Structure, Electronic Properties and Electrochemical Behavior of a Boron-Doped Diamond/Quartz Optically Transparent Electrode

Abstract

This presentation will review the morphology, microstructure, chemistry, electronic properties and electrochemical behavior of a boron-doped nanocrystalline diamond (BDD) thin film grown on quartz. Diamond optically transparent electrodes (OTEs) are useful for transmission spectroelectrochemical measurements offering excellent stability during anodic and cathodic polarization and exposure to a variety of chemical environments.1,2 An example will be shown of how the OTE in a spectroelectrochemical measurement can be used to study the redox mechanism of the model analyte, chlorpromazine.1 We will also report on the characterization of the BDD OTE by AFM, optical spectroscopy, Raman spectroscopic mapping, AC Hall Effect measurements, XPS and electrochemical methods. Cyclic voltammetry was used to investigate the background current response as a function of potential, scan rate and electrolyte composition. Cyclic voltammetry and digital simulation were used to determine the heterogeneous electron-transfer rate constants (ko) for IrCl6 2-/3-, Fe(CN)6 3-/4-, ferrocene carboxylic acid, Ru(NH3)6 3+/2+ and methyl viologen. The diamond OTE supports relatively rapid electron transfer for a wide range of redox systems with formal potentials from ca. 0.9 to -1.0 V vs. Ag/AgCl. Capacitance-potential measurements were made in aqueous electrolyte solutions and ionic liquids to better understand the organization of electrified interfaces formed at this electrode. The work constitutes the first comprehensive study of the relationship between the physical and chemical structure and electronic properties of a diamond OTE, and the electrode’s electrochemical activity. 1. Stotter, J; Zak J; Behler Z; Show Y; Swain GM. Optical and Electrochemical Properties of Optically Transparent, Boron-Doped Diamond Thin Films on Quartz. Anal. Chem. 2002, 74, 5924-5930. 2. Stotter J; Show Y; Wang S; Swain GM. Comparison of the Electrical, Optical and Electrochemical Properties of Diamond and Indium Tin Oxide Thin-Film Electrodes. Chem. Mater. 2005, 17, 4880-4888.