Electrochemical impedance spectroscopy of oxidized poly(3,4-ethylenedioxythiophene) film electrodes in aqueous solutions

Johan Bobacka, Andrzej Lewenstam, Ari Ivaska

Tutkimustuotos: LehtiartikkeliArtikkeliTieteellinenvertaisarvioitu

333 Sitaatiot (Scopus)

Abstrakti

The electrochemical properties of oxidized (p-doped) poly(3,4-ethylenedioxythiophene) (PEDOT) film electrodes in aqueous solutions were investigated by electrochemical impedance spectroscopy (EIS). PEDOT was electrochemically deposited on platinum from aqueous solutions containing 0.01 M 3,3-ethylenedioxythiophene (EDOT) and 0.1 M supporting electrolyte: KCl, NaCl or poly(sodium 4-styrenesulfonate) (NaPSS). Impedance spectra were obtained for Pt/PEDOT electrodes at de potentials where PEDOT is in the oxidized (p-doped) state. Electrodes with PEDOT films of different thickness, containing different doping ions, were investigated in contact with different aqueous supporting electrolyte solutions. The EIS data were fitted to an equivalent electrical circuit in order to characterize the electrochemical properties of the Pt/PEDOT film electrodes. Best fits to the experimental impedance data were obtained for an equivalent circuit where the total bulk (redox) capacitance of the polymer film is composed of the diffusional pseudocapacitance in series with a second bulk capacitance. The results imply that the PEDOT film contains an excess of supporting electrolyte, which facilitates ion diffusion and gives rise to a large diffusional pseudocapacitance. (C) 2000 Elsevier Science S.A. All rights reserved.
AlkuperäiskieliEi tiedossa
Sivut17–27
Sivumäärä11
JulkaisuJournal of Electroanalytical Chemistry
Vuosikerta489
Numero1-2
DOI - pysyväislinkit
TilaJulkaistu - 2000
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

Keywords

  • ac impedance
  • equivalent circuit
  • capacitance

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