Raman characterization and electrical properties of poly(3-hexylthiophene) doped electrochemically in an ionic liquid-gated transistor geometry

Jun Yamamoto, Yukio Furukawa

    Research output: Contribution to journalArticle

    12 Citations (Scopus)


    Using Raman spectroscopy, we observed carriers, polarons and bipolarons formed in an ionic-liquid-gated P3HT electrochemical transistor with an ionic liquid [BMIM][TFSI] as a gate dielectric. The relationships between the source-drain current (ID), the gate voltage (VG) at a constant source-drain voltage (VD), and injected charges at each VG were investigated. An increase in ID is attributed to the formation of positive polarons, whereas a decrease in ID corresponded to positive bipolarons. Thus, positive polarons are efficient carriers in P3HT electrochemical transistors. Charge densities, doping levels, electrical conductivities, and mobilities of polarons in P3HT were calculated from the electrochemical measurements. Only positive polarons exist below the dopant level x = 27 mol%, whereas at higher doping levels, polarons and bipolarons coexist. The mobility of polarons was dependent on the doping level. The highest mobility was 0.31 cm2 V-1 s-1 at x = 15 mol%.

    Original languageEnglish
    Pages (from-to)82-87
    Number of pages6
    JournalOrganic Electronics: physics, materials, applications
    Publication statusPublished - 2016 Jan 1



    • Bipolaron
    • Ionic liquid
    • Organic transistor
    • Polaron
    • poly(3-hexylthiophene)
    • Raman

    ASJC Scopus subject areas

    • Biomaterials
    • Electronic, Optical and Magnetic Materials
    • Materials Chemistry
    • Electrical and Electronic Engineering
    • Chemistry(all)
    • Condensed Matter Physics

    Cite this