Blue-emitting MWO4:Tm3+ (M: Sr, Ba) phosphors prepared by coprecipitation method at room temperature

Abstract

MWO4 host matrices (M: Sr, Ba) doped with different Tm3+ concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 mol%) have been successfully prepared by the coprecipitation method at room temperature. The as-prepared nanophosphors were characterized by infrared spectroscopy showing intense absorption bands in the range of 700-1000 cm-1 attributed to the symmetrical and asymmetrical stretching vibrations (ν) of the tetrahedral [WO4]2- group. The X-ray diffraction (XRD) measurements reveal the tetragonal scheelite phase with the I41/a (No. 88) space group. The emission spectra of the MWO4:Tm3+ materials are dominated by the highest intensity narrow band of the intraconfigurational 1D2 → 3F4 transitions in the blue region (ca. 456 nm) arising from the Tm3+ ions. Additional low-intensity emission bands originated from the 1G4 → 3H6 (ca. 475 nm), 1G4 → 3F4 (660 nm) and 3H4 → 3H6 (700 nm) transitions are also observed. These optical results indicate that the materials can be used as an alternative to blue-emitting markers.