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Synthesis of Poly(benzothiadiazole-co-dithienobenzodithiophenes) and Effect of Thiophene Insertion for High-Performance Polymer Solar Cells

Authors

  • Hui-Jun Yun,

    1. School of Materials Science and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-772-1659
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  • Yun-Ji Lee,

    1. School of Materials Science and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-772-1659
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  • Seung-Jin Yoo,

    1. Department of Chemistry Gyeongsang National University and Research Institute of Nature Science (RINS), Gyeongsang National University, Jinju 660-701 (Korea)
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  • Prof. Dae Sung Chung,

    Corresponding author
    1. School of Chemical Engineering and Material Science, Chung-Ang University, Seoul 156-756 (Korea)
    • School of Chemical Engineering and Material Science, Chung-Ang University, Seoul 156-756 (Korea)
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  • Prof. Yun-Hi Kim,

    Corresponding author
    1. Department of Chemistry Gyeongsang National University and Research Institute of Nature Science (RINS), Gyeongsang National University, Jinju 660-701 (Korea)
    • Department of Chemistry Gyeongsang National University and Research Institute of Nature Science (RINS), Gyeongsang National University, Jinju 660-701 (Korea)
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  • Prof. Soon-Ki Kwon

    Corresponding author
    1. School of Materials Science and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-772-1659
    • School of Materials Science and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea), Fax: (+82) 55-772-1659
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Abstract

We describe herein the synthesis of novel donor–acceptor conjugated polymers with dithienobenzodithiophenes (DTBDT) as the electron donor and 2,1,3-benzothiadiazole as the electron acceptor for high-performance organic photovoltaics (OPVs). We studied the effects of strategically inserting thiophene into the DTBDT as a substituent on the skeletal structure on the opto-electronic performances of fabricated devices. From UV/Vis absorption, electrochemical, and field-effect transistor analyses, we found that the thiophene-containing DTBDT derivative can substantially increase the orbital overlap area between adjacent conjugated chains and thus dramatically enhance charge-carrier mobility up to 0.55 cm2 V−1 s−1. The outstanding charge-transport characteristics of this polymer allowed the realization of high-performance organic solar cells with a power conversion efficiency (PCE) of 5.1 %. Detailed studies on the morphological factors that enable the maximum PCE of the polymer solar cells are discussed along with a hole/electron mobility analysis based on the space-charge-limited current model.

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