Synthesis of morphology controlled PtAu@Ag nanorings through concentric and eccentric growth pathways

We report the synthetic methodology for silver nanorings with controlled nanoscale morphology. The morphology of Ag nanorings was kinetically controlled by electrochemical potential tuning of Ag deposition using halide counter-ions, which resulted in concentric PtAu@Ag nanorings (i.e., Ag homogeneously wrapped around the Pt nanorings) and eccentric PtAu@Ag nanorings (i.e., Ag selectively deposited at the inner boundary of the Pt nanorings). The resulting high quality of each Ag nanoring allowed us to systematically investigate their corresponding localized surface plasmon resonance (LSPR) profiles as a function of their geometrical parameters. Additionally, we evaluated the application of the samples as surface-enhanced Raman spectroscopy (SERS) substrates composed of 2D monolayers of varied compositions of Ag and Au nanorings, which showed a different extent of enhancement depending on the adsorption characteristics of the analytes.

Automated summary

Silver nanorings with controlled morphology were synthesized by kinetically controlling the shape of Ag nanorings using electrochemical potential tuning. These nanorings showed different LSPR profiles depending on their geometric parameters, and were evaluated for use as SERS substrates composed of Ag and Au nanorings with varied compositions.