Tuned structure of europium-doped Al2O3-ytrium luminescent composites and their spectroscopic behavior

Abstract

This work proposes a smart way to produce lanthanide-doped alumina and yttrium spherical compounds. We were able to tune the structure of the Al2O3-yttrium binary material prepared herein by controlling the Y3+/Al3+ ratio. Small ratio (Y0·1/Al1 mol/mol) afforded the metastable hexagonal phase (YAlO3), which remained stable in the final product even after thermal treatment at 1100 °C. On the basis of XRD data, increasing Y3+/Al3+ ratio led to the formation of the crystalline YAG phase after thermal treatment. The luminescence data showed that Eu3+ ions doped into the binary material were highly sensitive to changes in the environment around the Eu3+ ion, and the emission spectra corroborated that the latter ion migrated to yttrium sites in the YAG structure. The luminescence confirmed the presence of a secondary Eu3+ ion coordination site in the material, but at higher Y3+/Al3+ ratio, the YAG structure has predominated.