In situ co-precipitation synthesis and photoluminescence of Y_xGd_(1-x)VO_4: Tm~(3+) microcrystalline phosphors by hybrid precursors

摘要

Y_xGd_(1-x)VO_4: Tm~(3+) (5 mol%) phosphors were prepared by in situ co-precipitation technology with the different content ratio of Y/Gd (x = 0.2,0.3,0.4,0.5,0.6,0.8, respectively). During the process, rare earth coordination polymers with o-hydroxylbenzoate were used as precursors, composing with polyethylene glycol (PEG) as dispersing media. After heat-treatment of the resulting multicomponent hybrid precursors at 900 ℃, the samples were obtained. SEM indicated the particles present good crystalline state, whose crystalline grain sizes were about 0.2-2 μm. Under the excitation of 257 nm, all the materials show the characteristic emission of Tm~(3+) which is the strong blue emission centered at 475 nm originating from ~1G_4 → ~3H_6 of Tm~(3+). Besides this, concentration quenching appears in the system of YVO_4: Tm~(3+) and GdVO_4: Tm~(3+). And when x reaches 0.5, the system of Y_xGd_(1-x)VO_4: Tm~(3+) shows the strongest blue emission.