains on the N -position of the pyrrole unit with branched side chains on the third position. The combined substitution on Y6 yields electronic effects on energy levels and thus the open-circuit voltage ( V oc ) of the corresponding OSCs. The lowest unoccupied molecular orbital (LUMO) level of N3-4Cl is up-shifted compared to that of Y6-4Cl ; thus, a higher V oc of 0.85 V is obtained. In addition, PM6 : an N3-4Cl blend film can also maintain an optimal blend morphology with reasonably high and balanced charge mobility, which leads to a high fill factor (FF) of up to 74.9%. As a result, PM6 :N3-4Cl -based device reached a PCE of 16.5% in binary devices. The results suggest that tuning the side chains of NFAs is an effective method for optimizing energy levels and aggregation properties, thus enhancing the OSC performances.