This work focuses on the preparation and characterization of sulfides and oxysulfide materials for passive or active optical applications. Precipitation and combustion synthesis were used as synthesis methods for the preparation of the precursor nanopowders such as ZnS, CaLa₂S₄, BaLa₂S₄ or La₂O₂S. Additional treatment under H₂S/N₂ was performed to purify the powders without modifying the cubic structure (ZnS) which is necessary for obtaining transparent ceramics. ZnS ceramics, with a maximum transmission of about 70% at the wavelength of 10 µm, were elaborated by Hot Pressing or Spark Plasma Sintering techniques for optical applications in the 8-12 µm. Fe²⁺ doped ZnS powders were synthesized and studied with a large emission band between 3 µm and 4.5 µm. Lasing has been obtained between 3.4 µm and 3.6 µm depending on the temperature. Er³⁺ and Yb³⁺ co-doped lanthanum oxysulfide powders were studied as fluorescent materials for solar spectrum in order to increase the efficiency of photovoltaic solar cells. Quantum yield higher than 100% was obtained with pumping at 523 nm for emission in the visible and the near-infrared. These results show that the lanthanum oxysulfide materials are efficient hosts for rare earths doping.
