Optical and electrochemical evaluation of colloidal Au nanoparticle-ITO hybrid optically transparent electrodes and their application to attenuated total reflectance spectroelectrochemistry

Abstract

Colloidal Au nanoparticle monolayers covalently deposited on conductive layers of indium tin oxide (ITO) were fabricated and evaluated as optically transparent electrodes (OTEs) for spectroelectrochemical applications. Specifically, the electrodes were characterized using UV-Vis spectroscopy and cyclic voltammetry; comparisons are made with other types of hybrid ITO optically transparent electrodes. The optical modulation of surface-bound colloidal Au in response to potential cycling over a wide potential window (0.6 to −1.0 V) was acquired in an attenuated total reflectance (ATR) spectroelectrochemical cell. Finally, uptake of a model analyte, tris-(2,2′-bipyridyl)ruthenium(II) chloride, into a Nafion charge selective film spin coated onto the colloidal Au-ITO hybrid electrode was examined using ATR absorbance spectroelectrochemistry. Dependence of uptake on film thickness is addressed, and non-optimized detection limits of 10 nM are reported.