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Using Cyclopenta[2,1‐ b :3,4‐ c′ ]dithiophene‐4‐one as a Building Block for Low‐Bandgap Conjugated Copolymers Applied in Solar Cells
Author(s) -
Zhang Wei,
Cao Jiamin,
Liu Ying,
Xiao Zuo,
Zhu Weiguo,
Zuo Qiqun,
Ding Liming
Publication year - 2012
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201200311
Subject(s) - conjugated system , copolymer , carbazole , materials science , band gap , fluorene , solubility , homo/lumo , absorption (acoustics) , polymer chemistry , crystallography , polymer , stereochemistry , photochemistry , chemistry , molecule , organic chemistry , optoelectronics , composite material
A novel electron‐accepting unit cyclopenta[2,1‐ b :3,4‐ c ′]dithiophene‐4‐one (CPDTO‐c′), which is an isomer of CPDTO‐b′ was developed. CPDTO‐c′ can be incorporated into the D–A backbone through 5, 7 positions. The 2 position of CPDTO‐c′ can be easily functionalized with an electron‐withdrawing chain. By copolymerizing CPDTO‐c′ with four different donor units: benzo[1,2‐ b :4,5‐ b′ ]dithiophene (BDT), dithieno[3,2‐ b :2′,3′‐ d ]silole (DTS), carbazole, and fluorene, four new conjugated copolymers P1 – P4 were obtained. All these polymers have good solubility and low‐lying HOMO energy levels (−5.41 ∼ −5.92 eV). Among them, P1 and P2 exhibit broad absorption and narrow optical bandgaps of 1.91 and 1.72 eV, respectively. Solar cells based on P1 /PC 71 BM afforded a PCE up to 2.72% and a high V oc up to ∼0.9 V.