Improved Phase Stability and Enhanced Luminescence of Calcite Phase LuBO3:Ce3+ through Ga3+ Incorporation

Transparent Microcomposite Films Based on a Ce-Doped Li6Gd(BO3)3 Scintillator for Radiation Detection

Scintillators are widely used for high-energy radiation detection. Hybrid inorganic-organic composite scintillators with high light yields, high light decay rates, excellent stability, and low costs are in great demand. Here, we report a novel scintillator composed of Ce-doped Li₆Gd(BO₃)₃ (LGBO) microphosphors (MPs) and polymethyl methacrylate for X-ray and thermal neutron detection. The Ce-doped LGBO MPs, fabricated using a facile high-temperature solid-state reaction method, exhibit intense blue light at 416 nm under X-ray and UV excitation and have a high photoluminescence quantum yield of ∼63%. More importantly, the composite scintillator based on these MPs has excellent transparency and luminescence intensity. The luminescence integral intensity of composite scintillators is superior to that of commercial CsI:Na under X-ray excitation, and the light yield under thermal neutron irradiation is 21,000 photons/thermal neutron. The scintillation decay time is found to be below 600 ns. The neutron-gamma signal discrimination and neutron detection efficiency of the composite scintillators are acceptable for practical application. There is an excellent separation between neutron and background events. It represents significant improvements in scintillator performances, especially for reliable thermal neutron scintillators that are likely to improve the data qualities of scientific instruments, including charge-coupled device-based imagers and Anger logic-based position-sensitive detectors in neutron user facilities.

Significant enhancement of scintillation performance by inducing oxygen vacancies in alkali metal ion (A+ = Li+, Na+, K+)-incorporated (Lu, Sc)BO3:Ce

The incorporation of Sc³⁺ can stabilize calcite-phase LuBO₃:Ce³⁺ to grow large-sized single crystals but leads to the significant degradation of scintillation performance. In the present work, alkali metal ion (A⁺ = Li⁺, Na⁺, K⁺)-incorporated (Lu, A, Sc)BO₃:Ce was rapidly synthesized in batches via a high-throughput sol-gel method. The aliovalent substitution of Lu³⁺ with A⁺ is balanced by the generation of oxygen vacancies by forming complexes. Thanks to the increased oxygen vacancies, the luminescence and XEL intensity of (Lu, Li, Sc)BO₃:Ce are significantly enhanced by 2.2 times and 1.9 times, respectively. Further, the incorporation of A⁺ is attributed to the improved transition efficiency of charge carriers. The prepared scintillation screen fabricated with LASBO:Ce and PMMA shows that the spatial resolution can reach 8.6 lp mm^-1, indicating its potential application in efficient and low-cost non-destructive X-ray detection. This work is of great significance in improving the luminescence and scintillation performance of (Lu, Sc)BO₃:Ce single crystals and thin films and their application in the scintillation field.