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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Electrochemical impedance spectroscopy of dodecylsulphate doped polypyrrole films in the dark and under illumination

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Author(s):
Milena Martini [1] ; Tullio Matencio [2] ; Nicolás Alonso-Vante [3] ; Marco-Aurélio De Paoli [4]
Total Authors: 4
Affiliation:
[1] Universidade de São Paulo. Instituto de Física. Departamento de Física Aplicada - Brasil
[2] Universidade Federal de Minas Gerais. ICEx. Departamento de Química - Brasil
[3] Universite de Poitiers. UMR-CNRS 6503 - França
[4] Universidade Estadual de Campinas. Instituto de Química - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Journal of the Brazilian Chemical Society; v. 11, n. 1, p. 50-58, 2000-02-00.
Abstract

The morphology, thickness, oxidation and illumination effects in dodecylsulphate doped polypyrrole films can be qualitatively observed by EIS and consist in variations of interfacial and bulk resistances and capacitances of a proposed equivalent circuit. The circuit well with the measured spectra of films obtained with 190 mC cm-2 of synthesis charge density. For thinner films the calculated values observed by electrochemical impedance spectroscopy (EIS) deviate probably due to the absence of diffusion effects. The oxidation of the films diminishes the total impedance over the entire frequency range. The morphology effects are also observed in the entire spectra. The illumination effects are reversible and are observed as expected only in the reduced form of the polymer. The illumination reduces the internal resistance and the space-charge capacitance and increases the charge transfer resistance and the double layer capacitance. (AU)