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 °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 °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 °C. The centre is characterized by an isotropic g-value of 2.0046 and is assigned to a F+ centre.