IMPEDANCE ANALYSIS OF PRUSSIAN-BLUE FILMS DEPOSITED ON ITO ELECTRODES

A study of the electrochemical impedance spectroscopy (EIS) of Prussian Blue (PB) films deposited on Indium Tin Oxide (ITO) electrodes in a 1 M KCl solution has been carried out in this work. The charge transport process across the film is modeled with an equivalent circuit considering two phases and two kinds of charge transport in Prussian Blue films. The dependence of diffusion coefficients and other circuit parameters with film thickness and the redox-state of the film has been studied. Diffusion coefficients reach a maximum value near the equilibrium potential and the charge transport resistance at the ITO/PB interface has a minimum value at these potentials. The total capacitance has a linear dependency with film thickness and could be used to measure the amount of Prussian Blue deposited.