Er-doped phosphate glass ceramics were fabricated by melt-quenching technique followed by a heat treatment. The effect of the crystallization on the structural and luminescence properties of phosphate glasses containing Al₂O₃, TiO₂, and ZnO was investigated. The morphological and structural properties of the glass ceramics were characterized by Field Emission-Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), and micro-Raman spectroscopy. Additionally, the luminescence spectra and the lifetime values were measured in order to study the influence of the crystallization on the spectroscopic properties of the glasses. The volume ratio between the crystal and the glassy phases increased along with the duration of the heat treatment. The crystallization of the glass ceramics was confirmed by the presence of sharp peaks in the XRD patterns and different crystal phases were identified depending on the glass composition. Sr(PO₃)₂ crystals were found to precipitate in all the investigated glasses. As evidenced by the spectroscopic properties, the site of the Er³⁺ ions was not strongly affected by the heat treatment except for the fully crystallized glass ceramic which does not contain Al₂O₃, TiO₂, and ZnO. An increase of the lifetime was also observed after the heat treatment of this glass. Therefore, we suspect that the Er³⁺ ions are incorporated in the precipitated crystals only in this glass ceramic.

The effect of the incorporation of Er₂O₃-doped particles on the structural and luminescence properties of phosphate glasses was investigated. A series of different Er₂O₃-doped TiO₂, ZnO, and ZrO₂ microparticles was synthesized using soft chemistry and then added into various phosphate glasses after the melting at a lower temperature than the melting temperature. The compositional, morphological, and structural analyses of the particles-containing glasses were performed using elemental mapping by field emission-scanning electron microscopy (FE-SEM) with energy dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD). Additionally, the luminescence spectra and the lifetime values were measured to study the influence of the particles incorporation on the spectroscopic properties of the glasses. From the spectroscopic properties of the glasses with the composition 50P₂O₅-40SrO-10Na₂O, a large amount of the Er₂O₃-doped particles is thought to dissolve during the glass melting. Conversely, the particles were found to survive in glasses with a composition 90NaPO₃-(10 − x)Na₂O-xNaF (with x = 0 and 10 mol %) due to their lower processing temperature, thus clearly showing that the direct doping method is a promising technique for the development of new active glasses.

Titania particles doped with various concentrations of Erbium were synthesized by the sol-gel method followed by different heat treatments. The shape and the grain growth of the particles were noticeably affected by the concentration of Erbium and the heat treatment conditions. An infrared emission at 1530 nm, as well as green and red up-conversion emissions at 550 and 670 nm, were observed under excitation at 976 nm from all of the synthesized particles. The emission spectra and lifetime values appeared to be strongly influenced by the presence of the different crystalline phases. This work presents important guidelines for the synthesis of functional Er³⁺-doped titania particles with controlled and tailored spectroscopic properties for photonic applications.