Molecular Design-Enabled Pyridinium-Based Metal Halide Glass Scintillators with Robust Glass-Forming Ability and...

Organic-inorganic hybrid metal halide (OIMH) glasses represent a promising class of functional materials due to their facile synthesis, high transparency, and composition tunability. However, a significant gap persists in the diversity of applicable glassy material systems and the availability of well-defined structural design guidelines compared to their crystalline counterparts. Herein, we synthesized a series of pyridine-based OIMH crystals exhibiting efficient luminescence and exceptional melting properties. Through systematic benzyl functionalization and phenyl substitution on the pyridinium cation, we have optimized both luminescence efficiency and glass-forming ability (GFA). Among them, (1-Bz-3-PhPy)₂MnBr₄ (1-Bz-3-PhPy = 1-benzyl-3-phenylpyridinium) displays the lowest melting temperature (T_m = 111.9 °C) and the highest glass transition temperature (T_g = 50.3 °C), yielding excellent GFA as indicated by a high T_g/T_m ratio of 0.84. The exceptional GFA is further demonstrated by the glass's remarkable stability, retaining an amorphous state even after annealing at 80 °C for 8 weeks. It also allows for co-melting with other easily crystallizable components, which facilitates the preparation of two-component glasses with precisely tunable radioluminescence properties. These advanced glassy materials provide opportunities for practical X-ray imaging and real-time visualization of multicolor radiation detection, further establishing new design paradigms for OIMH scintillators.