Get access
Advanced Materials

Drastic Change of Molecular Orientation in a Thiazolothiazole Copolymer by Molecular-Weight Control and Blending with PC61BM Leads to High Efficiencies in Solar Cells

Authors

  • Itaru Osaka,

    Corresponding author
    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
    2. Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Chiyoda-ku 102-0075, Japan
    • Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
    Search for more papers by this author
  • Masahiko Saito,

    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
    Search for more papers by this author
  • Hiroki Mori,

    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
    Search for more papers by this author
  • Tomoyuki Koganezawa,

    1. Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
    Search for more papers by this author
  • Kazuo Takimiya

    Corresponding author
    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
    2. Institute for Advanced Materials Research, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
    • Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
    Search for more papers by this author

Abstract

A thiazolothiazole–thiophene copolymer is examined as the active material in bulk heterojunction (BHJ) solar cells. By optimizing the molecular weight, the polymer-based cells exhibit power conversion efficiencies as high as 5.7%. The increase in molecular weight improves the orientational order, and blending with phenyl-C61-butyric acid methyl ester (PC61BM) changes the orientational motif from edge-on to face-on, which accounts for the trend in photovoltaic performances. These results might give new insight into the structure–property relationships in BHJ solar cells.

original image
Get access to the full text of this article

Ancillary