Enhancing the fluorescence of individual thick shell CdSe/CdS nanocrystals by coupling to gold structures
Résumé
The fluorescence properties of individual CdSe/CdS nanocrystals
(NCs) with a very thick shell and deposited on metallic structures are analyzed in
detail. The results obtained for two metallic structures consisting of a continuous
or a semi-continuous gold film are compared. Under low pulsed excitation,
a strong acceleration of radiative processes is observed. The probability
of electron–hole pair recombinations through Auger processes dramatically
decreases, resulting in a suppression of blinking and the appearance of
biexcitonic cascades. An original method of photons postselection also enables
us to determine the decay rate corresponding to biexcitonic recombinations.
Finally, a detailed analysis of the excitation process and the photon collection
efficiency enables us to discriminate the effect of the gold structure in terms
of excitation and fluorescence acceleration. It is found that high collection
percentages can be achieved through the modification of NC emission with
plasmonic structures.
Domaines
Autre [cond-mat.other]
Origine : Fichiers éditeurs autorisés sur une archive ouverte
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