On the cathodoluminescence and thermoluminescence emission of lithium titanate ceramics

We herein report on the radiation effects of Li2TiO3 ceramics sintered at 1150 and 1350 °C by means of its UV-IR cathodoluminescence (CL) and thermoluminescence (TL) properties. The CL spectral emission decreases in ceramic samples with the higher sintering temperature, which could be associated with subtle changes in the lattice structure (the beta-to-gamma transformation as illustrated in a XRD analysis). The study of the TL response to gamma-ray dose (17, 168 and 1400 kGy) and the fading effect (up to 2184 h of storage time) of these samples indicates that the UV-blue glow emission (i) exhibits a saturating exponential behaviour with dose, regardless the elapsed time from the irradiation process; (ii) displays an initial rapid decay (ca. 20%) with storage time, maintaining the stability from 30 to 40 days onwards after 3 months of storage following a first-order decay behaviour and (iii) seems to confirm a continuum in the trap distribution, after applying tests of thermal stability at different temperatures. Additionally, successive irradiation-heating cycles give rise to a progressive increase in the TL intensity due to an increase of holes concentration in luminescence centres.