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Stirring Up Acceptor Phase and Controlling Morphology via Choosing Appropriate Rigid Aryl Rings as Lever Arms in Symmetry‐Breaking Benzodithiophene for High‐Performance Fullerene and Fullerene‐Free Polymer Solar Cells
Author(s) -
Liu Deyu,
Wang Junyi,
Gu Chunyang,
Li Yonghai,
Bao Xichang,
Yang Renqiang
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201705870
Subject(s) - materials science , fullerene , acceptor , phase (matter) , organic solar cell , polymer , aryl , chemical physics , lever , nanotechnology , condensed matter physics , composite material , organic chemistry , physics , chemistry , alkyl , quantum mechanics
Two series of new polymers with medium and wide bandgaps to match fullerene (PC 71 BM) and fullerene‐free 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐ d :2′,3′‐ d ′]‐ s ‐indaceno[1,2‐ b :5,6‐ b ′]dithiophene (ITIC) acceptors are designed and synthesized, respectively. For constructing the key donor building blocks, the effective symmetry‐breaking strategy is employed. Two common aromatic rings (thiophene and benzene) are chosen as one side substituted groups in the asymmetric benzodithiophene (BDT) monomers. In addition, another rigid benzene ring is inserted between aryl and thioether in the side chains, which results in larger twisting and destroying the aggregation and forming longer lever arms. As a result, highly ordered polymers (PBDTsTh‐FBT and PBDTsPh‐FBT) with strong aggregation properties can blend well with roughly spherical PC 71 BM, while amorphous polymers (PBDTsThPh‐BDD and PBDTsPhPh‐BDD) with long and rigid aryl rings show good miscibility with elongated ITIC, and finally, both devices exhibit excellent power conversion efficiencies over 10%. Thus, it clearly shows that the asymmetric BDT unit is an excellent donor building block to construct highly efficient photovoltaic polymers. Meanwhile, this work demonstrates that it is not necessary that high‐performance fullerene‐free polymer solar cells (PSCs) require highly ordered microstructures in the blending films, different from the fullerene‐based PSCs.