Morphological control and plasmonic tuning of nanoporous gold disks by surface modifications

Abstract

We report a surface modification protocol to control nanoporous gold (NPG) disk morphology and tune its plasmonic resonance. Enlarged pore size up to ∼20 nm within 60 s dealloying time has been achieved by adsorbing halides onto alloy surfaces in-between two dealloying steps. In addition, plasmonic resonance has been significantly red-shifted by up to ∼258 nm by the surface modification. Furthermore, with the enlarged pore size, small gold nanoparticles have been effectively loaded into the pores to enhance the performance of surface-enhanced Raman scattering (SERS) due to hot spot formation between the original nanoporous network and loaded nanoparticles.