Optical properties of core–shell structured Ag/SiO2 nanocomposites

Silver nanoclusters coated by SiO2 were synthesized by a reverse micelle technique to obtain a core–shell microstructure with tunable particle size less than 50 nm. The refractive indices of the Ag/SiO2 nanocomposites were calculated based on a theoretical model for binary composite materials which illustrated a strong correlation to the size of the metallic core and the dielectric shell. Dynamic light scattering analysis of the Ag/SiO2 nanocomposites revealed that the refractive index of the nanocomposites was about 2.40, which was well in the range predicted by theoretical modeling. Optical absorption spectra and silver quantum dot size induced color change of the Ag/SiO2 nanocomposites suspension were also investigated.