Gradual growth of gold nanoseeds on silica for SiO 2 @gold homogeneous nano core/shell applications by the chemical reduction method

Author： Nikabadi H Rezvani Shahtahmasebi N. Rokn-Abadi M Rezaee Mohagheghi M M Bagheri Goharshadi E.K.

Publisher： IOP Publishing

ISSN： 1402-4896

Source： Physica Scripta, Vol.87, Iss.2, 2013-02, pp. : 25802-25806

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Abstract

In this paper, a facile method for the synthesis of gold nanoseeds on the functionalized surface of silica nanoparticles has been investigated. Mono-dispersed silica particles and gold nanoparticles were prepared by the chemical reduction method. The thickness of the Au shell was well controlled by repeating the reduction time of HAuCl₄ on silica/3-aminopropyltriethoxysilane (APTES)/initial gold nanoparticles. The prepared SiO₂@gold core/shell nanoparticles were studied using x-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and ultraviolet visible (UV-Vis) spectroscopy. The TEM images indicated that the silica nanoparticles were spherical in shape with 100 nm diameters and functionalizing silica nanoparticles with a layer of bi-functional APTES molecules and tetrakis hydroxy methyl phosphonium chloride. The gold nanoparticles show a narrow size of up to 5 nm and by growing gold nanoseeds over the silica cores a red shift in the maximum absorbance of UV-Vis spectroscopy from 524 to 637 nm was observed.