Effect of Mg2+ and TiIV doping on the luminescence of Y2O3:Eu3+

The Y2O3:Eu3+,Mg2+,TiIV materials (xEu: 0.02, xMg: 0.08, xTi: 0.04) were prepared by solid state reaction. The purity and crystal structure of the material was studied with the X-ray powder diffraction. Luminescence properties were studied in the UV-VUV range with the aid of synchrotron radiation. The emission of Y2O3:Eu3+,Mg2+,TiIV had a maximum at 612 nm (λexc: 250 nm) due to the 5D0→7F2 transition of Eu3+. The excitation spectra (λem: 612 nm) showed a broad band at 233 nm, due to the charge transfer transition between O2- and Eu3+, and at 297 nm due to the Ti→Eu3+ energy transfer. Only very weak persistent luminescence was discovered. In the room and 10 K temperature excitation spectra, the line at 208 nm is due to the formation of a free exciton (FE) and a broad band at 199 nm was related to the valence-to-conduction band absorption of the Y2O3 host lattice. The absorption edge was ca. 205 nm giving 6.1 eV as the energy gap of Y2O3.