Luminescence and defect studies of Ce3+ doped CaS phosphor synthesized via solid state diffusion method

Cerium dope CaS phosphor has been successfully prepared by solid state diffusion method. The phosphor is characterized by X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, thermogravimetric analysis and photoluminescence. Thermoluminescence and electron spin resonance studies also have been carried out on CaS:Ce phosphor. Irradiated CaS:Ce exhibits electron spin resonance (ESR) lines due to defect centres. The thermal annealing behaviour of one of the defect centres appears to correlate with the thermoluminescence (TL) peak at 135 °C. The centre is characterized by an isotropic g-value of 2.0036 and is assigned to a F+ centre.