Monolithic NPG nanoparticles with large surface area, tunable plasmonics, and high-density internal hot-spots.

Plasmonic metal nanostructures have shown great potential in sensing, photovoltaics, imaging and biomedicine, principally due to the enhancement of local electric field by light-excited surface plasmons, i.e., collective oscillation of conduction band electrons.

Surface-enhanced Raman spectroscopy with monolithic nanoporous gold disk substrates.

Monolithic hierarchical nanoporous gold disks, 500 nm in diameter, 75 nm in thickness and 3.5 nm in pore radius, have been fabricated by hybrid processes. A surface-enhanced Raman scattering enhancement factor of at least 10(8) has been obtained on individual disks using benzenethiol self-assembled monolayer with 785 nm laser excitation.