Temperature dependence of enhanced optical absorption and Raman spectroscopy from metallic nanoparticles

The temperature dependence of the optical/spectroscopic properties of metallic nanoparticles (in particular nanoshells) including absorption, scattering, and enhanced-Raman scattering for admolecules is studied via theoretical modeling. For core-shell particles, we focus on both the high frequency (symmetric) and low frequency (antisymmetric) plasmon resonance modes of the nanoshells. It is found, that while these properties in general have optimal values at a certain temperature specific to the shell configuration except for relatively thin shells, the SERS enhancement generally has more appreciable variations and decreases when the nanoshells get heated up from room temperature. Implications for various applications with these nanoparticles are discussed.