Microelectrode arrays with active-area geometries defined by spatial light modulation

Abstract

Microelectrode arrays form the basis of electrochemical sensing devices because of their unique properties, such as enhanced mass transport and steady-state diffusion currents. However, they demand a predefined and rigid geometry, and require a connecting pad for each element of the array. Here it is reported the formation of microelectrode arrays whose geometry is defined by the shape of a light pattern projected on an unstructured silicon electrode. Spatiotemporally resolved fluxes of charge carriers are used to confine a model electrochemical reaction only to the illuminated areas. Using spatial light modulators, microelectrode geometry is adjusted instantaneously, at will, on a homogeneous semiconductor electrode carrying a single electrical connection. By developing a theoretical model to analyse the current−potential data, it is revealed within which limits spatial light modulation can be used to enhance, on silicon, the mass transport of a diffuse redox system.