Luminescent characteristics and microstructures of Sr2CeO4 phosphors prepared via sol-gel and solid-state reaction routes

Blue-light-emitting Sr2CeO4 phosphors were synthesized via a sol-gel process and the conventional solid-state method in this study. The developed sol-gel process lowered the synthesis temperature of monophasic Sr2CeO4 to as low as 900 degrees C. In comparison with the solid-state derived powders, the sol-gel derived powders had more uniform morphology and smaller particle sizes. In addition, sol-gel derived Sr2CeO4 displayed higher luminescent intensity than that prepared via the solid-state route under the same heating conditions. This is attributed to the improved compositional homogeneity and crystallinity in the sol-gel process. During the heating processes, Sr2CeO4 tended to thermally decompose at elevated temperatures. This decomposition reaction resulted in the formation of an impurity phase- SrCeO3 and thereby a decrease in the luminescent intensity. For obtaining Sr2CeO4 phosphors with high luminescent intensity, the heating conditions in both processes need to be well modulated.