Biosensing potential of three-layered gold–dielectric–gold nanoshells: sensitivity of interdistance of resonance light scattering peaks to the local dielectric environment

The resonance light scattering cross section of the three-layered gold–dielectric–gold nanoshell is calculated using the quasi-static theory. The results show that three-layered gold–dielectric–gold nanoshells have three types of resonance light scattering spectra under different geometrical parameters, which are explained using plasmon hybridization theory. In the common type containing two resonance light scattering peaks, the longer wavelength peak red-shifts while the shorter one blue-shifts as the refractive index of the physical environment increase. This physical environment dependent interdistance enhancing between the two peaks shows the potential of the three-layered gold–dielectric–gold nanoshells used as biosensor based on resonance light scattering. The followed calculations about the comparison of sensitivity to the local dielectric environment between the three- and two-layered gold nanoshells further verify that point. At last, the calculated results that the three-layered gold–dielectric–gold nanoshells with small inner core and thin outer gold shell have the highest sensitivity are also obtained.