Large Area Plasmonic Gold Nanopillar 3-D Electrodes

Abstract

Three dimensional (3-D) periodic nanopillar electrodes have a significantly increased electroactive surface area compared to a conventional flat surface. The fabrication of organized nanostructured surfaces generally require advanced nanofabrication methods. Those can be both time-consuming and expensive. Moreover, the use of nanostructured electrodes combined with optical methods in studies of electrochemical processes provides a distinct advantage for the investigation of mechanistic details, since it adds another dimension to the classical electrochemical approaches. In this work, we have implemented a method, based on interference lithography technique, for the fabrication of 3-D nanopillar electrodes. The electrical current measured from those high-density 3-D nanopillars was ⿼17% higher than from a smooth gold surface, which was confirmed by numerical simulations using COMSOL®. Finally, gold-coated nanopillar electrodes support the phenomenon of surface plasmon resonance (SPR). Therefore, the optical characteristic of the surface (SPR) was measured simultaneously to the classical electrochemical data. A simple reversible redox system (ferrocyanide/ferricyanide) was used in a proof-of-concept experiment to demonstrate this application of the nanostructured surface.