Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots

Christophe Galland, Yagnaseni Ghosh, Andrea Steinbrück, Milan Sykora, Jennifer A. Hollingsworth, Victor I Klimov, Han Htoon

Research output: Contribution to journalArticle

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Abstract

Photoluminescence blinking-random switching between states of high (ON) and low (OFF) emissivities-is a universal property of molecular emitters found in dyes, polymers, biological molecules and artificial nanostructures such as nanocrystal quantum dots, carbon nanotubes and nanowires. For the past 15 years, colloidal nanocrystals have been used as a model system to study this phenomenon. The occurrence of OFF periods in nanocrystal emission has been commonly attributed to the presence of an additional charge, which leads to photoluminescence quenching by non-radiative recombination (the Auger mechanism). However, this 'charging' model was recently challenged in several reports. Here we report time-resolved photoluminescence studies of individual nanocrystal quantum dots performed while electrochemically controlling the degree of their charging, with the goal of clarifying the role of charging in blinking. We find that two distinct types of blinking are possible: conventional (A-type) blinking due to charging and discharging of the nanocrystal core, in which lower photoluminescence intensities correlate with shorter photoluminescence lifetimes; and a second sort (B-type), in which large changes in the emission intensity are not accompanied by significant changes in emission dynamics. We attribute B-type blinking to charge fluctuations in the electron-accepting surface sites. When unoccupied, these sites intercept 'hot' electrons before they relax into emitting core states. Both blinking mechanisms can be electrochemically controlled and completely suppressed by application of an appropriate potential.

Original languageEnglish
Pages (from-to)203-207
Number of pages5
JournalNature
Volume479
Issue number7372
DOIs
Publication statusPublished - Nov 10 2011

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Blinking
Quantum Dots
Luminescence
Nanoparticles
Electrons
Nanowires
Carbon Nanotubes
Nanostructures
Genetic Recombination
Polymers
Coloring Agents

ASJC Scopus subject areas

  • General

Cite this

Galland, C., Ghosh, Y., Steinbrück, A., Sykora, M., Hollingsworth, J. A., Klimov, V. I., & Htoon, H. (2011). Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots. Nature, 479(7372), 203-207. https://doi.org/10.1038/nature10569

Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots. / Galland, Christophe; Ghosh, Yagnaseni; Steinbrück, Andrea; Sykora, Milan; Hollingsworth, Jennifer A.; Klimov, Victor I; Htoon, Han.

In: Nature, Vol. 479, No. 7372, 10.11.2011, p. 203-207.

Research output: Contribution to journalArticle

Galland, C, Ghosh, Y, Steinbrück, A, Sykora, M, Hollingsworth, JA, Klimov, VI & Htoon, H 2011, 'Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots', Nature, vol. 479, no. 7372, pp. 203-207. https://doi.org/10.1038/nature10569
Galland C, Ghosh Y, Steinbrück A, Sykora M, Hollingsworth JA, Klimov VI et al. Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots. Nature. 2011 Nov 10;479(7372):203-207. https://doi.org/10.1038/nature10569
Galland, Christophe ; Ghosh, Yagnaseni ; Steinbrück, Andrea ; Sykora, Milan ; Hollingsworth, Jennifer A. ; Klimov, Victor I ; Htoon, Han. / Two types of luminescence blinking revealed by spectroelectrochemistry of single quantum dots. In: Nature. 2011 ; Vol. 479, No. 7372. pp. 203-207.
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