Materiais hÃbridos formados por nanofilmes moleculares depositados sobre nanofilmes metÃlicos produzidos por processo bottom-up em substratos vÃtreos para uso como parte ativa de nanodispositivos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In the present work we are investigating a hybrid systems formed by a thermally evaporated molecular nanofilm of rare earth complex over a metallic thin film obtained by a bottom-up process. To produce the new hybrid, we have deposited the photonic Eu(btfa)3bipy complex on a glassy substrate containing a silver nanostructured film formed by thermal reduction of embedded silver ions followed by growth and migration of silver nanoparticles, up to the glass surface. The luminescence of the rare earth complex over the glassy substrate was monitored as a function of the annealing time at the glass transition temperature (Tg), and the self-assembled nanofilm growth, monitored by Atomic Force Microscopy (AFM). The glassy samples of two systems GAPAgF and GAPAgO were obtained by melting the raw materials in a resistive furnace, followed by a thermal treatment around the glass transition temperature (Tg) to produce the nanostructured silver film in the surface of the samples, presenting metallic appearance. The new active glass substrate GAPAgO has an enormous growth velocity of the silver nanofilm if compared with the active glass GAPAgF, previously studied. The growth of nanoparticles was followed by atomic force microscopy (AFM) as a function of annealing time in both systems, allowing a silver nanostructure growth with 100 nm size in only two minutes of thermal treatment. The activation energy E related to crystallization, and the frequency factor was calculated for three compositions of the system GAPAgO. The results indicate the instability of this glass related to the previous system GAPAgF. The surface morphology was evaluated as a function of atmosphere during thermal treatment. The system GAPAgO presents preferential geometry structures in the glass surface. Fluorescence measurements of the Eu3+ in the complex Eu(btfa)3 bipy were analyzed as a function of the time of annealing, showing better luminescence enhancement increasing the roughness of the sample surface. The photonic properties of the sample were analyzed, and the systems were characterized by DRX, AFM and XPS. The aim of this work is to use these news materials as active substrates for nanodevices

ASSUNTO(S)

processo bottom â up nanopartÃculas de prata quimica inorganica silver nanoparticles plÃsmons plÃsmons botom â up process

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