Abstract

The localized surface-plasmon resonance absorption of metal nanoparticles is currently utilized in many fields such as near-infrared (NIR) curing and biomedical applications. In this paper, we study theoretically the influence of an oxide (${\mathrm{SiO}}_2$, ${\mathrm{ZrO}}_2$, or ${\mathrm{TiO}}_2$) shell on a metal (Ag, Au, or Cu) nanoparticle from the point of view of shifting the resonance peak to a more desirable color or NIR wavelengths while conserving the intensity of the absorption or extinction peak. The computational models used in the studies include the Mie theory and the four-flux method. We find shifts of up to hundreds or even close to 1000 nm. Among the material combinations studied, the largest shifts are obtained with $\mathrm{Ag}\text{-}{\mathrm{TiO}}_2$ core-shell nanoparticles when going from a few nanometers sized core without an oxide shell to a 100 nm size core with a 100 nm thick shell. However, the huge shifts happen together with severe intensity loss of the absorption peak, leading to a more conservative estimate of practically useful shifts of a few hundreds of nanometers.

© 2013 Optical Society of America

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