IR(UNC) ADVANTAGES AND REAL GEOMETRICAL DIMENSIONS OF MICROBAND ELECTRODES

Microband electrodes have two important advantages relative to microdi sks: (a) larger and thus more easily measured currents and (b) smaller ohmic drop (iR(UNC)). Measurements of electrode kinetics and of trans port under linear diffusion conditions at microband electrodes require knowledge of their actual areas. This paper describes the use of micr obands, fabricated by sandwiching a thin metal film between insulators (sandwich electrode) and by lithographic deposition of a thin metal s trip on an insulating substrate (line electrode), under radial and lin ear 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 hav e 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 theo ry that predicts smaller iR(UNC) effects at microbands relative to tho se at microdisks.