Tunable surface plasma resonance of gold nanorods superstructure and their SERS properties

Abstract

High-quality gold nanorods (GNRs) with different aspect ratios and uniform morphology were synthesised using the seed-mediated growth method. The GNRs were assembled into two different type superstructures: the one is arranged vertically to the substrate (V-GNR superstructure); the other is arranged parallel to the substrate (P-GNR superstructure). Their work at present is devoted to study the Raman enhancement effect and signal repeatability of GNR superstructures. The influence of GNRs arrangement on surface-enhanced Raman scattering (SERS) was investigated experimentally. In addition, the electromagnetic field coupling of GNR superstructures with different arrangement modes was simulated by the finite-different time-domain method. Both experiments and theories have proved that the required resonance wavelength of Raman laser can be obtained by adjusting the aspect ratio of GNRs. Furthermore, the P-GNR superstructure can bring high and repeatable SERS signal intensity of molecules compared with V-GNR superstructure and other nanostructures. It can be concluded that P-GNR superstructure is a good substrate mode for SERS technique.