Flow synthesized LiBaF3 nanocubes as a promising optically stimulated luminescence phosphor

Abstract

Integrating dosimeters are used in fields like personal dosimetry and radiotherapy quality assurance. Nanoparticles of LiBaF3 have been synthesized using a low-cost, high-throughput flow-synthesis setup and are found to be crystallographically phase-pure. Their radioluminescence (RL) emission shows three peaks corresponding to core-valence-band luminescence, self-trapped-exciton luminescence, and possibly impurity-related violet emission. Optically- and thermally stimulated luminescence (OSL and TL, respectively) overlap spectrally and show only the low-energy violet band, indicating a common luminescence pathway. The rapidly read-out OSL signal is linear in dose up to ∼1 kGy. The main TL glow peak, found around 120∘C, is depleted by optical stimulation, and similarly the OSL signal disappears following a TL readout. The thermal trap depth is found by the peak position method to be ∼1 eV. The high OSL light yield and reasonable fading of the nanoparticles qualifies them as an excellent candidate for OSL dosimetry.