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Elaboration et caractérisation structurale de nanocristaux moléculaires fluorescents inclus dans des couches minces sol-gel : Application à la réalisation de capteurs chimiques et biologiques.

Abstract : We optimized the elaboration of organic nanocrystals in sol-gel thin films obtained by spin-coating. This study focuses on sol preparation with precursors containing organic spacers to enhance sol-gel matrix porosity. Using various characterization techniques (fluorescence confocal microscopy, transmission electron microscopy) enables us to compare the nucleation and growth process of crystals obtained from free solutions with the space confinement involved in our nanocrystallization process in sol-gel matrices. We identified a great number of crystallized nanoparticles in our samples and obtained in some cases, their crystallographic system by electronic diffraction and by fluorescence microscopy resolved in polarization. We used time-resolved fluorescence spectroscopy to analyze nanocrystals properties as the signalization function of a chemical sensor. Indeed, adsorption of a probe molecule produces a fluorescence quenching of the nanocrystals. This quenching is all the more efficient because of crystalline order, that delocalizes the excitation on a great ratio of the 10^4 to 10^10 molecules of a nanocrystal. Modifying sol-gel matrix porosity, we optimized whether diffusion towards nanocrystals, whether nanocrystals protection against not specific interactions. Then, we showed potentialities of our samples as biological sensors.
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https://tel.archives-ouvertes.fr/tel-00263706
Contributor : Virginie Monnier <>
Submitted on : Thursday, March 13, 2008 - 9:44:28 AM
Last modification on : Friday, December 18, 2020 - 1:34:02 PM
Long-term archiving on: : Friday, May 21, 2010 - 12:24:38 AM

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  • HAL Id : tel-00263706, version 1

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Virginie Monnier. Elaboration et caractérisation structurale de nanocristaux moléculaires fluorescents inclus dans des couches minces sol-gel : Application à la réalisation de capteurs chimiques et biologiques.. Matériaux. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨tel-00263706⟩

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