A Morphological Model for the Solvent-Enhanced Conductivity of PEDOT:PSS Thin Films

Authors

  • Alexandre Mantovani Nardes,

    1. Molecular Materials and Nanosystems Department of Applied Physics Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven (The Netherlands)
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  • René A. J. Janssen,

    1. Molecular Materials and Nanosystems Department of Applied Physics Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven (The Netherlands)
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  • Martijn Kemerink

    Corresponding author
    1. Molecular Materials and Nanosystems Department of Applied Physics Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven (The Netherlands)
    • Molecular Materials and Nanosystems Department of Applied Physics Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven (The Netherlands)
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  • We thank Dr. Albert J. J. M. van Breemen of TNO Science and Industry and Dr. Margreet de Kok of Philips for providing materials and discussions. A. M. Nardes acknowledges the Alβan Program (the European Union Programme of High Level Scholarships for Latin America, ID#E03D19439BR) for the financial support.

Abstract

The well-known enhanced conductivity of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) thin films that is obtained by addition of high-boiling solvents like sorbitol to the aqueous dispersion used for film deposition is shown to be associated with a rearrangement of PEDOT-rich clusters into elongated domains, as evidenced from STM and AFM. Consistently, temperature dependent conductivity measurements for sorbitol-treated films reveal that charge transport occurs via quasi 1D variable range hopping (VRH), in contrast to 3D VRH for untreated PEDOT:PSS films. The typical hopping distance of 60–90 nm, extracted from the conductivity measurements is consistent with hopping between the 30–40 nm sized grains observed with scanning probe microscopy.

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