Photoluminescence, thermo- and optically stimulated luminescence properties of Eu3+ doped Sr2P2O7 synthesized by the solvent evaporation method

In this research, undoped and Eu3+ (0.5, 1, 3, 5, 8 and 10 mol%) doped strontium pyrophosphate (Sr2P2O7) powders were synthesized by the solvent evaporation method and their luminescence properties were studied by photoluminescence (PL), thermoluminescence (TL) and, for the first time, optically stimulated luminescence in continuous wave modality (CW-OSL). The Sr2P2O7:Eu3+ material was structural and morphological characterized using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The PL excitation and emission spectra exhibited transitions related to Eu3+ ions into the Sr2P2O7 host lattice. In the excitation spectrum an intense broad charge transfer band around 267 nm was observed in all doped samples. A chemical reduction process of the Eu3+ ions incorporated in the Sr2P2O7 host is carried out when the samples are exposed to 90Sr beta particles and it is a crucial factor in the TL and CW-OSL responses. The TL response of the Eu3+ doped Sr2P2O7 samples, displays light emissions associated with the presence of Eu3+ and Eu2+ ions. The undoped Sr2P2O7 showed TL maxima at 95, 150 and 230 °C and CW-OSL fast decay when the samples are stimulated with infrared light. All Sr2P2O7 and Sr2P2O7:Eu3+ (0.5 and 1 mol%) samples showed TL and CW-OSL linear response in the range of 0.5-25 Gy and acceptable repeatability with a variation coefficient lower than 5%. Using CW-OSL and TL dose-response the minimum detectable dose was estimated as 2 mGy (TL-0.5 mol%), 3 mGy (TL-1 mol%), 14 mGy (TL-undoped) and 2 mGy (CW-OSL-undoped).