Fluoride‐Mediated Host‐Activator Engineering in Homogeneous Lithium Glass Scintillators for Thermal‐Neutron Detection and Imaging

Homogeneous lithium‐aluminosilicate‐glass scintillators offer transparency, scalable fabrication, and compositional flexibility, but their neutron response is limited by defect trapping and activator loading concentration. Here, fluoride‐mediated host‐activator engineering is introduced to overcome these coupled limitations in Ce 3+ ‐activated lithium aluminosilicate glasses. F − preferentially coordinates with Li + and Mg 2+ , preserving the primary Si/Al─O tetrahedral units while reorganizing inter‐tetrahedral linkages. The resulting host‐network reconfiguration suppresses electronic disorder and defect‐mediated trapping, modulates medium‐range Ce‐centered correlations, broadens the viable Ce‐concentration window, and enables efficient excitation capture at ∼9 wt% CeO 2 (twice that of GS20). After 6 Li enrichment, it delivers 8003 photons neutron −1 , an energy resolution of 6.8%, a decay time of 85.06 ns, and a neutron peak‐to‐trough ratio of 77:1. To the best of our knowledge, these values represent the highest light yield and best energy resolution reported for a homogeneous transparent 6 Li‐enriched glass scintillator, achieving single‐digit neutron energy resolution for the first time and approaching the performance of 3 He proportional counters and high‐performance crystalline scintillators. A transparent plate exceeding 2 inches further enables proof‐of‐concept two‐dimensional thermal‐neutron imaging with a system‐level spatial resolution of 1.35 mm, demonstrating the scalability of the glass for position‐sensitive neutron imaging.