Monte-Carlo simulation of linear sweep voltammograms during redox switching of conducting polymers

Abstract

We propose a derived approach from the model of the moving front, that includes ionic transport in the redox process of conducting polymers. The moving front is the border between the insulating and conducting zones, where oxidation takes place. In our approach, the conversion of a polymer site from reduced to oxidised state requires simultaneously an electron transfer with the electrode and the presence of a dopant ion. When both conditions are fulfilled, oxidation occurs: the dopant ion remains trapped and the front is shifted toward the neighbour site. Ionic motion inside the film is assumed to be one-dimensional diffusion, and is simulated by Monte-Carlo. Simulated voltammograms are thus obtained and analysed as a function of scan rate. A diffusion limited regime was actually observed at low scan rate, but the high scan rate behaviour is somewhat different from experimental profiles. This tends to show the necessity to include a migration component in the dopant transport, in order to improve the description of the redox process of conducting polymers.