Controlled Synthesis and Optical Properties of Lanthanide-doped Na3ZrF7 Nanocrystals

In this paper,we report for the first time the controlled synthesis of lanthanide ion(Ln3+)-doped tetragonal-phase Na3Zr F7nanocrystals(NCs)via a high-temperature co-precipitation approach.The as-synthesized Na3Zr F7NCs are systematically studied by utilizing the XRD,TEM as well as high-resolution photoluminescence(PL)spectroscopy.The morphology and size for the as-synthesized Na3Zr F7NCs can be finely controlled by changing the experimental parameters such as the amount of precursor,solvent ratio,reaction temperature and time.By utilizing the red-emitting Eu3+ion as an efficient optical/structural probe,the successful hetero-valence doping of Ln3+activators in the lattices of Na3Zr F7NCs is well-established regardless of their different valences and radii between host Zr4+ion and Ln3+dopant.As a result,intense upconversion(UC)luminescence(UCL)ranging from UV to visible and to NIR spectral regions can be readily achieved after the doping of typical UCL couples of Yb3+/Er3+,Yb3+/Tm3+and Yb3+/Ho3+into the lattices of Na3Zr F7NCs when excited by using a 980-nm NIR diode laser.