Light-assisted Selective Chemical Synthesis on Plasmonic Nanoparticles: Titanium Dioxide on Gold Nanostars

In this thesis, light-assisted crystallization of TiO2 on gold nanostars was investigated by using gold plasmonic nanoparticles as a nano-source of heat to induce forced hydrolysis of TiCl4 precursor. The frequency of localized surface plasmon resonance and absorption cross-sections were investigated using COMSOL. Using a multi-laser Raman setup, in-situ crystallization of TiO2 was observed under various laser frequencies and intensities on four different shapes of gold nanoparticles each with a unique plasmonic resonance frequency. The correlation between laser intensity, precursor concentration, and plasmonic resonance frequency of the nanoparticles with crystallization nature of TiO2 was investigated. Through careful control over the experimental conditions we demonstrate localized crystallization of anatase TiO2 in the valleys of gold nanostars as confirmed by transmission electron microscopy. Our findings offer a new approach to the synthesis of partially covered gold-TiO2 core-shell nanocomposites with promising implications for visible light photocatalytic applications.M.A.S.2017-11-26 00:00:0