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ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 33, Number 6
BKCSDE 33(6)
June 20, 2012 |
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Title |
Synthesis and Photovoltaic Properties of Polymers Based on Cyclopentadithiophene and Benzimidazole Units |
Author |
Suhee Song, Seijung Park, Sooncheol Kwon, Joo Young Shim, Youngeup Jin, Sung Heum Park, Il Kim, Kwanghee Lee, Hongsuk Suh* |
Keywords |
Polymer, Photovoltaic cells, Synthesis, Dimethyl-2H-benzimidazole |
Abstract |
The new semiconducting copolymers with 4,4-dialkyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene and 2,2-dimethyl- 2H-benzimidazole units were synthesized. The fused aromatic rings, such as cyclopentadithiophene (CPDT) unit, can make the polymer backbone more rigid and coplanar, which induces long conjugation length, narrow band gap, and strong intermolecular π-π interaction. The stacking ability was controlled through attaching of linear or branched alkyl side chains. The spectra of PEHCPDTMBI and PHCPDTMBI in the solid films show absorption bands with maximum peaks at 401, 759 and 407, 768 nm, and the absorption onsets at 925 and 954 nm, corresponding to band gaps of 1.34 and 1.30 eV, respectively. The devices comprising PHCPDTMBI with TiOX showed a VOC of 0.39 V, a JSC of 1.14 mA/cm2, and a FF of 0.34, giving a power conversion efficiency of 0.15%. The PHCPDTMBI with linear alkyl chain on CPDT shows good solubility in organic solvent with higher PCE value than that of PEHCPDTMBI. |
Page |
1861 - 1866 |
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