Silica-coated gold nanorod arrays for nanoplasmonics devices.

A facile method for growing silica layer on lithographically designed gold nanorod arrays (GNRAs) using a convenient sol-gel method is presented herein. The silica layer thickness was controlled on GNRAs with the reaction time. The localized surface plasmon resonance (LSPR) spectra of these hybrid metal/dielectric nanoparticles were recorded before and after the coating and the effect of different solvents on the LSPR were also assessed. The change in the fluorescence and SERS intensities of a probe molecule (Rh6G) deposited on GNRAs and silica-coated GNRAs revealed that the as-fabricated silica layer does inhibit the quenching of molecular excited states and enhances photophysical/photochemical processes. This kind of hybrid metal/dielectric nanoparticle arrays hence turn out to be real good candidates to design new "plasmonic-active" devices.