Département de chimie moléculaire

The paper reports on the study of the electrochem. behavior of a thin Au film electrode coated with SiO2 (SiOx) layers of increasing thickness. Stable thin films of amorphous SiO2 (SiOx) were deposited on glass slides coated with a 5. nm adhesion layer of Ti and 50 nm of Au, using plasma-enhanced CVD (PECVD) technique. Scanning electrochem. microscopy (SECM) and electrochem. impedance spectroscopy (EIS) were used to study the electrochem. behavior of the interfaces. In the case of SECM, the influence of the SiOx thicknesses on the electron transfer kinetics of 3 redox mediators was studied. Normalized current-distance curves (approach curves) were fitted to the theor. model to find the effective heterogeneous 1st order rate const. (k eff) at the sample. EIS was in addn. used to confirm the diffusion barrier character of the SiOx interlayer. [on SciFinder(R)]