Single gold nanorod charge modulation in an ion gel device

Sean S E Collins, Xingzhan Wei, Thomas G. McKenzie, Alison Funston, Paul C Mulvaney

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A reliable and reproducible method to rapidly charge single gold nanocrystals in a solid-state device is reported. Gold nanorods (Au NRs) were integrated into an ion gel capacitor, enabling them to be charged in a transparent and highly capacitive device, ideal for optical transmission. Changes in the electron concentration of a single Au NR were observed with dark-field imaging spectroscopy via localized surface plasmon resonance (LSPR) shifts in the scattering spectrum. A time-resolved, laser-illuminated, dark-field system was developed to enable direct measurement of single particle charging rates with time resolution below one millisecond. The added sensitivity of this new approach has enabled the optical detection of fewer than 110 electrons on a single Au NR. Single wavelength resonance shifts provide a much faster, more sensitive method for all surface plasmon-based sensing applications.
Original languageEnglish
Pages (from-to)6863-6869
Number of pages7
JournalNano Letters
Issue number11
Publication statusPublished - 9 Nov 2016


  • dark-field microscopy
  • Gold nanorods
  • ion gel
  • plasmonics
  • single particle spectroscopy
  • solid-state charging

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