Tunable and broadband plasmonic absorption via dispersible nanoantennas with sub-10 nm gaps.

Plasmonic nanoparticles have traditionally been associated with relatively narrow absorption profiles. But, for many of the most exciting potential applications for these particles, such as solar energy applications, broadband absorption is desirable. By utilizing on-wire lithography, nanostructures which absorb light through the visible and near-IR portions of the electromagnetic spectrum can be synthesized.

Silver-based nanodisk codes.

We report a novel method for synthesizing silver-based nanodisk code (NDC) structures using on-wire lithography, where we employ milder synthetic and etching conditions than those used to synthesize the analogous gold structures. The silver structures exhibit stronger surface-enhanced Raman scattering signals than their Au counterparts at 633 and 532 nm excitation and, therefore, lead to lower limits of detection when used in the context of DNA-based detection assays. Finally, use of two enhancing nanostructured materials in one disk code dramatically increases the information storage density for encoding.