Implications of sample aging on the formation of internally etched silica coated gold nanoparticles

Abstract

Aging time and storage conditions of silica stabilized gold nanoparticles impact the mechanism of nanoparticle-rattle structure formation. These differences are evaluated using electron microscopy and localized surface plasmon resonance spectroscopy coupled with modelling of gold nanosphere sensitivity to their local dielectric environment. Sample aging is revealed to impact the overall silica density and subsequent void formation in these structures. In all samples, voids formed near the metal cores and increased in size, which could be quantified using modelling. All in all, these results suggest that optimal silica membrane formation likely depends on initial silica density, which is directly related to sample age and storage conditions. As a result, these considerations as well as dielectric modelling could be exploited for future synthesis and use of these materials in surface enhanced spectroscopy and catalytic applications.