Web Release Date: March 21,
Continuous Distribution of Emission States from Single CdSe/ZnS Quantum Dots
and
Department of Chemistry, University of California at Berkeley, and Materials Sciences Division and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
Received March 1, 2006
Abstract:
The photoluminescence dynamics of colloidal CdSe/ZnS/streptavidin quantum dots were studied using time-resolved single-molecule spectroscopy. Statistical tests of the photon-counting data suggested that the simple "on/off" discrete state model is inconsistent with experimental results. Instead, a continuous emission state distribution model was found to be more appropriate. Autocorrelation analysis of lifetime and intensity fluctuations showed a nonlinear correlation between them. These results were consistent with the model that charged quantum dots were also emissive, and that time-dependent charge migration gave rise to the observed photoluminescence dynamics.
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