Synthesis of ionic liquid-based hybrid manganese halides for high-resolution X-ray imaging

Low-dimensional lead-free metal halide materials have garnered significant attention from researchers due to their unique optical properties. Manganese(II)-based metal halides have emerged as promising candidates for use in white light-emitting diodes (LEDs) and scintillator applications. This work introduces two instances of manganese bromide compound crystals characterized by zero-dimensional structures, which have been synthesized utilizing pyridinium-based ionic liquids as organic ligands, designated as (C 10 H 16 N) 2 MnBr 4 (CP1, C 10 H 16 N = 1‑butyl‑3-methylpyridine cation) and (C 10 H 16 N) 2 MnBr 4 (CP2, C 10 H 16 N = 1‑butyl‑4-methylpyridine cation). Upon excitation with ultraviolet (UV) light, the CP1 and CP2 crystals exhibited green photoluminescence, with quantum yields of photoluminescence (PLQY) measured at 47.59 % for CP1 and 68.31 % for CP2, respectively. The zero-dimensional manganese bromide compound CP2, which has been synthesized utilizing pyridine-based ionic liquids, demonstrates potential as an X-ray imaging scintillator. It exhibits a light yield of 17,337 photons/MeV and a detection limit of 343 nGy air /s. The spatial resolution of the CP2@PVDF flexible film is as high as 8.3 lp/mm. This work demonstrates that pyridine-based ionic liquids, when used as organic ligands, provide innovative design concepts for the synthesis of novel manganese-based halides.