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|title: ||Photoluminescent, transparent and flexible di-ureasil hybrids containing CdSe/ZnS quantum dots|
|authors: ||Neves, Marcia C.|
Martins, Manuel A.
Soares-Santos, Paula C. R.
Ferreira, Rute A. S.
Carlos, Luís D.
|issue date: ||Apr-2008|
|publisher: ||Institute of Physics|
|abstract: ||We describe, in this paper, the sol–gel synthesis of di-ureasil based nanocomposites prepared in
situ in the presence of organically capped CdSe quantum dots (QDs) or CdSe QDs which have
been coated with a ZnS shell. For the latter a new chemical route to coat the CdSe QDs with
ZnS shells was investigated and is now reported. The QDs became well dispersed in the final
nanocomposites, whose microstructural homogeneity was evaluated by atomic force
microscopy (AFM) and transmission electron microscopy (TEM) analyses. In order to
understand the optical behaviour of di-ureasil containing QDs, a detailed photoluminescent
study was undertaken for a selected particle size distribution of ZnS coated CdSe QDs
(d ∼ 4.5 nm). Emission quantum yields up to 0.11 were measured in the final nanocomposites
that present a huge (between 3 and 6 orders of magnitude) increase in the lifetime of the QDs
(relative to that of isolated ones), as a result of energy transfer occurring between the intimately
mixed di-ureasil host and the QDs.|
|appears in collections||CICECO - Artigos|
FIS - Artigos
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