Paper Title
UV Plasmonic Enhancement for TiO2 Photocatalysis

Abstract
Plasmonic phenomena have greatly contributed to nanooptics and nanophotonics owing to their features such as light localization and high sensitivity to the surrounding environment.[1] The nanoparticles of poor metals (e.g. Al, In) exhibit plasmonic properties in the UV range (240-350 nm) where many organic molecules and semiconductors absorb light, which was recently confirmed and utilized in enhanced Raman spectroscopy and gas sensing.[2,3] The present study demonstrates the efficient TiO2photocatalysis with poor metal (Al, In) nanostructures resonant in the deep- and near-UV range. Poor metal nanoparticles were distributed on a TiO2 thin film, where methylene blue (MB) was applied to monitor the photocatalytic activity. The photocatalytic reaction was initiated by irradiating the samples with UV light, and the time-dependent decay of the MB absorbance was observed. A reaction rate was found to increase by factors as high as 14 and 7 for Al and Innanoparticles, respectively. (see Fig. 1) The enhancement of photocatalysis shows particle size dependence. The increase and downward trend in the enhancement shows a good agreement with that in the field intensity simulated by the discrete dipole approximation (DDA). (see Fig. 2)