Luminescence of ZnGa2Î4 AND ZnAl2Î4 spinels doped with Eu3+AND Tb3+ ions

Abstract

Spinel type mono-phase the ZnGa2O4 and ZnAl2O4 compounds doped with Eu3+ and Tb3+ ions were obtained using two methods: solid phase reactions and deposition from chemical solutions. The luminescent analysis of the materials shows that the rare earth ions are localised at the defect sites (regions) of the crystallite (grain) boundaries. The emission spectra of the samples with europium are characterized by an intense emission in red region due to the 5D0 → 7F1,2 transitions of Eu3+ ions, whereas, in the case of terbium, the highest intensity corresponds to the green emission due to the 5D4 → 7F5 transitions of Tb3+ ions. The intensities of the intra-shell emission of the Eu3+ and Tb3+ ions in comparison with luminescence intensity of the chromium impurity traces (residual small amount of the Cr3+ ions) show that the materials doped with transition metals are more promising for development of phosphors based on oxide spinels than the materials doped with rare-earth elements.