Intense Red Fluorescence From Surface Traps in BaSO4:V5+, Eu3+ and Its Applications

ABSTRACT BaSO 4 :V 5+ synthesized at 1000°C in air exhibits an intense emission band peaking at 495 nm from surface traps assisted by atmospheric oxygen on excitation at 350 nm due to charge transfer from O 2− to V 5+ in the (VO 4 ) 3− tetrahedral complex. BaSO 4 :Eu synthesized under similar conditions exhibits both Eu 2+ (375 nm) and Eu 3+ (619 nm) fluorescence. Vanadium codoping quenches the Eu 2+ fluorescence but enhances the Eu 3+ fluorescence in BaSO 4 :V, Eu due to charge compensation. However, Eu codoping quenches the vanadium fluorescence by diffusion of vanadium into the crystal, and V 2 O 5 also serves as a flux enhancing Eu 3+ doping efficiency in BaSO 4 lattice. The 619nm Eu 3+ PL emission intensity in BaSO 4 :V 5+ , Eu 3+ is comparable to 592nm emission from commercial (Y,Gd) BO 3 :Eu 3+ . However, V 5+ emission shows strong thermal quenching, while Eu 3+ emission shows little thermal quenching up to 210°C, making BaSO 4 :V 5+ , Eu 3+ a promising new red phosphor for improving the color rendering of blue light‐based white LED. The ratio of Eu 3+ to V 5+ fluorescence increases with excitation temperature (30°C°C–180°C) enabling BaSO 4 :V 5+ , Eu 3+ to be used as a non‐contact luminescence thermometer.