Photoluminescence and phosphorescence properties of MAl2O4:Eu2+, Dy3+ (M=Ca, Ba, Sr) phosphors prepared at an initiating combustion temperature of 500°C

Eu2+ and Dy3+ co-doped calcium aluminate, barium aluminate and strontium aluminate phosphors were synthesized at an initiating combustion temperature of 500 degrees C using urea as an organic fuel. The crystallinity of the phosphors was investigated by using X-ray diffraction (XRD) and the morphology was determined by a scanning electron microscope (SEM). The low temperature monochnic structure for both CaAl2O4 and SrAl2O4 and the hexagonal structure of BaAl2O4 were observed. The effect of the host materials on the photoluminescence (PL) and phosphorescence properties were investigated by using a He-Cd Laser and a Cary Eclipse fluorescence spectro photometer, respectively. The broad band emission spectra observed at 449 nm for CaAl2O4:Eu2+, Dy3+, 450 nm (with a shoulder-peak at 500 nm) for BaAl2O4:Eu2+, Dy3+ and 528 nm for SrAl2O4:Eu2+, Dy3+ are attributed to the 4f(6)5d(1) to 4f(7) transition in the Eu2+ ion in the different hosts. (C) 2009 Elsevier B.V. All rights reserved.