Characterization, photoluminescence and correlation between thermoluminescence and ESR of combustion synthesized CaAl2O4:Sm3+ material

Abstract Samarium-doped monoclinic CaAl 2 O 4 phosphor was prepared at furnace temperatures as low as 500 °C in a short time of 5 min by using the combustion route. Powder X-ray diffraction and scanning electron microscopy studies were used to characterize the prepared combustion powder. Photoluminescence spectra revealed that samarium ions are present in trivalent oxidation states. The CaAl 2 O 4 :Sm exhibits two thermoluminescence glow curves at around 135 and 325 °C. The defect centres formed in the phosphor are studied using the technique of electron spin resonance (ESR). Irradiated CaAl 2 O 4 :Sm shows ESR lines due to a radiation induced Fe 3 + ion and a defect centre. The defect centre is characterized by an isotropic g -value 2.0036 and is assigned to an F + centre. The radiation induced Fe 3 + ion appears to correlate with the main TSL peak at 325 °C.