Metal-enhanced fluorescence from copper substrates

In this letter, the authors report the observation of metal-enhanced fluorescence emission from fluorophores deposited on copper (Cu) substrates. Different thicknesses of Cu particulate films (from 1 to $5\mathrm{nm}$ ) were deposited onto glass slides using thermal vapor deposition. Fluorophores positioned in close proximity to the Cu films show fluorescence enhancement as a function of the Cu thickness increases, reaching a maximum (2.5-fold) at $\approx 3\mathrm{nm}$ . The findings strongly suggest that surface plasmons from Cu can radiate and therefore enhance a fluorophore’s spectral properties, similar to observations reported for both silver and gold nanoparticle deposited substrates.