Time effect on the red shift of surface plasmonic resonance core-shell SiO2: Gold nanoparticles (AuNPs)

Spherical gold nanoparticles (AuNPs) chemically synthesized by Turkevich method, it coated with sodium silicate stock solution (Na2SiO3). Study different rate effect (SiO2 and ethanol) on position of surface plasmon resonance (SPR) of gold nanoparticles (AuNPs) after coated by using UV–Vis absorption spectroscopy. UV–vis spectrum showed that rate (SiO2 and ethanol) had effect in the coated gold nanoparticles (AuNPs), that Peak band gold nanoparticles (AuNPs) uncoated at (515nm) and this peak was shifted to longer wavelength (518nm) after coating. Coated after get a little shift in position of surface plasmon resonance (SPR) this means that coated method has an important role in maintain on gold nanoparticles (AuNPs) stability.