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Verres et vitrocéramiques à base de chalco-halogénures dopés par des ions de terres rares pour la luminescence dans le visible

Abstract : The present work deals with the study of new chalco halide glass-ceramics doped with rare earth ions for visible luminescence. The effect of the addition of different alkali-halide into glasses belonging to the Ga2S3-GeS2 system has been studied with the aim to extend their transparency into the ultraviolet region. Glasses transparent over the visible range (400-750 nm) up to the mid infrared (11,5 μm) have been obtained in the Ga2S3-GeS2-CsCl system. Transparent and homogeneous glass-ceramics have been prepared from several base glasses varying the CsCl content in the Ga2S3-GeS2-CsCl system. Nanocrystals with homogeneous size and uniformly distributed in the amorphous matrix have been generated with reproducibility by appropriate heat-treatment. A structural study of the crystallization has been realized using X-ray diffraction and solid state nuclear magnetic resonance performed on the 71Ga and 133Cs nuclei. The nucleating agent character of gallium has been shown in the glassy matrix with the crystallization of the Ga2S3 phase. An improved mechanical behaviour has also been observed in the prepared composite materials. Rare-earth ion praseodymium Pr3+ and neodymium Nd3+) doped glass-ceramics have been synthesized in the Ga2S3-GeS2-CsCl system. The visible luminescence from r3+ and Nd3+ ions has been studied as a function of heat-treatment conditions. It appeared from experiments that Pr3+ ions are not incorporated into the crystals contrary to the Nd3+ ions from which an enhanced luminescence was observed, suggesting their partial integration into the crystalline phase. Finally, silver and Pr3+ doped glasses have been ynthesized in the Ga2S3-GeS2 system. Metallic silver nanoparticles were generated by heat-treatment at 370°C and characterized by transmission electronic microscopy. The influence of the NPs on the Pr3+ ions luminescence properties was studied by performing frequency up-conversion experiments. A large enhancement of the upconversion signal was observed in the presence of silver nanoparticles and attributed to the surface plasmonic resonance effect.
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Submitted on : Saturday, July 11, 2009 - 4:33:19 AM
Last modification on : Tuesday, January 12, 2021 - 4:40:05 PM
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  • HAL Id : tel-00403661, version 1

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Yannick Ledemi. Verres et vitrocéramiques à base de chalco-halogénures dopés par des ions de terres rares pour la luminescence dans le visible. Matériaux. Université Européenne de Bretagne, 2008. Français. ⟨tel-00403661⟩

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