Preparation of Silver/Silica Composite Core-shell Nanoparticles and Influence of Shell Thickness on Optical Properties

Abstract

Silver /silica composite core-shell nanoparticles( Ag@ SiO2) with different silica shell thickness were prepared by sol-gel technology. Their localized surface plasmon resonance( LSPR) properties and refractive index sensitivities( RIS) were studied. With increasing of silica shell thickness,LSPR peak first got a red-shift. When silica shell thickness was 65 nm,the maximal shift about 50 nm had been reached. With further increase of shell thickness,LSPR peak shown blue-shift. LSPR peak became illegible when the shell thickness reached 120 nm. We also observed that RIS of silver nanoparticles decreased with increasing shell thickness.