Synthesis, characterization and photoluminescent property of barium tungstate and holmium-doped barium tungstate

Barium tungstate (BaWO₄) is an important ceramic material belonging to the family of scheelites, which is applied as photoluminescent material, as scintillator, light-emitting diodes (LEDs), solid-state lasers, among other, being a host matrix for lanthanide ions, due to its chemical and mechanical stability. This research aims to synthetize, characterize structurally and evaluate photoluminescent properties of barium tungstate powders and Ho³⁺-doped barium tungstate. Powders of Ba_1-xHo_2x/3WO₄ (x= 0, 0.01 and 0.02) were obtained by coprecipitation and characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier-Transformed Infrared spectroscopy (FTIR), UV-Vis spectroscopy, scanning electron microscopy (SEM) and photoluminescent spectroscopy. XRD and Raman spectroscopy analyses revealed crystalline ordering for these materials. Their morphology was characterized by the presence of octahedral grains with heterogeneous distribution of grain size. A broad band centered at 475 nm was identified for BaWO₄ at 350,7 nm excitation in emission spectrum. The addiction of holmium ions into the BaWO₄ matrix promoted a significant reduction of the optical gap and characteristic transitions (f-f transitions) of ions Ho³⁺were identified.

barium tungstate; photoluminescence; holmium