Saturation of two-photon excitation provides insight into the effects of a quantum dot blinking suppressant: A fluorescence correlation spectroscopy study

Romey F. Heuff, Michele Marrocco, David T. Cramb

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18 Citations (Scopus)


Quantum dots are now extensively used as luminescent tags for biological and chemical applications; however, their propensity to display intermittent luminescence (aka blinking) has limited their use in quantitative assays. Various surface active redox agents, such as β-mercaptoethanol, have been posited as antiblinking agents to help mitigate this challenge. We have examined the effect of β-mercaptoethanol on the luminescence intermittency of CdSe/ZnS quantum dots using fluorescence correlation spectroscopy. We find that β-mercaptoethanol lowers the quantum dot brightness and therefore lowers the probability of observing blinking but does not otherwise inhibit intermittent luminescence. Based on changes in fluorescence correlation data and excited-state lifetimes, we propose that the partitioning of β-mercaptoethanol onto the quantum dot surfaces increases nonradiative de-excitation rates. This behavior appears to be independent of the quantum dot surface passivation layer or the solution contents. © 2007 American Chemical Society.
Original languageEnglish
Pages (from-to)18942 - 18949
Number of pages8
JournalJournal of Physical Chemistry C
Issue number51
Publication statusPublished - 27 Dec 2007


All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

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