A simple Mie-type model for silica-coated gold nanocages

► Mie-type model describes the extinction spectra of gold nanocages (AuNCs).► Three-layered model adequately predicts the main spectral features of silica-coated AuNCs.► The silica shell thicknesses from the plasmonic shifts are in good agreement with TEM measurements.

Experimental extinction spectra of gold nanocages are much similar to those recorded for gold nanoshells on silica cores. This observation suggests that a simple spherically symmetrical Mie-type model can be applied to the prediction of extinction and scattering spectra for gold nanocage suspensions. Here, we show that such a model describes adequately not only extinction spectra of as-prepared gold nanocages but also experimental spectra and plasmonic resonance shifts for silica-coated gold nanocages. Furthermore, we demonstrate that the silica shell thicknesses, as determined from the plasmonic resonance shift, are in good agreement with the direct measurements based on transmission electron microscopy images.