The synthesis, characterization, and molecular adsorption properties of colloidal silver–gold core–shell (Ag@Au CS) nanoparticles are reported. These nanoparticles are spherical in shape with a silver core and a uniform gold shell with potential applications in photothermal cancer therapies, drug delivery, and molecular sensing. Second harmonic generation (SHG) spectroscopic measurements are used to investigate the adsorption properties of malachite green, brilliant green, and methyl green to the surface of Ag@Au CS nanoparticles which are capped with mercaptosuccinic acid in an aqueous medium. The experimental adsorption isotherms obtained from SHG measurements are fit using the modified Langmuir model to obtain the free energies of adsorption and the adsorbate site densities. Difference extinction spectroscopy measurements show plasmonic and molecular resonance coupling which leads to a formation of new polaritonic states and Fano–type resonances with corresponding plasmon and molecular spectral depletions as the adsorbate concentration is increased. By investigation the dependence of the molecular resonance coupling under varying plasmonic spectra, important insight into polaritonic spectroscopy will be developed for improved molecular sensing and plasmon enhancement applications.

Molecular adsorption and resonance coupling at the colloidal silver–gold core–shell nanoparticle interface

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.