Synthesis and photovoltaic properties of amorphous polymers based on dithienylbenzothiadiazole-triphenylamine with hexyl side chains on different positions of thienyl groups

Authors

  • Takeshi Yasuda,

    Corresponding author
    • Organic Thin-Film Solar Cells Group, Photovoltaic Materials Unit, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan
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  • Yuki Shinohara,

    1. Material Engineering Advanced Course, Advanced Engineering School, Kurume National College of Technology, Kurume, Fukuoka, Japan
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  • Takaaki Matsuda,

    1. Department of Biochemistry and Applied Chemistry, Kurume National College of Technology, Kurume, Fukuoka, Japan
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  • Liyuan Han,

    1. Organic Thin-Film Solar Cells Group, Photovoltaic Materials Unit, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan
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  • Tsutomu Ishi-i

    Corresponding author
    1. Department of Biochemistry and Applied Chemistry, Kurume National College of Technology, Kurume, Fukuoka, Japan
    • Organic Thin-Film Solar Cells Group, Photovoltaic Materials Unit, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan
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Correspondence to: T. Yasuda (E-mail: YASUDA.Takeshi@nims.go.jp) or T. Ishi-I (E-mail: ishi-i@kurume-nct.ac.jp)

ABSTRACT

We synthesized and characterized three new amorphous dithienylbenzothiadiazole (TBT)-triphenylamine (TPA) polymers for application in bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells. Poly(3HTBT-TPA) has hexyl side chains on the thienyl groups (pointing toward the benzothiadiazole (BTD) unit), and poly(4HTBT-TPA) has hexyl side chains on the thienyl groups (pointing outward from the BTD unit). The incident photon to current conversion efficiencies (IPCEs) in the region from 550 to 650 nm for the OPV cells prepared using poly(4HTBT-TPA) were higher than those for the OPV cells prepared using poly(3HTBT-TPA) because the absorption spectrum for the poly(4HTBT-TPA) has a slightly red-shifted absorption edge. We also demonstrated that the poly(4HTBT-TPA)-based OPV performance is independent of the fabrication process, so using an amorphous film to fabricate BHJ OPV cells offers great advantages over using a polycrystalline film in terms of the high reproducibility of the OPV performance. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2536–2544

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