Turnability of the Plasmonic Response of the Gold Nanoparticles in Infrared Region

Abstract

We report on the modulation of the optical properties namely the Surface Plasmon Resonance (SPR) of gold nanoparticles core-shell as function of the surrounding medium (water, ethanol). We have study two different combinations (1) silica thin film coating gold nanospheres and (2) gold thin film coating silica nanoparticles. The optical model used is based on Mie theory by considering spherical gold nanoparticles core-shell and the simulation is done using Matlab program. The results show an important influence of the surrounding medium and the size of the core as well as the shell thickness, on the optical properties with a redshift of the Surface Plasmon Resonance (SPR). By using Mie theory and Drude model for the simulation of the Surface Plasmon Resonance model of spherical nanoparticles showed that for the control of the Surface Plasmon Resonance of the gold thin film coating silica nanoparticles it is important to considered three parameters (i) the size of core (ii) the surrounding medium and (iii) shell thickness, which enable the turning of the SPR through the near infrared; where as gold nanosphere coated by silica results has a maximum wavelength at 530 nm, this Plasmon peak corresponding a R1/d ratio of 1.6. Thus, this work enabled optimizing core-shell structure with well-controlled sizes for biomedical application.