Luminescent properties of Eu2+, Eu3+ and Dy3+ co-activated SrAl2O4 nanocrystals

By the control of the reducing atmospheres in the one-pot combustion reactions, Eu2+, Eu3+ and Dy3+ co-activated strontium aluminate oxide were synthesized. X-ray diffraction confirmed the formation of monoclinic SrAl2O4 nanocrystals. The photoluminescence spectra of the phosphors were measured. It is found that three sharp emissions at 483, 570 and 615 nm were superimposed onto the broad green emission band at about 520 urn. The origins of the broad green luminescent band, the sharp blue at 483 nm, and sharp yellow emissions at 570 nm and the sharp red emissions at 615 nm can be attributed to the 4f(6)5d(1)--> 4f(7) transitions of Eu2+ ions, the F-4(9/2)-> H-6(15/2) transition of Dy3+ ions, the F-4(9/2)-> H-6(13/2) transition of Dy3+ ions, and the D-5(0)-F-7(2) transition of Eu3+ ions in the SrAl2O4 nanocrystals, respectively. The results indicate that the white light emitting phosphors are possible by tuning the relative molar percentages of Eu2+, Eu3+ and Dy3+ in the phosphors.