Transient absorption of titanium dioxide sputtered film deposited on two-dimensionally assembled gold nanoparticles

Two-layer film of titanium dioxide and gold nanoparticles was deposited onto glass substrate, and its extinction spectrum and transient absorption were measured. The gold nanoparticles (AuNPs) were deposited on silane-treated glass by wet process, which showed enhancement of optical absorption due to its surface plasmon resonance (SPR). On the AuNP self-assembly, the titanium dioxide was deposited by magnetron sputtering. The absorption spectra in the region of 400–600 nm suggested that the red-shift of plasmon band of the AuNP due to surrounding in the TiO2 film. Transient absorption study proved that the lifetime of the conductive electrons depended on the film thickness the of titanium dioxide layer.