IRUNC Advantages and Real Geometrical Dimensions of Microband Electrodes

Abstract

Microband electrodes have two important advantages relative to microdisks: (a) larger and thus more easily measured currents and (b) smaller ohmic drop (iRUNC). Measurements of electrode kinetics and of transport under linear diffusion conditions at microband electrodes require knowledge of their actual areas. This paper describes the use of microbands, fabricated by sandwiching a thin metal film between insulators (sandwich electrode) and by lithographic deposition of a thin metal strip on an insulating substrate (line electrode), under radial and linear diffusion conditions, achieved using respectively fluid and highly viscous solutions. When compared under linear diffusion conditions to microdisk and line electrodes, most sandwich microband electrodes have actual areas that are larger than their planned, geometrical areas. The difference is not revealed under radial diffusion conditions. This paper also describes linear diffusion experiments which test the theory that predicts smaller iRUNC effects at microbands relative to those at microdisks.