Surface Plasmon Enhanced Luminescence from Au covered Titania Nanotubes burned in a Methane Flame

Abstract

It is shown that coating by Au layers with thickness of 5 – 10 nm of titania nanotubes with anatase structure produced by burning the as-electrochemically-prepared nanotubes in a methane flame leads to the increase of the green photoluminescence intensity, while the effect of Ag coatings is insignificant. Titania nanotubes with average outer diameter of 150-200 nm and wall thickness of 60 nm were produced by anodization of Ti foils in an ethylene glycol based electrolyte containing a mixture of HF and H3PO4. The enhancement of the green emission is believed to be due to the effect of surface plasmons in Au coatings. This suggestion is supported by calculations of dispersion relations of surface plasmons at the Au/TiO2 interface and by the measurement of the transmission spectra of uncoated and metal coated titania nanotubes.