Nano-Ag on vanadium dioxide. I. Localized spectrum tailoring.

We report on the utilization of localized surface plasmon resonance (LSPR) of Ag nanoparticles to tailor the optical properties of VO2 thin film. Interaction of nano-Ag with incident light yields a salient absorption band in the visible-near IR region and modifies the spectrum of VO2 locally. The wavelength of modification occurs in a limited spectral region rather than affects the full spectrum. The wavelength of modification shows a strong dependence on the metal nanoparticle size and shifts toward the red as the particle size or the mass thickness of nano-Ag increases. Also, we found that the wavelength can be shifted into the IR further by introducing a thin layer of TiO2 onto the nano-Ag. Interestingly, with the help of LSPR effects the VO2 film exhibits an anomalous thermochromic behavior in the modification wavelength region, which may be useful in optical switching applications. [ABSTRACT FROM AUTHOR]