Soohyung Lee1 Vincent Holmberg1

1, University of Washington, Seattle, Washington, United States

Over the past decade, heavily-doped semiconductor nanostructures have emerged as an exceptionally powerful class of plasmonic materials due to the fact that their localized surface plasmon resonance frequency can be tuned greatly through changes in the density of free charge carriers, which can be controlled by the degree of doping, unlike metallic nanostructures which have nearly fixed charge carrier densities. In particular, copper chalcogenide nanocrystals have been studied widely in recent years because they exhibit an intrinsic plasmon band in the near infrared (NIR) spectral range. In the copper chalcogenides, localized surface plasmon resonances occur through the resonant excitation of high concentrations of free hole carriers in the valence band generated by large concentrations of copper vacancies present in the material. Herein, we investigate compositional tuning of the localized surface plasmon resonance frequency via careful control of the chalcogen composition for a set of small, isotropic copper chalcogenide nanocrystals with identical size, and also quantitatively evaluate their photothermal transduction efficiency. Moreover, we investigate changes in the plasmon response via control of shape and polarizability, as well as through gradual incorporation of metallic impurities in isotropic colloidal copper chalcogenide nanocrystals.