Preparation and characterization of SiO2/Au core-shell nanopartieles

Gold nanolayer-encapsulated silica composite nanoparticles were synthesized by combining Au-surface seeding and a shell growing process. The composite particles were characterized and investigated by transmission electron microscopy (TEM) and UV-Visible absorption spectra. The results showed that the size distribution of the fabricated composite particles was narrow, gold nanoshells were smooth and complete, and the shell thickness could be controlled by varying the amount of the reactants. As the core radius-shell thickness ration was varied between 4 and 13, the optical resonance of these composite particles could move more than 500 nm in wavelength, across the visible and into the infrared region of the spectrum.