Band Gap and Defect Engineering Enhanced Scintillation from Ce³⁺-Doped Nanoglass Containing Mixed-Type Fluoride Nanocrystals

Much can be learned from the research and development of scintillator crystals for improving the scintillation performance of glasses. Relying on the concept of “embedding crystalline order in glass”, we have demonstrated that the scintillation properties of Ce³⁺-doped nanoglass composites (nano-GCs) can be optimized via the synergistic effects of Gd³⁺-sublattice sensitization and band-gap engineering. The nano-GCs host a large volume fraction of KY_xGd_1-xF₄ mixed-type fluoride nanocrystals (NCs) and still retain reasonably good transparency at Ce³⁺-emitting wavelengths. The light yield of 3455 ± 20 ph/MeV is found, which is the largest value ever reported in fluoride NC-embedded nano-GCs. A comprehensive study is given on the highly selective doping of Ce³⁺ in the NCs and its positive effect on the scintillation properties. The favorable influence of the Y³⁺/Gd³⁺ mixing on the suppression of defects is accounted for by density functional theory and borne out experimentally. As a proof-of-concept, X-ray imaging with a good spatial resolution (7.9 lp/mm) is demonstrated by employing Ce³⁺-doped nano-GCs. The superior radiation hardness, repeatability, and thermal stability of the designed scintillators bode well for their long-term practical applications.