Nucleation and growth mechanism of manganese oxide electrodeposited on ITO substrate

Abstract

To understand the electrodeposition mechanism of manganese oxide from sulfate manganese solutions on Indium doped Tin Oxide, the cyclic voltammetry and the chronoamperometry have been used to study the kinetics, nucleation and the growth mechanism respectively. However, given the variation of scan rate, the voltammograms show that the electrodeposition reaction is a quasi-reversible reaction controlled by the diffusion of manganese ions. Based on the chronoamperograms obtained and the physical models proposed by Scharifker-hills, the nucleation and growth mechanism of manganese oxide on the indium tin oxide substrate follow the instantaneous three-dimensional process despite the value of applied potential or the manganese ions concentration. The characterization by scanning electronic microscope confirmed this result. Thus, the effect of this value on the electrical proprieties of thin films electrodeposited has been studied using the electrochemical impedance spectroscopy. It was found that the charge transfer resistance of the samples increases along with ions concentration or with the decrease of applied potential.