Light emissions from nanoparticles

Plasmons decay non-radiatively generating an excited electron-hole pair or radiatively. By optically monitoring changes to the radiative pathway of a single particle, carrier relaxation dynamics can be obtained with the ultimate goal of obtaining information about the nanoscale environment including chemical reactions. Unlike in semiconductors, where large bandgaps enable long carrier lifetimes, excited electrons and holes in metals relax much more quickly due to the large density of states. Despite this difficulty, emission spectroscopy of metal nanoparticles is possible on the single particle level because of the absence of photobleaching.

The goal of the Link Research Group is to apply steady-state and time-resolved emission spectroscopies to characterize hot carrier generation and subsequent transfer to electron and hole acceptors, possibly revolutionizing how we currently think about photocatalysis. Specifically, we have established quantitative analysis methods extract absolute emission quantum yields for colloidal nanoparticles and lithographically prepared nanostructures through detailed correlation with electron microscopy and electromagnetic modeling. Applying our understanding of isolated plasmonic nanoparticles to heterostructures that consist of a plasmonic core and a semiconducting interface has allowed us follow interfacial charge transfer. Recently, we have also studied the emission properties of single carbon dots to understand the number and chemical identity of their chromophores.

Selected publications:

  1. S. A. Lee, C. T. Kuhs, E. K. Searles, H. O. Everitt, C. F. Landes, and S. Link, d-Band Hole Dynamics in Gold Nanoparticles Measured with Time-Resolved Emission Upconversion Microscopy, Nano Lett., 23, 8, 3501–3506 (2023)
  2. Z. Bian, A. Wallum, A. Mehmood, E. Gomez, Z. Wang, S. Pandit, S. Nie, S. Link, B. G. Levine, and M. Gruebele, Properties of Carbon Dots versus Small Molecules from “Bottom-up” Synthesis, ACS Nano, 17, 22, 22788–22799 (2023)
  3. E. K. Searles, E. Gomez, S. A. Lee, B. Ostovar, S. Link, and C. F. Landes, Single-Particle Photoluminescence and Dark-Field Scattering during Charge Density Tuning, J. Phys. Chem. Lett., 14, 2, 318–325 (2023)
  4. S. A. Lee, B. Ostovar, C. F. Landes, and S. Link, Spectroscopic signatures of plasmon-induced charge transfer in gold nanorods, J. Chem. Phys., 156 (5), 064702 (2022)
  5. Y.-Y. Cai, L. J. Tauzin, B. Ostovar, S. Lee, and S. Link, Light emission from plasmonic nanostructures, J. Chem. Phys., 155, 060901 (2021)