title: The Interplay of Shape and Crystalline Anisotropies in Plasmonic Semiconductor Nanocrystals.
abstract: Doped semiconductor nanocrystals are an emerging class of materials hosting localized surface plasmon resonance (LSPR) over a wide optical range. Studies so far have focused on tuning LSPR frequency by controlling the dopant and carrier concentrations in diverse semiconductor materials. However, the influence of anisotropic nanocrystal shape and of intrinsic crystal structure on LSPR remain poorly explored. Here, we illustrate how these two factors collaborate to determine LSPR characteristics in hexagonal cesium-doped tungsten oxide nanocrystals. The effect of shape anisotropy is systematically analyzed via synthetic control of nanocrystal aspect ratio (AR), from disks to nanorods. We demonstrate the dominant influence of crystalline anisotropy, which uniquely causes strong LSPR band-splitting into two distinct peaks with comparable intensities. Modeling typically used to rationalize particle shape effects is refined by taking into account the anisotropic dielectric function due to crystalline anisotropy, thus fully accounting for the AR-dependent evolution of multiband LSPR spectra. This new insight into LSPR of semiconductor nanocrystals provides a novel strategy for an exquisite tuning of LSPR line shape.
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Jongwook
authors.initials: J
authors.lastname: Kim
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Ankit
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States.|Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich , Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland.|Empa-Swiss Federal Laboratories for Materials Science and Technology , Uberlandstrasse 129, 8600, Dubendorf, Switzerland.
authors.forename: Franziska
authors.initials: F
authors.lastname: Krieg
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States.|Department of Materials Science & Engineering, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Amy
authors.initials: A
authors.lastname: Bergerud
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Delia J
authors.initials: DJ
authors.lastname: Milliron
keywords: Doped semiconductor; metal oxide; nanorod; platelet; tungsten bronze