Controlled synthesis and tunable luminescence of NaYF4:Eu3+

High quality NaYF4:Eu3+ luminescent materials were successfully synthesized via a facile template technique by hydrothermal method. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and fluorescence spectroscopy (FS). The incorporating of Eu3+ ions into NaYF4 crystal lattice influenced the symmetry types of NaYF4 crystals, resulting in phase transformation of NaYF4 crystals between α and β phase. The pure hexagonal phase of branched NaYF4: Eu3+ was obtained as the Eu3+ concentration reached 15 mol.%. In addition, the luminescence color was tuned by changing the doping concentration of Eu3+ ions.