Photosensitive Semiconductor- Metal Nanocomposites: Preparation, Surface Characterization and Electrochemical Studies

摘要

Metal deposited semiconductor nanoparticles can alter the selectivity of chemical reactions, enhance their rates and decrease charge recombination under UV illumination. The present work outlines the preparation of titanium dioxide semiconductor films using the sol gel process and the preparation of metal nanoparticles, in an organic medium, using a phase transfer catalyst. The metal nanoparticles are deposited on thin, transparent TiO_2 films prepared on glass substrates. Controlled metal deposition is achieved by an electrophoretic approach. Microscopic studies of the surface topography using AFM and SEM shows that the nanoporous films to be composed of ～ 20-30 nm sized particles with islands of metal deposits. Photoelectrochemical measurements of the TiO_2/metal film composites show order of magnitude increase in photocurrent and photovoltage during UV illumination. Cyclic voltametry studies show weak peaks at +0.48V and 0.38V that suggest the occurrence of a redox couple whose nature has not been ascertained yet.