UV and VUV characteristics of (YGd)2O3:Eu phosphor particles prepared by spray pyrolysis from polymeric precursors

Red-emitting (YGd)(2)O-3:Eu phosphor particles, with high luminescence efficiency under vacuum ultraviolet (VUV) and ultraviolet (UV) excitation, were prepared by a large-scale spray pyrolysis process. To control the morphology of phosphor particles under severe preparation conditions, spray solution with polymeric precursors were introduced in spray pyrolysis. The prepared (YGd)(2)O-3:Eu phosphor particles had spherical shape and filled morphology even after post-treatment irrespective of Gd/Y ratio. In the case of solution with polymeric precursors, long polymeric chains formed by esterification reaction in a hot tubular reactor; the droplets turned into viscous gel, which retarded the precipitation of nitrate salts and promoted the volume precipitation of droplets. The brightness of (YGd)(2)O-3:Eu phosphor particles increased with increasing gadolinium content, and the Gd2O3:Eu phosphor had the highest luminescence intensity under UV and VUV excitation. The maximum peak intensity of Gd2O3:Eu phosphor particles under UV and VUV were 118 and 110% of the commercial Y2O3:Eu phosphor particles, respectively. (C) 2002 Elsevier Science Ltd. All rights reserved.