Luminescence of KLuP2O7 Powder Doped with Pr3+ Ions upon Different Types of Excitation

This paper reports the spectroscopic properties of praseodymium-doped potassium lutetium double phosphates, KLuP₂O₇:Pr3+ (1%). Spectra of photoluminescence, photoluminescence excitation, X-ray excited luminescence and pulse cathodoluminescence, thermally stimulated luminescence were investigated. KLuP₂O₇:Pr3+ showed Pr3+ emission connected both with high intensity interconfigurational $4f^{1}5d^{1} \rightarrow 4f^{2}$ transitions (UV bands in region of 250–320 nm), intraconfigurational $4f^{2} \rightarrow 4f^{2}$ transitions (weak lines in vision spectral region) and Stocks defect-related luminescence. Upon both UV intra-center and band-to-band excitation with ionizing radiation, emission spectra of KLuP₂O₇:Pr3+ are dominated by Pr3+ interconfigurational $4f^{1}5d^{1} \rightarrow 4f^{2}$ radiative transitions. Luminescence decay kinetics measurements established decay time $\tau \approx 19$ ns at room temperature. The study of thermally stimulated luminescence demonstrates effective light storage. Parameters of charge carriers' traps were calculated: $\Delta E_{1} = 1.1$ eV (for peak at 352 K) and $\Delta E_{2} = 1.3$ eV (for peak at 388 K).