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ABSTRACT
Fluorescent semiconductor nanocrystals (quantum dots-QDs) exhibit very interesting optical properties : no photobleaching of their fluorescence over time (even under continuous excitation), narrow spectral width, easily tunable emission wavelength according to their size and chemical composition. However, their use remains limited : at a single particle level, their fluorescence fluctuates with time (blinking). A new type of quantum dots has been synthesized, with a strongly reduced blinking. This article presents the mechanisms of fluorescence and blinking of QDs, the general methods of synthesis, and the study of non-blinking nanocrystals with 100 % quantum yield at low temperature.
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Read the articleAUTHORS
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Michel NASILOWSKI: PhD student, University of Paris VI, LPEM/ESPCI, 10, rue Vauquelin, 75005 Paris, France
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Benoît DUBERTRET: Research Director, CNRS, LPEM/ESPCI, 10, rue Vauquelin, 75005 Paris, France
INTRODUCTION
Box 1 – History
The scientific community has been interested in semiconductor nanocrystals for some thirty years. Since their discovery in the early 1980s by Ekimov and Henglein , and their theoretical study by Efros and Brus , the synthesis protocols were improved and, in 1993, the first synthesis of size-controlled colloidal semiconductor nanocrystals was achieved. . Since this key synthesis, the field has undergone significant development, particularly since 2000, when new precursors that are less hazardous for synthesis were developed. . Since then, nanocrystals have been engineered: the band alignments of the various materials, the core/shell systems, etc., have all been designed and engineered. ... have made it possible to obtain materials with finely controllable physico-chemical properties, whose applications are now emerging on an industrial scale.
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KEYWORDS
State of the art | single particle spectroscopy | synthesis of colloidal nanoparticles | luminophores in display devices | fluorescent markers for biomedical imaging | quantum dots | blinking | quantum yield
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Nanosciences and nanotechnologies
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Non-flashing fluorescent nanocrystals: towards the perfect fluorophore
Properties of colloidal fluorescent semiconductor nanocrystals
Bibliography
Events
30 Years QDs – International conference celebrating 30 years of the discovery of colloidal QDs: May 26-28, 2014, ESPCI, Paris
( http://www.30-years-qds.com )
International Conference on Quantum Dots – International Conference on QDs, biannual
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Laboratoire de physique et d'étude des matériaux (LPEM, UMR8213 CNRS/UPMC/ESPCI), 10, rue Vauquelin, 75005 Paris, France
Organic & Hybrid Molecular Electronics Laboratory...
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