Energy transfer processes in LuAG:Ce and LuAG:Ce, Pr single crystalline film scintillators

This work is devoted to examining the influence of energy transfer processes between Ce³⁺ and Pr³⁺ ions on the luminescent and scintillation properties of LuAG:Ce and LuAG:Ce,Pr scintillators, grown by liquid phase epitaxy onto undoped LuAG substrates with a PbO–B₂O₃-based flux. To characterize them, measurements of the absorption, cathodoluminescence, photoluminescence emission and excitation spectra as well as the photoluminescence decay kinetics of the SCFs under study were performed. The investigation confirmed simultaneous energy transfer processes between d-f and f-f states of Pr³⁺ ions and between Pr³⁺ (d-f) and Ce³⁺ (d-f) ions, as well as from Ce³⁺ (d-f) to Pr³⁺ (f-f) ions in LuAG host. Furthermore, the energy transfer from Pb²⁺ flux-related impurity to Ce³⁺ (d-f) and Pr³⁺ (f-f) ions also were found in the LuAG:Ce and LuAG:Ce,Pr SCFs. An energy diagram of the Pb²⁺, Pr³⁺ and Ce³⁺ ion levels was constructed, which provides a deeper overview of the mentioned energy transfer processes.