Plasmons in photocharged ZnO nanocrystals revealing the nature of charge dynamics

Jacob A. Faucheaux, Prashant Jain

Research output: Contribution to journalArticle

Abstract

Localized surface plasmon resonances (LSPRs), known for their fascinating optical properties, have thus far been limited to nanostructures of materials with high steady-state charge carrier densities. Here, we show that even a nonequilibrium charge population can support a LSPR mode. Photocharged zinc oxide (ZnO) nanocrystals show an infrared LSPR, which can be dynamically turned off by discharging via redox activity. It is deduced that the photoinduced LSPR is a collective mode of as few as four conduction band electrons, the least observed thus far. The sustenance of a free-electron plasma in charged ZnO, supported by the LSPR observation, leads us to propose the existence of a many-body excitonic state and suggest a mechanism for previously unresolved charge trapping dynamics in ZnO. The LSPR, which serves as an optical signature of a charged state of the nanoparticle, is also demonstrated as a useful probe of surface redox reactions.

Original languageEnglish (US)
Pages (from-to)3024-3030
Number of pages7
JournalJournal of Physical Chemistry Letters
Volume4
Issue number18
DOIs
StatePublished - Sep 19 2013

Fingerprint

Zinc Oxide
Plasmons
Surface plasmon resonance
Zinc oxide
plasmons
surface plasmon resonance
zinc oxides
Nanocrystals
nanocrystals
Charge trapping
Electrons
Redox reactions
electron plasma
Conduction bands
Charge carriers
free electrons
Carrier concentration
charge carriers
Nanostructures
conduction bands

Keywords

  • continuum exciton
  • defect luminescence
  • localized surface plasmon resonance
  • plasmonics
  • zinc oxide

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Plasmons in photocharged ZnO nanocrystals revealing the nature of charge dynamics. / Faucheaux, Jacob A.; Jain, Prashant.

In: Journal of Physical Chemistry Letters, Vol. 4, No. 18, 19.09.2013, p. 3024-3030.

Research output: Contribution to journalArticle

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