The luminescence of Pr3+ ions doped in Y4Al2O9 by sol–gel synthesis

The Pr3+-doped Y4Al2O9 powders were synthesized by sol–gel method. Powder X-ray diffraction and SEM techniques were used to check for Y4Al2O9 powders. The Li+ co-doping with Pr3+ has an influence on the sintering temperature and morphology of the Y4Al2O9 powders produced from the gel. The emission spectra under different excitations, e.g., the 488 nm line of an argon-ion laser, X-ray and UV light, were investigated. The luminescence intensity of Y4Al2O9:Pr3+ could be increased with Li+ co-doping. Luminescence properties of Pr3+ ions in the two samples have some difference. In the Y4Al2O9:Pr3+, the emission at 490 nm from 3P0 is dominant, while, the Y4Al2O9:(Pr3+ + Li+) system was characterized by a red emission at 607 and 610 nm corresponding to the 1D2 → 3H4 inner transition of Pr3+ ions; and these two emissions show different excitation band from the 4f5d state.