Photo-stimulated luminescence from europium-doped rubidium barium bromide in fluorozirconate glass ceramics

Photoluminescence and photo-stimulated luminescence (PSL) measurements on rubidium- and europium-doped fluorobromozirconate glass ceramics are reported. The particle sizes and the volume fractions of the Rb2BaBr4 and RbBa2Br5 crystalline phases which form following annealing have been measured by X-ray diffraction, and the evolution of crystallisation has been monitored through the photoluminescence of Eu2+ ions in these crystals. The Rb2BaBr4 phase shows no PSL, but the RbBa2Br5 phase shows PSL involving the Eu2+ ions, with an efficiency of up to 8% of that found for the commercial X-ray storage phosphor BaFBr:Eu2+. The RbBa2Br5 crystallite size must be greater than 70 nm for efficient PSL.