Surface-enhanced Raman scattering on nanoporous Au

Colloidal solutions of metal nanoparticles are currently among the most studied substrates for sensors based on surface-enhanced Raman scattering (SERS). However, such substrates often suffer from not being cost-effective, reusable, or stable. Here, we develop nanoporous Au as a highly active, tunable, stable, biocompatible, and reusable SERS substrate. Nanoporous Au is prepared by a facile process of free corrosion of AgAu alloys followed by annealing. Results show that nanofoams with average pore widths of ∼250nm exhibit the largest SERS signal for 632.8nm excitation. This is attributed to the electromagnetic SERS enhancement mechanism with additional field localization within pores.