Synthesis and Raman Performance Enhancement of Multilayer AuAg Heterostructures with Magnetic Resonance

Significant amplification of surface enhanced Raman scattering(SERS)signals can be achieved mainly by the electric field en-hancement in metal core-shell nanostructures,and the enhanced magnetic field is rarely studied.In this study,we prepared multi-gap Au/AgAu core-shell hybrid nanostructures by using gold nanocup as the core.The overgrowth processes to grow one,two,and three layers of AgAu hybrid nanoshells can produce Au/AgAu1,Au/AgAu2,and Au/AgAu3 heteronanostructures.The strong plasmon coupling between the core and shell leads to significant electromagnetic field enhancement.Under the synergistic effect of electromagnetic plasmon reso-nance and plasmon coupling,Au/AgAu core-shell hybrid nanostructures exhibit excellent SERS signals.We also investigate the effect of the interstitial position of the rhodamine B(RhB)molecule on Raman enhancement in Au/AgAu3 heteronanostructures.This study can pro-vide new ideas for the synthesis of multi-gap Raman signal amplifiers based on magnetic plasmon coupling.