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YVO_4:Er~(3+),Yb~(3+) with varying Yb~(3+) concentrations were prepared by a precipitation method.The results of X-ray diffraction (XRD) show that all the samples have a tetragonal zircon structure;the calculated average crystallite sizes are in the range of 14-22 nm.The lattice constants and cell volume of the samples decrease slightly with the increase in Yb~(3+) concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green emission is observed,which is attributed to the ~2H_(11/2)→4I_(15/2) and ~4S_(3/2)→~4I_(15/2) transitions of Er~(3+),and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Yb~(3+)concentration.These results reveal that the upconversion processes of YVO_4:Er~(3+),Yb~(3+) are related to the structure and the doping Yb~(3+) concentration of the sample.
YVO_4: Er ~ (3 +), Yb ~ (3+) with varying Yb ~ (3+) concentrations were prepared by a precipitation method. The results of X-ray diffraction (XRD) show that all the samples have a tetragonal zircon the calculated average crystallite sizes are in the range of 14-22 nm. The lattice constants and cell volume of the samples decrease slightly with the increase in Yb ~ (3+) concentration. The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation. The strong green emission is observed, which is attributed to ~ 2H_ (11/2) → 4I_ (15/2) and ~ 4S_ (3/2) → ~ 4I_ (15/2) transitions of Er ~ (3 +), and the red emission peaks in 650-675 nm can be ignored. The emission intensity for the sample depends on the Yb ~ (3+) concentration.These results reveal that the upconversion processes of YVO_4: Er ~ (3 +), Yb ~ (3+) are related to the structure and the doping Yb ~ (3 +) concentration of the sample.