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The Twisted Benzo[ ghi ]‐Perylenetriimide Dimer as a 3D Electron Acceptor for Fullerene‐Free Organic Photovoltaics
Author(s) -
Chen HungCheng,
Jiang BingHuang,
Hsu ChaoPing,
Tsai YaoYu,
Jeng RuJong,
Chen ChihPing,
Wong KenTsung
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804088
Subject(s) - organic solar cell , acceptor , homo/lumo , alkyl , fullerene , materials science , energy conversion efficiency , dimer , photochemistry , electron acceptor , side chain , chemistry , crystallography , polymer , optoelectronics , molecule , organic chemistry , physics , condensed matter physics
A series of twisted N,N‐linked benzo[ ghi ]‐perylenetriimide dimers (t‐BPTI) with various lengths of the α‐branched alkyl side chain at the six‐membered imide ring position was designed, synthesized, and characterized. These compounds showed the low‐lying LUMO energy level of −3.78 eV, which was similar to that of PC 61 BM (−3.71 eV), but with intensive optical absorption in the range 350–500 nm. The twisted molecular geometry with two nearly perpendicular BPTI planes achieved a favorable nanoscale phase separation by relieving the self‐aggregation of rigid BPTI units in blend films. The acceptor t‐BPTI‐3 unit with the longest alkyl side chains has been demonstrated to be an efficient electron acceptor in solution‐processed bulk heterojunction organic photovoltaics (OPV), giving a power conversion efficiency of 3.68 % when using conjugated polymer PTB7‐Th as the donor and without additional treatments.