Tunable SERS Platforms from Small Nanoparticle 3D Superlattices: A Comparison between Gold, Silver, and Copper
Résumé
Herein we present new substrates for surface-enhanced Raman
spectroscopy (SERS). The synthesis of colloidal nanoparticles
through an organometallic route allowed us to obtain gold,
silver, or copper nanoparticles with well-controlled shapes and
sizes (5–12 nm in diameter). The organization of these nanoparticles
into large-scale 3D superlattices produces a very large
number of “hot spots” at the origin of the signal enhancement.
Each superlattice was studied individually to correlate its optical
and SERS properties to the thickness, the nanoparticle
sizes, and the interparticle distance. This experimental and theoretical
study provides insights for the optimization and
tuning of the SERS activity. Indeed, significant SERS amplification
could be observed regardless of the nature of the metal.
In addition, the SERS signal was homogeneous at the surface
of the superlattices, which opens the route for a new approach
in analytical SERS detection.