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

Autor(es)

Milena Martini ^[1] ; Tullio Matencio ^[2] ; Nicolás Alonso-Vante ^[3] ; Marco-Aurélio De Paoli ^[4]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 11, n. 1, p. 50-58, 2000-02-00.

Resumo

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)

• Processo FAPESP: 97/03968-1 - Propriedades fotoeletroquímicas do polipirrol-dodecilsulfato, PPy-DS: medidas de impedância eletroquímica, efeito da morfologia e polimerização induzida por irradiação de um semicondutor inorgânico
• Beneficiário: Milena Martini
• Modalidade de apoio: Bolsas no Brasil - Doutorado