Coating time effect on surface structures of silica-encapsulated gold nanoparticles
This paper reports the silica density, surface structures and optical properties of gold nanoparticles coated with different thickness of silica shells. The gold nanoparticles encapsulated with amorphous silica shells were prepared in a slight modification of Stǒber method. The silica-shell thickness could be varied from 20 to 50 nm by controlling the experimental conditions, such as reaction time. Transmission Electron Microscopy (TEM) and UV-Visible absorption spectroscopy were employed to characterize the size, shell density, surface structures and the optical properties of these silica-coated gold nanoparticles. The TEM images demonstrated that the density of the silica shell were depended on the reaction time, and the surface morphology was changed from porous structures in the initial coating to the final continuous and smooth silica surface. With the increasing of the reaction time, the silica-coated gold nanoparticles became more and more round and monodispersed. UV-Vis spectra showed that surface plasmon absorption peak had a red-shifted of 3～12 nm on increasing the thickness of silica shell from 20 to 50 nm. A possible mechanism of silica formation on gold nanoparticles was proposed on the basis of silica shell density and the shift of absorption peak of coated gold nanoparticles.
Core-shell gold nanoparticles Silica shell Coating time Surface structure
Qin Qu Shantang Liu
School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology,Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan , 430074, China
国际会议
青岛
英文
935-938
2009-10-09（万方平台首次上网日期，不代表论文的发表时间）