Tuning the SERS activity of Au@Pd core-shell nanoparticles by controlling the thickness of the Pd shell

Abstract

Pinhole-free An core Pd shell (Au@Pd) nanoparticles with controllable size were synthesized, and the optical properties of the nanoparticles can be tuned by varying the size of the core and the thickness of the shell. The Au@Pd nanoparticles were characterized with TEM, HRTEM, UV-Vis absorption spectroscopy and SERS. Through a systematic study of the dependence of SERS activity of Au@Pd nanoparticles on the thickness of the Pd shell, it was found that the SERS activity of the Au@ Pd nanoparticles is much higher than the massive Pd electrode roughened using electrochemical method, which is owing to the long-range effect of the enhanced electromagnetic field of the Au core.