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:
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> 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.