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High‐Efficiency As‐Cast Organic Solar Cells Based on Acceptors with Steric Hindrance Induced Planar Terminal Group
Author(s) -
Liu Yahui,
Li Miao,
Yang Jinjin,
Xue Wenyue,
Feng Shiyu,
Song Jinsheng,
Tang Zheng,
Ma Wei,
Bo Zhishan
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201901280
Subject(s) - steric effects , homo/lumo , materials science , alkoxy group , organic solar cell , moiety , crystallinity , energy conversion efficiency , side chain , alkyl , scattering , substituent , crystallography , acceptor , stereochemistry , molecule , chemistry , organic chemistry , optics , physics , optoelectronics , condensed matter physics , composite material , polymer
A series of alkyl, alkoxyl, and alkylthio substituted A–π–D–π–A type nonfullerene acceptors (NFAs) IDTCN‐C , IDTCN‐O, and IDTCN‐S are designed and synthesized. The introduction of a lateral side chain at the outer position of the π bridge unit can endow the terminal moiety with a confined planar conformation due to the steric hindrance. Thus, compared with nonsubstituted NFA ( IDTT2F ), these acceptors tend to form favorable face‐on orientation and exhibit strong crystallinity as verified with grazing‐incidence wide‐angle X‐ray scattering measurement. Moreover, the variation of side chain can significantly change the lowest unoccupied molecular orbital (LUMO) energy level of acceptors. As state‐of‐the‐art NFAs, a power conversion efficiency of 13.28% ( V oc = 0.91 V, J sc = 19.96 mA cm −2 , and FF = 73.2%) is obtained for the as‐cast devices based on IDTCN‐O , which is among the highest value reported in literature. The excellent photovoltaic performance for IDTCN‐O can be attributed to its slightly up‐shifted LUMO level and more balanced charge transport. This research demonstrates side chain engineering is an effective way to achieve high efficiency organic solar cells.