Light-induced coalescence of plasmonic dimers and clusters

Research output: Contribution to journalArticle

Authors

  • Andrew R. Salmon
  • Marie-Elena Kleemann
  • Junyang Huang
  • William M Deacon
  • Cloudy Carnegie
  • Marlous Kamp
  • Bart De Nijs
  • Jeremy J. Baumberg

Colleges, School and Institutes

External organisations

  • University of Cambridge
  • Cavendish Laboratory, Department of Physics
  • Nanophotonics Centre
  • Cavendish Laboratory

Abstract

The properties of nanoplasmonic structures depend strongly on their geometry, creating the need for high-precision control and characterization. Here, by exploiting the low activation energy of gold atoms on nanoparticle surfaces, we show how laser irradiation reshapes nanoparticle dimers. Time-course dark-field microspectroscopy allows this process to be studied in detail for individual nanostructures. Three regimes are identified: facet growth, formation of a conductive bridge between particles, and bridge growth. Electromagnetic simulations confirm the growth dynamics and allow measurement of bridge diameter, found to be highly reproducible and also self-limiting. Correlations in spectral resonances for the initial and final states give insight into the energy barriers for bridge growth. Dark-field microscopy shows that coalescence of multiple gaps in nanoparticle clusters can be digitally triggered, with each gap closing after discrete increases in irradiation power. Such control is important for light-induced nanowire formation or trimming of electronic and optoelectronic devices.

Details

Original languageEnglish
Number of pages6
JournalACS Nano
Early online date25 Mar 2020
Publication statusPublished - 1 Apr 2020

Keywords

  • gold nanoparticles, plasmonics, nanoparticle dimers, nanoparticle coalescence, sintering, optical spectroscopy