Precise regulation and control of hotspots in nanoparticle multilayer SERS substrates

Precise regulation and control of the SERS active hotspot is a significant challenge in SERS technology. This study proposes the precise control of SERS active hotspots in multilayer substrates by combining metal nanoparticles with different dielectric constants. The hotspots of the multilayer SERS substrate composed of different nanoparticle monolayers (Ag, Au, Cu) were investigated by finite element simulation. It was found that the local field hotspots could be transferred controllably between different layers by using heterogeneous nanoparticle multilayer structures. Six multilayer SERS substrates composed of Ag nanoparticle (AgNP) and Au nanoparticle (AuNP) monolayer were fabricated via a layer-by-layer deposition method. The hotspots were precisely probed by the SERS signal of the reporter molecules adsorbed on a specific position. SERS test results showed that the hotspots could be transferred efficiently between layers by combining different metal nanoparticle monolayers, consistent with the simulation results. The results presented in this manuscript strengthen the understanding of surface plasmon on nanoparticle multilayer systems and have profound importance in surface analysis.

Automated summary

This study proposes a method to precisely control SERS active hotspots in multilayer substrates by combining metal nanoparticles with different dielectric constants. The hotspots of the multilayer SERS substrate composed of different nanoparticle monolayers were investigated by simulation and experiment. The results showed that the hotspots could be transferred controllably between different layers by using heterogeneous nanoparticle multilayer structures, which has profound importance in surface analysis.