Flux-aided synthesis of Lu2O3 and Lu2O3: Eu-single crystal structure, morphology control and radioluminescence efficiency

Abstract

Li2SO4 or (Li2SO4 + SiO2)-mixture fluxes were used to prepare a Lu2O3:Eu powder phosphor as well as an undoped Lu2O3 utilizing commercial lutetia and europia as starting reagents. SEM images showed that the fabricated powders were non-agglomerated and the particles sizes varied from single microns to tens of micrometers depending largely on the flux composition rather than the oxide(s)-to-flux ratio. In the presence of SiO2 in the flux, certain grains grew up to 300-400 μm. The lack of agglomeration and the large sizes of crystallites allowed making single crystal structural measurements and analysis on an undoped Lu2O3 obtained by means of the flux technique. The cubic structure with a = 10.393(2) Å, and Ia3 space group at 298 K was determined. The most efficient radioluminescence of Lu2O3:Eu powders reached 95%-105% of the commercial Gd2O2S:Eu.