Effect of shell thickness on a Au–Ag core–shell nanorods-based plasmonic nano-sensor

In this paper, Au–Ag core–shell nanorods were synthesized with the wet-chemical method, by which localized surface plasmon resonance (LSPR) wavelengths were tuned from 766 to 544 nm by controlling the thickness of the silver shell. The sensing ability of these core–shell nanorods was experimentally investigated by measuring the extinction spectra, which gives out the shift of LSPR wavelength as the refractive index of the surrounding medium changes. Experimental results show that the refractive index sensitivity (RIS) and figure of merit (FOM) of the core–shell nanorods can be increased at a certain thickness of the silver shell.