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Elaboration et caractérisation de vanadates de terres rares nanométriques : vers de nouveaux capteurs pour la détection de peroxyde d'hydrogène

Abstract : Over the past few years, civil security and the fight against terrorism have become critical issues, leading to a growing need for techniques to detect different threats and especially gas. In this context, the CEA is actively involved in the development of chemical gas sensors and in the elaboration of their sensitive materials. Due to the short lifetime of fluorescent organic materials, a need for robust sensitive materials exists. In light of these issues, this project focuses on the development of a sensitive inorganic material composed of fluorescent nanoparticles of rare earths vanadates synthesized by the sol-gel process. Innovative syntheses, with a fine control of the nucleation and crystallization steps, enable to reach significant performance such as the selective detection of the target gas at sub ppm levels, while guaranteeing a material lifetime of several months. In addition, a precise pH control ensures a good reproducibility of the syntheses. Finally, an excellent photostability of the particles was obtained by incorporating a microwave treatment into the synthesis.The particles were characterized by X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR) or thermoluminescence to better understand the mechanism of the detection of H2O2 vapors by the YVO4:Eu nanoparticles. A dynamic quenching of the particles fluorescence is associated with exposure to hydrogen peroxide. It seems to imply an action of H2O2 on the defects (such as oxygen vacancies), resulting in a transfer of energy from the excited state of Eu3+ ions to the defects, thus preventing the fluorescence emission.
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https://tel.archives-ouvertes.fr/tel-01127583
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Submitted on : Saturday, March 7, 2015 - 3:42:11 AM
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  • HAL Id : tel-01127583, version 1

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Natacha Duée. Elaboration et caractérisation de vanadates de terres rares nanométriques : vers de nouveaux capteurs pour la détection de peroxyde d'hydrogène. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2014. Français. ⟨NNT : 2014PA066446⟩. ⟨tel-01127583⟩

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