Abstract

We report borrowed surface-enhanced Raman scattering (SERS) at Pd and Pt films deposited on Au sphere segment void (SSV) SERS substrates and show that ultrathin, pinhole-free Pd and Pt films could be easily achieved by choosing constant-current deposition for the Pd deposition and under-potential deposited Cu-mediated deposition for the Pt deposition. The surface enhancement achieved from the Pd and Pt films was reproducible, owing to the ordered SSV structure of their surfaces, and borrowed additional enhancement from the long-range electromagnetic (EM) fields generated by the underlying Au SSV substrate. SERS experiments and theoretical simulations indicate that the distance over which the EM fields generated by a concave Au SSV surface can be transferred to the surface of the transition-metal films is approximately an order of magnitude larger than that for a convex sphere surface. This longer range of the EM fields allowed deposition of thicker, more robust Pd and Pt films while retaining the borrowed enhancement. These properties make such Pd and Pt films attractive as SERS surfaces to reveal surface species and reactive intermediates on these two typical electrocatalyst materials.