Impedance study of the charge transport at poly- o-phenylenediamine film electrodes

• Published in: Electrochimica acta Vol. 41; no. 18; pp. 2865 - 2870
• Main Authors: Komura, Teruhisa, Yamaguti, Takahiro, Takahasi, Kousin
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1996; Elsevier
• Subjects: charge transport; Chemistry; electrochemical impedance; Electrochemistry; Exact sciences and technology; film electrode; General and physical chemistry; poly- o-phenylenediamine; Study of interfaces; Transport phenomena; poly- o-phenylenediamine; film electrode; electrochemical impedance; charge transport; Aniline derivative polymer; Experimental study; Redox polymer; Carbon; Acidic solution; Electrodes; Transport process; Perchloric acid; Capacitance; Diffusion coefficient; Glassy state; Electrical impedance; Modified material
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/0013-4686(96)00114-4

The measured low-frequency capacitance of the polymer film was proportional to the film thickness and showed a maximum at the formal potential of the polymer. We analyzed the relation between the capacitance and potential by taking into account the contribution of an interaction between electroactive sites. The Warburg coefficient and the width of a linear 45 ° region in an impedance diagram showed each their minima near the formal potential. These impedance data were interpreted in terms of the diffusion-migration transport of both electron and anion through the film. The results of the impedance analysis suggested that electron transport was ensured by interchain electron hopping. From the combinations of the measured kinetic parameters, we inferred that one of the two charge carriers moved much faster than the other. The obtained diffusion coefficient showed a maximum in the vicinity of a voltammetric current peak; this corresponded with the potential dependence of a coupled diffusion coefficient expected in the extreme case of electron-transport control.