Template preparation of nanoelectrode ensembles. Achieving the ‘pure-radial’ electrochemical-response limiting case

Abstract

We have been investigating a new method for preparing ensembles of disc-shaped nanoscopic electrodes. This method entails deposition of the electrode material into the pores of a nanoporous membrane. Nanoscopic wires of the electrode material, with monodisperse diameters, are obtained in each pore. The ends of these nanowires (at one face of the membrane) define the ensemble of disc-shaped nanoelectrodes. We call this approach for preparing nanoelectrode ensembles (NEEs) the template method. In all our prior investigations the electrode elements in the NEE were so close together that the diffusion layers at the elements overlapped. This is called the ‘total-overlap’ electrochemical-response limiting case. Here, we demonstrate (for the first time) that it is possible to use the template method to prepare NEEs with elements so widely spaced that the diffusion layers are completely isolated. The key to achieving this ‘pure-radial’ limiting case is obtaining template membranes with very low porosities.