Sintetizzazione e caratterizzazione di ceramiche trasparenti e fosfori a base di ossisolfuro

Lanthanum oxysulfide (La2O2S) compounds possess unique combination of physicochemical properties (high thermal and chemical stability, large domain of transparency, low phonon energy…) that make these materials ideal candidates for both active and passive optical applications. In one hand, La2O2S exhibits a transparency window up to infrared region allowing various applications such as thermal cameras or missiles guiding systems. In the other hand, when doped with rare earth trivalent ions, La2O2S behaves as a phosphor enabling energy conversion phenomena and other luminescence properties. This study, investigating the passive and active optics properties of the processed ceramics, is the direct continuation of a previous master thesis performed by Louis Cornet in the V&C team at ISCR, Université de Rennes 1. The La2O2S powders are prepared using a combustion method followed by a sulfurization treatment. Ceramics are obtained by hotpressing the synthesized powders at different sintering temperatures. Materials are characterized by X-ray Diffraction, UV/Vis/IR spectroscopy, laser granulometry, Scanning Electron Microscopy and specific surface area measurements. This manuscript is constituted of three chapters. The first chapter relates to theoretical concepts on active and passive optics. The second chapter is a description of the experimental procedure and experimental techniques involved. And the third chapter presents the results of the synthesis and characterization of the La2O2S powders and their processing as ceramics. Unfortunately, no experiments have been yet performed on doped materials due to a lack of time induced by the corona virus situation.