Linking on-state memory and distributed kinetics in single nanocrystal blinking

Amy A. Cordones, Kenneth Knappenberger, Stephen R. Leone

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Memory effects in single nanocrystal fluorescence blinking are investigated as a function of the on-state kinetics for CdSe/ZnS quantum dots and CdSe nanorods. The on-state duration probability distributions for single nanocrystal blinking traces are characterized by an inverse power law, which crosses over to exponential decay for long on-state durations. The correlations of subsequent on-state durations (Rlog,on) are found to decrease for nanocrystals that display earlier crossover times and smaller power law coefficients. Specifically, Rlog,on increases from 0.14 ± 0.02 to a saturation value of 0.44 ± 0.01 for nanocrystals with average crossover times of ∼100 ms to more than 5.0 s, respectively. The results represent the first link between memory effects and blinking kinetics and are interpreted in the framework of two competing charge trapping mechanisms. A slow fluctuation-based trapping mechanism leads to power-law-distributed on durations and significant memory effects; however, the additional contribution of an ionization-induced trapping pathway is found to induce crossover to exponential decay and decreased memory. Monte Carlo simulations of nanocrystal blinking based on the two trapping mechanisms reproduce the experimental results, suggesting that the power law component and the memory effects correlate with a fluctuation-based mechanism. This effect is found to be universal, occurring for two nanocrystal morphologies and in blinking data measured using a wide range of continuous and pulsed excitation conditions.

Original languageEnglish (US)
Pages (from-to)4241-4248
Number of pages8
JournalJournal of Physical Chemistry B
Volume117
Issue number16
DOIs
StatePublished - Apr 25 2013

Fingerprint

blinking
Nanocrystals
nanocrystals
Data storage equipment
Kinetics
kinetics
trapping
crossovers
Charge trapping
decay
Nanorods
Probability distributions
nanorods
Semiconductor quantum dots
Ionization
Fluorescence
quantum dots
saturation
ionization
fluorescence

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Cite this

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abstract = "Memory effects in single nanocrystal fluorescence blinking are investigated as a function of the on-state kinetics for CdSe/ZnS quantum dots and CdSe nanorods. The on-state duration probability distributions for single nanocrystal blinking traces are characterized by an inverse power law, which crosses over to exponential decay for long on-state durations. The correlations of subsequent on-state durations (Rlog,on) are found to decrease for nanocrystals that display earlier crossover times and smaller power law coefficients. Specifically, Rlog,on increases from 0.14 ± 0.02 to a saturation value of 0.44 ± 0.01 for nanocrystals with average crossover times of ∼100 ms to more than 5.0 s, respectively. The results represent the first link between memory effects and blinking kinetics and are interpreted in the framework of two competing charge trapping mechanisms. A slow fluctuation-based trapping mechanism leads to power-law-distributed on durations and significant memory effects; however, the additional contribution of an ionization-induced trapping pathway is found to induce crossover to exponential decay and decreased memory. Monte Carlo simulations of nanocrystal blinking based on the two trapping mechanisms reproduce the experimental results, suggesting that the power law component and the memory effects correlate with a fluctuation-based mechanism. This effect is found to be universal, occurring for two nanocrystal morphologies and in blinking data measured using a wide range of continuous and pulsed excitation conditions.",
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Linking on-state memory and distributed kinetics in single nanocrystal blinking. / Cordones, Amy A.; Knappenberger, Kenneth; Leone, Stephen R.

In: Journal of Physical Chemistry B, Vol. 117, No. 16, 25.04.2013, p. 4241-4248.

Research output: Contribution to journalArticle

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