Silicon dioxide covered Au and Ag nanoparticles for shell-isolated nanoparticle enhanced spectroscopies in the near-infrared

Abstract

The present work reports the extension of the SHINERS and SHINEF (shell-isolated nanoparticles enhanced Raman scattering, and fluorescence, respectively) effects into the near-infrared excitation, at 1064 nm and 785 nm, respectively. Plasmon enhanced effects were obtained for the SHIN Au@SiO₂ and Ag@SiO₂ nanoparticles. The overall SHINERS performance of both SHIN in the presence of the probe dye IR-820 is considerably lower than for the visible region of the spectra, and the conjunction to the IR-820 dye has been essential for the observation of SHINERS. The SHINEF performance for both SHIN excited at 785 nm is quite similar; this similarity is assigned to the similar values of quality factor for the two coinage metals in that region of the electromagnetic spectrum.