Preparation and upconversion luminescence of YVO4:Er3+,Yb3+

YVO:Er,Ybwith varying Ybconcentrations 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 Ybconcentration.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→4Iand ~4S→~4Itransitions of Er,and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Ybconcentration.These results reveal that the upconversion processes of YVO:Er,Ybare related to the structure and the doping Ybconcentration of the sample.