Voltammetric and Electrochemical Impedance Spectroscopy Study of Prussian Blue/Polyamidoamine Dendrimer Films on Optically Transparent Electrodes

Electrochromic Prussian Blue (PB) films were prepared on clean and dendrimer modified optically transparent electrodes (OTE). As expected, surface attached polyamidoamine (PAMAM) dendrimers, modified not only the chemical structure but also the electric properties of the interphase and therefore, exerted a clear influence on the electrochromic behavior of the PB films. The electrochromic efficiency of the modified substrate for instance, was clearly dependent on the size (Generation, G) of the surface confined dendrimer molecule, and the effects on this and other properties of the electrode could be associated to ion transport of charge compensating species (K+, Cl−) as well as effects on electrochemical charge transfer (resistance to the electronic transfer) of the electrochromic films. Using Electrochemical Impedance Spectroscopy (EIS) experiments of the dendrimer modified interphases under study, fitted values of the electric components of an equivalent circuit were obtained and used to gain understanding of the dendrimer induced effects of the electrochromic response of PB films. This study is expected to contribute to the understanding of this type of interphases so that the design and construction of electrochromic films in which ionic as well as electronic transport, can be properly tailored and employed.