SIMULATED OPTICAL PROPRIETES OF GOLD-SILVER ALLOY NANOSHELL WITH DIFFERENT COMPOSITION.

In this paper the optical characteristics of the core-shell nanoparticles based on Au-Ag nanoshell core and materials silica shells are presented. Theoretical results on the optical characteristics gold-silver, as well as the measured properties of (Au-Ag)@SiO2 are investigated considered the surface plasmon resonance phenomenon associated with the surfaces of metals. This study allows us to determine the influences of the metal rate and silica thickness on the resonance plasmon surface. The profile of the resonance bands of a gold nanoparticle in contact with a silver metal is determined by the composition distribution of each metal. Discussion on the influence of various parameters (composition, thickness of shell?) on optical properties of nanoshell nanoparticles.The numerical simulationshowed that the resonance band is in visible region after silica coating on Au-Ag nanoparticles. A semiclassical theory (Mie theory) is used to study the optical behaviour of nanoshell nanoparticles. This theory is useful to improve resonance frequency to size ratio study at different percentage of gold and silver. However, the resonance frequency show an evolution toward weak wavelength and also according (Au-Ag)@SiO2nanospheres, results for these structure demonstrated potential applications in windows optical, because of high absorption cross section occurring in the wide band of visible spectrum