Synthesis And Characteristiztion Of YAG: Ce Nanoparticles And Bulk Materials

Cerium-doped yttrium aluminum garnet (Chemical formula is Y3Al5O12: Ce³⁺, abbreviated as YAG: Ce³⁺ or YAG: Ce) phosphors were prepared by co-precipitation, combustion, sol-gel and fiter-template method. X-ray diffraction, fourier transform infrared spectroscopy, differential scanning calorimetry/thermal gravimetric, transmission electron microscope, scanning electron microscope and photoluminescence spectrum were used to characterize the products.The concentration of Al³⁺ ions in the metal nitrates solution is 0.1 mol/l and the concentration of NH4HCO3 solution is 0.5 mol/l were defined as the optimum condition for co-precipitation method. In this condition, phase-pure YAG: Ce phosphors were obtained at 1000℃, and the phosphors'particles are nearly spherical shape and well dispersed, and the average particles size is about 20-30 nm; when C16H33(CH3)3NBr (CTAB) was used for dispersant in the co-precipitation process, phase-pure YAG: Ce phosphors were obtained at 900℃. The molar ratio of Y³⁺ ions to urea is 1:9 was regarded as the optimum condition for the combustion reaction. In this condition, the mixed solution of nitrates and urea was ignited at 300-700℃. The results show that when the ignition temperature is 600℃, the crystalline phase of the sample is phase-pure YAG; The samples which were prepared at different ignition temperature were repeated calcined at 1000℃in N2 atmosphere, and the results show that all repeated calcined powders were phase-pure YAG, and the PL intensity of the samples was enhanced a lot. Phase-pure YAG: Ce phosphors were synthesized at 900℃by stearic acid sol-gel method. When the ratio of nitrates to C17H35COOH is 2:1, spherical nanoparticles and acicular structure particles coexisted in the YAG: Ce phosphors; When the ratio of nitrates to C17H35COOH is 1:3, the shape of the synthesized YAG: Ce phosphors is layered structure with irregular structure. Using qualitative filter paper as template, YAG: Ce phosphors were prepared by three different production processes at 1100℃; each sample has unique morphology and larger size.PL spectrum show that all the YAG: Ce phosphors prepared via different methods can be well excited by blue light whose wavelength is about 465 nm, and the emitted light is yellow-green light whose wavelength is about 530 nm. The PL intensity of the phosphors prepared by co-precipitation and fiter-template method were lower, and the PL intensity of the phosphors prepared by sol-gel and combustion method were higher.