Abstract:The fabrication and characteristics of spindle Fe₂O₃@Au core/shell particle were investigated, and the effect of the core/shell nanoparticles as the surface enhanced Raman spectroscopy (SERS)-active substrates was studied. By using the seed-catalyzed reduction technique, anisotropic Fe₂O₃@Au core/shell particles with spindle morphology were successfully prepared. The Fe₂O₃ particles with spindle morphology were initially prepared as original cores. The Au nanoparticles of 2 nm were attached onto the Fe₂O₃ particles through organosilane molecules. Uniform Au shell formed onto Fe₂O₃ core modified by Au nanoparticles through the in-situ reduction of HAuCl₄. The shell thickness was controlled through regulating the concentration of HAuCl₄ solution. The results of TEM, XRD and UV-vis characterization show that the core/shell particles with the original shape of the Fe₂O₃ particles are obtained and these surfaces are covered by Au shell completely. The surface enhanced Raman spectrum of the probe molecules adsorbed on these core/shell substrates is strong and the intensity is enhanced with the increase of the thickness of Au shell or the aspect ratio of particles. The spindle Fe₂O₃@Au core/shell particles exhibit optimum (SERS) activity.

Key words: surface enhanced Raman spectroscopy; Fe₂O₃@Au particle; spindle shape; thiophenol