Excellent surface enhanced Raman scattering obtained with nanoporous gold fabricated by chemical de-alloying

Abstract

Three dimensional nanoporous gold, with an average ligament size of 50nm, was fabricated by chemical de-alloying from a new Au based metallic glass precursor. The resultant nanoporous gold gives rise to superior surface enhanced Raman scattering (SERS) capability using 4,4′-bi-pyridine as probe molecules. The SERS intensity mapping images confirm the presence of hot spots. A low detection limit down to 10−14M for bipyridine was achieved, which is attributed to the localized enhanced electromagnetic fields around nano-sized ligaments, the electromagnetic coupling between ligaments, and the trapped SERS sensitive atoms.