Synthesis, photoluminescence, thermoluminescence and electron spin resonance investigations of CaAl12O19:Eu phosphor

The present paper describes the synthesis of europium-doped calcium aluminate phosphor using the combustion method. An efficient blue emission phosphor can be prepared at reaction temperatures as low as 500 degrees C in a few minutes by this method. Characterization of the powder was done by X-ray diffraction, transmission electron microscopy, scanning electron microscope analysis and the optical properties were studied by photoluminescence spectra. Thermoluminescence (TL) studies also have been carried out on CaAl12O19:Eu2+ phosphor. The TL glow curve shows peaks at 174 and 240 degrees C. Defect centres formed in irradiated phosphor have been studied using the technique of electron spin resonance. Step annealing measurements, indicate that one of the annealing stages of a defect centre appear to correlate with the release of carriers resulting in TL peak at 174 degrees C. The centre is characterized by an isotropic g-value of 2.0046 and is assigned to a F+ centre. (C) 2006 Elsevier B.V. All rights reserved.