LiAlO2:Mn/Ce/Tb phosphors were prepared by combustion synthesis. LiAlO2:Mn exhibits 2 thermally-stimulated luminescence peaked around 150 and 320C, while LiAlO2:Ce/Tb exhibits thermally-stimulated luminescence peaks around 170 and 280C. Photoluminescence emission of LiAlO2:Mn consists of a peak around 500nm when excited with 450nm, while LiAlO2:Ce shows a broad band around 400nm when excited by 320nm. The thermally-stimulated luminescence emission spectra of LiAlO2:Mn/Tb indicate that Mn2+/Tb3+ was the luminescence centre. LiAlO2:Ce and LiAlO2:Tb exhibited optically stimulated luminescence when stimulated with 470nm light. Electron spin resonance studies were carried out to identify defect centres responsible for thermally-stimulated luminescence peaks observed in LiAlO2:Ce. Room temperature electron spin resonance spectra of irradiated LiAlO2 : Ce/Tb phosphor appear to be in a superposition of at least 4 distinct centres. Two defect centres (centre I and centre II) were identified in irradiated LiAlO2:Ce/Tb phosphor and these centres were attributed to O- and F+ centres, respectively. O- centre appears to correlate with the 170C thermally-stimulated luminescence peak and F+ centre appears to correlate with both 170 and 280C thermally-stimulated luminescence peaks in LiAlO2:Ce.

Identification of Defect Centres using TSL, PL, OSL and ESR Studies in LiAlO2 Based Phosphors. B.Dhabekar, E.A.Raja, S.Menon, T.K.G.Rao, R.K.Kher, B.C.Bhatt: Journal of Physics D, 2008, 41[11], 115414 (6pp)