Abstract
In this work, we characterize the near-field response of individual gold nanotriangles over a broad, visible-to-infrared, spectral region (200-1500 meV) using high-resolution electron energy-loss spectroscopy (EELS) performed inside of a scanning transmission electron microscope (STEM). We begin by experimentally imaging the spatial and spectral extent of each nanotriangle’s plasmonic Fabry-Pérot modes and measuring the evolution of their resonance energies with increasing edge length; thereby providing detailed information on infrared plasmon dephasing times and dispersion relations. Numerical electromagnetic simulations of the electron probe are used to interpret these experimental results and to compare the near-field electromagnetic enhancement factors of gold nanotriangles and nanorods of equal resonant energy. Taken together, this combined experimental and theoretical study provides unique insights relevant to designing noble metal plasmonic nanoparticle systems for solar energy harvesting and sensing applications in the near- and mid-infrared.
| Original language | English |
|---|---|
| Pages (from-to) | 6777-6784 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry C |
| Volume | 127 |
| Issue number | 14 |
| DOIs | |
| State | Published - Apr 13 2023 |
Funding
This material is based upon work supported by the Air Force Office of Scientific Research under Award FA9550-21-1-0282 (V.K., A.W.R, D.J.M., J.P.C.). The NT synthesis work is supported by an award to S.N. from the National Science Foundation, Division of Chemistry, Macromolecular, Supramolecular, and Nanochemistry (MSN) Program under Grant No. CHE2107728 (Z.R.L., R.D.N., S.N.). STEM-EELS experiments were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility (J.A.H.). This research was conducted, in part, using instrumentation within ORNL’s Materials Characterization Core provided by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the DOE, and sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy.