(Invited) A Versatile Plasmonic Film for Biosensing and Photocatalytic Applications

Wednesday, 31 May 2017: 08:30
Eglinton Winton (Hilton New Orleans Riverside)
Y. Yang (University of Central Florida)
Novel Au@TiO2 plasmonic films were fabricated by individually placing Au nanoparticles into TiO2 nanocavity arrays through a sputtering and dewetting process. These discrete Au nanoparticles in TiO2 nanocavities showed strong visible-light absorption due to the plasmonic resonance. Surface-enhanced Raman spectra (SERS) of this plasmonic film showed a high sensityvity to organic molecule at low concentration (down to 0.1 micro molar). Photoelectrochemical studies demonstrated that the developed Au@TiO2 plasmonic films exhibited significantly enhanced catalytic activities towards oxygen reduction reactions with an onset potential of 0.92 V (vs reversible hydrogen electrode), electron transfer number of 3.94, and limiting current density of 5.2 mA cm-2. The deposited Au film thickness remarkably affected the catalytic activities of Au@TiO2, and TiO2 coated with 5 nm Au (Au5@TiO2) exhibited the best catalytic function to reduce oxygen. The plasmon-enhanced reductive activity is attributed to the surface plasmonic resonance of embedded Au nanoparticles in TiO2 nanocavities and suppressed electron recombination.