The Effect of Silica Coating on the Optical Response of Sub-micrometer Gold Spheres
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- 作者：Jessica Rodrí ; guez-Ferná ; ndez ; Isabel Pastoriza-Santos ; Jorge Pé ; rez-Juste ; F. Javier Garcí ; a de Abajo ; Luis M. Liz-Marzá ; n
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：September 13, 2007
- 年：2007
- 卷：111
- 期：36
- 页码：13361 - 13366
- 全文大小：294K
- 年卷期：v.111,no.36(September 13, 2007)
- ISSN：1932-7455
文摘
The effects derived from the growth of silica shells on the optical properties of sub-micrometer gold sphereshave been investigated as a function of shell thickness. The dipole plasmon resonance mode of these largespheres has been found to be significantly more sensitive to changes in the medium refractive index than thequadrupolar mode, in agreement with theoretical modeling based on the boundary element method (BEM)for concentric spheres. Near-field maps of both resonance modes in such coated nanoparticles show that theareas with significant near-field enhancement get progressively located within the silica shell as its thicknessincreases, with basically no enhancement outside of the shell when this is thicker than the sphere radius.