Understanding the reversible reduction of Eu3+ in calcium molybdate phosphors: combined in situ XAS-XRD investigation during high temperatur

The aim of the project is to investigate the local structural evolution of photoluminescent inorganic materials, i.e. Eu3+-doped calcium molybdate (CaMoO4), during high temperature annealing. We are focused on unravelling to which extent different synthetic approaches, i.e. inverse miniemulsion (wet-chemistry) and ball milling (solid state-chemistry), affect the local structure of inorganic materials in particular during the annealing. We aim to evaluate the dopant-induced variations on the structure (electronic, short- and long-range) through a combination of X-ray absorption spectroscopy (at Eu L3-edge and Mo K-edge) and X-ray diffraction in situ measurements while annealing at 900 °C, both in He and in air. With these findings we aim to thoroughly understand the reversible structural and electronic changes occurring during the annealing process, which are found to strongly affect the photoluminescent (Eu2+-Eu3+) properties, to a different extent depending on the synthetic route.