Reproducible Solvent-Thermal Synthesis, Controlled Microstructure,and Photoluminescence of REPO_4:Eu~(3+), Tb~(3+) (RE = Y, La, and Gd) Nanophosphors

摘要

By altering the temperature and solvents, we have synthesized hydrated and dehydrated Eu~(3+)/Tb~(3+)-doped REPO_4 (RE = Y, La, and Gd) nanophosphors via a solvo-thermal technology. X-ray powder diffraction and scanning electronic microscopy reveal that they have different structures and different morphologies. REPO4 prepared under subsequent heating at 80°, 120°, and 160℃ for 1 day, respectively, present larger particle size than that formed by heating at 160℃ for 3 days. Moreover, at the same temperature of 160 ℃ and pH 3, three different solvents (ethanol, N,N-dimethyrformamide (DMF), and water) were used, whose influence on the microstructure of LaPO_4 has been examined. As a result, LaPO_4 samples from anhydrous ethanol solvent show a pure hexagonal phase and nanowire morphology, just like that prepared from the water solvent. On the other hand, the microstructure of LaPO_4 samples from DMF-H_2O-mixed solvents have been changed: with the increasing volume ratio of DMF to H_2O, the crystal phase of LaPO_4 has been changed from hexagonal phase to monoclinic phase and the morphology from nanowires to nanoparticles. Finally, the photoluminescence properties of these Eu~(3+) (Tb~(3+))-activated rare earth phosphates have been investigated, indicating that the photoluminescent behavior are related to their crystal phases and microstructures.