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International Conference on Ultrafast Phenomena

Coulomb correlations, spectral line shapes, and size distributions of CdSe colloidal nanocrystals

Gregory D. Scholes, Margaret A. Hines, Mayrose R. Salvador

Published Jan 1, 2002• 0 citations
Publisher

Abstract

We report transient photon echo data for CdSe nanocrystals at 4.4K. The data and simulations, which include the effects of many-particle correlations, suggest that a significant contribution to the signal originates from an instrinsic inhomogeneity in the heavy-hole-type resonance energy. Our results indicate homogeneous line shapes that are consistent with those reported in single molecule studies.

DOI
10.1364/up.2002.tue31

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We report transient photon echo data for CdSe nanocrystals at 4.4K. The data and simulations, which include the effects of many-particle correlations, suggest that a significant contribution to the signal originates from an instrinsic inhomogeneity in the heavy-hole-type resonance energy. Our results indicate homogeneous line shapes that are consistent with those reported in single molecule studies.
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The fluorescence of single colloidal CdSe quantum dots is investigated at room temperature by means of the autocorrelation function over a time scale of almost 12 orders of magnitude. At short time, the autocorrelation function shows a complete antibunching indicating single photon emission and atomic-like behavior. On longer time scales (up to tens of seconds), we measure a bunching effect due to fluorescence intermittency that can not be described by fluctuations between two states with constant rates. The autocorrelation function also exhibits a non-stationary behavior related to power-law distributions of "On" and "Off" times.
The fluorescence of single-colloidal CdSe quantum dots is investigated at room temperature by means of the autocorrelation function over a time scale of almost 12 orders of magnitude. Over a short time scale, the autocorrelation function shows complete antibunching, indicating single-photon emission and atomiclike behavior. Over longer time scales (up to tens of seconds), we measure a bunching effect that is due to fluorescence intermittency and that cannot be described by fluctuations between two states with constant rates. The autocorrelation function also exhibits nonstationary behavior related to power-law distributions of On and Off times.