Plasmonic enhancement of dual mode fluorescence in a silver nano-antenna–ZnO:Er3+ hybrid nanostructure

Abstract

Tuning of surface plasmon resonance (SPR) of silver nanoparticles (Ag NPs) through shape tailoring make them frequency tunable multipolar optical nano antennas that can be harnessed for optical enhancements in a fluorophore placed in optimal proximity. Such SPR tuning has been achieved with Ag nano-hexagons in which enhancements in both down (under UV excitation) and up (under IR excitation) conversion fluorescence from rare earth Er³⁺–doped ZnO nanoparticles are realised. The near field generated by the pure Ag NPs and their hybrids under UV and IR incident light is simulated using a finite difference time domain method, and a direct correlation with the observed fluorescence enhancement is established.