A rapid combustion process for the preparation of MgSrAl 10O 17:Eu 2+ phosphor and related luminescence and defect investigations

Abstract

Blue-emitting europium-ion-doped MgSrAl 10O 17 phosphor, prepared using the combustion method, is described. An efficient phosphor can be prepared by this method in a muffle furnace maintained at 500 °C in a very short time of few minutes. The phosphor is characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and BET surface area measurements. Photoluminescence (PL) spectra revealed that europium ions were present in divalent oxidation state. The thermoluminescence (TL) glow curve shows two peaks at around 178 and at 354 °C. The defect centres formed in the phosphor are studied using electron spin resonance (ESR). The ESR spectrum indicates the presence of Fe 3+ ions in the non-irradiated system. Irradiated MgSrAl 10O 17:Eu exhibits lines due to radiation-sensitive Fe 3+ ion and a defect centre. The centre is characterized by an isotropic g-value of 2.0012 and is assigned to a F + centre. The radiation-sensitive Fe 3+ ion appears to correlate with the main TL peak at 178 °C. During irradiation an electron is released from Fe 2+ and is trapped at an anion vacancy to form F + centre. During heating, an electron is liberated from the defect centre and recombines with Fe 3+ emitting light.