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2D Side‐Chain Engineered Asymmetric Acceptors Enabling Over 14% Efficiency and 75% Fill Factor Stable Organic Solar Cells
Author(s) -
Cao Jinru,
Wang Hongtao,
Qu Shenya,
Yu Jiangsheng,
Yang Linqiang,
Zhang Zhuohan,
Du Fuqiang,
Tang Weihua
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202006141
Subject(s) - materials science , side chain , organic solar cell , energy conversion efficiency , conjugated system , thermal stability , molecular engineering , chemical engineering , electron mobility , phase (matter) , optoelectronics , polymer , nanotechnology , organic chemistry , composite material , chemistry , engineering
The charge transport and morphology of active layers are key considerations for device performance and stability in organic solar cells (OSCs). Such properties can be fine‐tuned via elaborate molecular design of fused‐ring electron acceptors (FREAs), especially conjugation extension and side chain engineering. In this work, N ‐functionalized conjugation is explored in the design of high‐efficient asymmetric FREAs. The twisting of N‐conjugated side chains from backbone endows three FREAs with similar energy levels and light absorptions (≈850 nm edge). Their blends with PBDB‐T exhibit high charge carrier mobility and ordered phase separation. Excitingly, IPT2F‐TT based OSCs yield a champion power conversion efficiency (PCE) of 14.02% with a fill factor (FF) of 75.06%, outperforming PBDB‐T devices with IPT2F‐Th (12.52%, 71.20%), IPT2F‐Ph (13.13%, 72.11%), and octylated IPT‐2F (13.70%, 71.50%). The PCE over 14% and FF over 75% are among the highest values for 2D FREAs OSCs reported to date. More importantly, outstanding thermal stability and light soaking stability are observed with PCE over 12% maintained after thermal or light aging for 100 h. This work demonstrates N ‐conjugated FREAs design as an effective strategy to simultaneously improve the photovoltaic performance and device stability for the OSCs.