Control of Localized Surface Plasmon Resonances in Metal Oxide Nanocrystals

Abstract

Metal oxides, when electronically doped with oxygen vacancies, aliovalent dopants, or interstitial dopants, can exhibit metallic behavior due to the stabilization of a substantial charge carrier concentration within the material. As a result, localized surface plasmon resonances (LSPRs) occur in nanocrystals of conducting metal oxides. Through deliberate choice of both the host material and the defect, these resonances can be tuned across the entirety of the near- and mid-infrared regions of the electromagnetic spectrum. Optical modeling has revealed that the defects present have profound impacts on charge carrier mobility and electronic structure, and in some cases, choosing one dopant over another is an important trade-off for optimizing plasmonic performance. These materials are distinct from classical metals in that one can tune their LSPR in energy and intensity through their elemental composition independently of any particular size or nanocrystal morphology. In addition, the LSPR in these materials is highly modulable through external stimuli over substantial spectral windows. As a result, these materials uniquely provide a responsive plasmonic material that can offer optimal nanocrystal arrangements and morphology without compromising the intended resonance frequency for light concentration at any infrared wavelength.