Fabrication of TiO₂ and metal nanoparticle-microelectrode arrays by photolithography and site-selective photocatalytic deposition

This paper demonstrates a novel and facile technique for the production of microelectrode arrays based on either TiO₂ or metal nanoparticles, which combines photolithography and photocatalytic deposition. A procedure that involves photolithographic selective decomposition of superhydrophobic n-octadecyltriethoxysilane (ODS) has been developed to create superhydrophobic/superhydrophilic TiO₂ patterns (i.e., microelectrode arrays based on TiO₂ nanoparticles). The generated TiO₂ patterns can function as molecular microtemplates, in which elevated metal nanoparticle-based microelectrode arrays are produced by photocatalytic deposition to form microelectrode arrays based on metal nanoparticles. Microscopy and atomic force microscopy have demonstrated that the metal nanoparticles grow siteselectively inside the TiO₂ microtemplates. This developed approach can be used to create microelectrode arrays composed by either TiO₂ nanoparticles or various metal nanoparticles, such as gold, silver, and platinum, with different patterns. The electrochemical behavior of the as-prepared microelectrode arrays has also been characterized by cyclic voltammetry.