“Flash”
Synthesis of CdSe/CdS Core–Shell Quantum Dots
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Abstract
We report on the “flash”
synthesis of CdSe/CdS core–shell quantum dots (QDs). This new
method, based on a seeded growth approach and using an excess of a
carboxylic acid, leads to an isotropic and epitaxial growth of a CdS
shell on a wurtzite CdSe core. The method is particularly fast and
efficient, allowing the controllable growth of very thick CdS shells
(up to 6.7 nm in the present study) in no more than 3 min, which is
considerably shorter than in previously reported methods. The prepared
materials present state-of-the-art properties with narrow emission
and high photoluminescence quantum yields, even for thick CdS shells.
Additionally, Raman analyses point to an alloyed interface between
the core and the shell, which, in conjunction with the thickness of
the CdS shell, results in the observed considerable reduction of the
blinking rate