PERSONAL DE APOYO
MARCHI Maria Claudia
congresos y reuniones científicas
Título:
SYNTHESIS OF CdS AND CdSe NANOPARTICLES IN SELF-ORGANIZED MESOPOROUS FILMS OF SiO2 AND TiO2
Autor/es:
MARCHI, MARÍA CLAUDIA; MANZINI, AYELÉN; ALDABE BILMES, SARA
Lugar:
San Carlos de Bariloche, Argentina
Reunión:
Workshop; US-Argentina Workshop on nanomaterials, nanoMAT09; 2009
Institución organizadora:
Bilateral USA-Argentina Research and Development Projects on Nanotechnology
Resumen:
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The absorption and
luminescence of CdX (X=S or Se) nanoparticles (NPs) can be tuned with the
particle size and dielectric constant of surrounding medium. However, little is
known of these properties when CdX NPs are embedded in mesoporous arrays. On
the other hand, mesoporous oxides (MPO) are easily prepared by combining supramolecular
self-organization of amphiphilic molecules and sol-gel process for MO2,
a method giving the possibility of tuning pore and wall sizes by changing the
molecular template.
In this work we exploit the structure of MPO
films (SiO2 or TiO2) as matrix for inclusion of CdX NPs.
Our goal is the encapsulation of toxic NPs maintaining their optical properties
in long term.
The synthesis of NP arrangements in MPO
matrices was performed by sequential immersion in solutions containing
precursors of Cd and S or Se, or by dipping in suspensions of monodispersed NPs
with diameters smaller than the cavities in the matrix. The structure of the
MPO was tuned by the amphiphilics used as template.
Experiments done with different matrices gave
an intense and stable luminescence, being the emission band broader than that
found for a suspension of NPs. The luminiscence intensity is influenced by the
structure of the assembly, with vanishing signal for disordered films. Although
in some cases there is a significant contribution from the emission of surface
states, all samples exhibit a reproducible signal for several months.