Two Mechanisms Determine Quantum Dot Blinking

Gangcheng Yuan, Daniel E. Gómez, Nicholas Kirkwood, Klaus Boldt, Paul Mulvaney

Research output: Contribution to journalArticleResearchpeer-review

149 Citations (Scopus)

Abstract

Many potential applications of quantum dots (QDs) can only be realized once the luminescence from single nanocrystals (NCs) is understood. These applications include the development of quantum logic devices, single-photon sources, long-life LEDs, and single-molecule biolabels. At the single-nanocrystal level, random fluctuations in the QD photoluminescence occur, a phenomenon termed blinking. There are two competing models to explain this blinking: Auger recombination and surface trap induced recombination. Here we use lifetime scaling on core-shell chalcogenide NCs to demonstrate that both types of blinking occur in the same QDs. We prove that Auger-blinking can yield single-exponential on/off times in contrast to earlier work. The surface passivation strategy determines which blinking mechanism dominates. This study summarizes earlier studies on blinking mechanisms and provides some clues that stable single QDs can be engineered for optoelectronic applications.

Original languageEnglish
Pages (from-to)3397-3405
Number of pages9
JournalACS Nano
Volume12
Issue number4
DOIs
Publication statusPublished - 24 Apr 2018
Externally publishedYes

Keywords

  • Auger recombination
  • photoluminescence intermittency
  • quantum dots
  • surface states

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