Molten Salt Synthesis and Luminescent Properties of GdVO4:Eu3+ Nanophosphors

GdVO 4 :Eu 3+ nanophosphors were prepared via molten salt synthesis. Equal moles of NaNO 3 and KNO 3 were used as reaction medium, rare earth nitrates and NH 4 VO 3 as precursors, and NaOH as alkalizer. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), photoluminescence (PL) spectrum and lifetime were used to characterize the nanophosphors. XRD demonstrates that NaOH concentration and the sintering temperature play important roles in the crystallinity and the phase purity of the products. The optimum NaOH concentration and sintering temperature are 2:40 and 400 °C, respectively. TEM micrographs show that the GdVO 4 :Eu 3+ nanocrystals exhibit a cubic morphology and have a mean size of about 20 nm, which is in good agreement with that calculated by Scherrer's formula. Both the cell parameters and the volume of GdVO 4 :Eu 3+ nanocrystals decrease due to the existence of big quantity of dangling bonds on the particle surface. Upon excitation at 315 nm, the GdVO 4 :Eu 3+ nanocrystals show the strong characteristic emission of Eu 3+ , which indicates the efficient energy transfer from VO 4 3- groups to Eu 3+ . The best doping concentration of Eu 3+ in GdVO 4 is determined to be 5 mol%.