Synthesis and up-conversion luminescence properties of Er3+/Yb3+ co-doped Sr2CeO4 phosphors

Abstract Er 3+ /Yb 3+ co-doped Sr 2 CeO 4 phosphors were synthesized using a high-energy ball milling method at 1100 °C. The X-ray diffraction patterns confirmed their orthorhombic structure. The up-conversion emissions corresponding to 2 H 11/2 → 4 I 15/2, S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions peaking at 526 nm, 552 nm and 669 nm have been observed under 975 nm excitation. With the help of a schematic energy level diagram the up-conversion mechanisms were discussed in detail. The excited state absorption and energy transfer process were discussed as possible up-conversion mechanisms. The energy back transfer ( 4 S 3/2 + 2 F 7/2 → 4 I 13/2 + 2 F 5/2 ) contribute the increased intensity ratio of red to green emission in Sr 2 CeO 4 :Er 3+ /Yb 3+ samples. A decay curve analysis for the UC emission corresponding to the 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions in the Er 3+ /Yb 3+ co-doped Sr 2 CeO 4 phosphors was performed. The CIE chromaticity coordinates of the Er 3+ /Yb 3+ co-doped Sr 2 CeO 4 phosphors were located in the green region. The results indicate that the material may be suitable for applications in the fields of color displays and light emitting devices.