Abstract

The need for environmentally sustainable sources of energy has driven new momentum to the research for materials that may allow efficient solar water splitting. Titania is a well studied material for water splitting since the discovery by Honda and Fujishima [1] but its large bandgap limits its use for solar applications. In the past various approaches have been tried up to now to increase the photocatalytic activity of titania, but all present major disadvantages. As an idea, recently metallic nanoparticles came to be recognized as good candidate to improve the visible light activity of titania, due to their interesting chemical and optical properties. In this work, we focused on the latter to take advantage of the intense near-field light that is originated near metallic nanoparticles when their localized surface plasmon resonances (LSPRs) are excited by incident light. This intense near-field light is deemed to induce two-photon absorption (TPA) in the titania nanocrystals deposited on the top of the gold nanoparticles (AuNPs) provided that the LSPR of the array corresponds to twice the wavelength of the titania bandgap.

© 2013 Japan Society of Applied Physics, Optical Society of America