Luminescence properties of terbium-doped Li3PO4 phosphor for radiation dosimetry

A polycrystalline sample of Li3PO4:Tb3+ phosphor was successfully synthesized using solid-state diffusion method. This synthesis method is of low cost, low temperature and does not require any other atmospheres for the synthesis. The powder X-ray diffraction (PXRD), photoluminescence (PL) emission and excitation spectra, thermoluminescence (TL) and optically stimulated luminescence (OSL) were measured. The particle size was calculated using the Debye Scherrer formula and found to be 79.42 nm. PL emission spectra of Li3PO4:Tb3+ phosphor show the strong prominent peak at 544 nm corresponding to 5D4 to 7F5 transitions of Tb3+. The OSL sensitivity of prepared Li3PO4:Tb3+ phosphor was 50% of that of α-Al2O3:C. Its decay curve consists of three components with photoionization cross-sections 0.44 × 10−17, 3.09 × 10−17 and 23×10−17 cm2. The TL glow curve of the prepared sample consists of two characteristic peaks, which were deconvoluted using the peak fit software, and kinetic parameters were determined using the peak shape method. TL intensity was compared with that of the commercially available TLD-500 phosphor. OSL dose response was linear in the measured range and the minimum detectable dose (MDD) was found to be 67.42 μGy, while fading of the OSL signal was found to be about 27% in 4200 min after which the OSL signal stabilizes.