Effect of nickel on localized surface plasmon resonance activity of gold nanorods

Abstract

Extensive research over the past few years have shown that strong electromagnetic enhancements can be provided by noble metal nanostructures via the excitation of localized surface plasmons (LSPs) using light. This has sparked great interest in the field of harnessing the unique optical properties of one-dimensional metallic nanoparticles for SERS applications, especially in Au or Ag gapped nanorods as well as nanodisks arrays. In this project, the effect on the LSPR activity of Au nanorods by plasmonically inactive Ni nanorods in the UV-Vis-NIR spectrum range (331nm to 1100nm) was investigated. Ni-Au alloy compositional nanorods of various lengths were successfully fabricated by the bottom-up approach of electrodeposition into 300nm pore diameter sized anodized aluminum oxide (AAO) templates. The respective Ni- Au nanorods of different length were then analyzed for their extinction signals using the UV-Vis spectrometer and compared with the theoretical extinction signal peaks derived from the discrete dipole approximation (DDA) simulations. Experimental results confirmed that the plasmonic inactivity of Ni nanorods had caused damping of the LSPR signal of Au nanorods in the UV-Vis spectral range, resulting in reduced extinction intensity and broadening of the peak. This created difficulties in identifying red shifting of the peaks as postulated by the DDA simulation.