Templated electrochemical synthesis of titania nanopillars on conductive substrates

We report a fabrication scheme for arrays of nanoscopic titania (TiO 2) pillars on a variety of conductive substrates including a transparent conductive oxide. Nanoporous polymeric templates of approximately 20 nm in diameter and up to 500 nm in height (aspect ratio 1:25) are prepared by oxygen plasma etching using a self-assembled block copolymer thin film as an etch mask. Titanyl hydroxide gel is electrochemically deposited into the nanopores of the template and crystallizes into anatase phase by thermal treatment. We investigated the effect of electrochemical deposition conditions, template and substrate materials, and wet etching conditions on the final morphology of TiO2 nanopillars. As demonstrated in this paper, this approach provides single or multilayered anatase titania nanopillars with approximately 20 nm in diameter, 100-400 nm in height, which find a variety of potential applications including photocatalysis and solar cells. © 2010 The Electrochemical Society.