Polarization-Dependent Surface-Enhanced Raman Scattering Activity of Anisotropic Plasmonic Nanorattles

Plasmonic nanorattles composed of solid plasmonic core and porous and hollow plasmonic shell are a novel class of nanostructures that are highly attractive for surface-enhanced Raman scattering (SERS)-based chemical and biological sensing and bioimaging. In this report, we demonstrate the polarization-dependent SERS activity of cuboidal plasmonic nanorattles composed of a solid gold nanorod core and porous and hollow cuboidal shell. Plasmonic coupling between the gold nanorod core and porous and hollow cuboidal shell of the nanorattles results in a large electromagnetic (EM) enhancement at the interior of the nanorattles. Owing to the presence of internal electromagnetic hotspots, the polarization dependence of the plasmonic nanorattles was found to be markedly different compared to that of solid AuNR@Ag nanocuboids. Similar to most conventional anisotropic solid nanostructures, the AuNR@Ag nanocuboids exhibited a polarization-dependent SERS activity that is dominated by the sharp corners and edges. Conversely, the internal electromagnetic hotspot formed between the AuNR and porous shell of cuboidal nanorattle dominates the SERS activity of the anisotropic nanorattles. The results further our understanding of the SERS activity of this promising class of hollow nanostructures with internal electromagnetic hotspots and provide guidelines for the design of highly efficient SERS substrates based on these nanostructures.