Lead-free scintillators based on pyridine manganese halide for X-ray imaging

Metal halide with high luminescence property have emerged as the novel candidate materials for X-ray detection and imaging. However, the toxicity of some metal cations, such as Pb 2+ , limits its further widespread application. In this work, a new of lead-free pyridine manganese halide (C 5 H 6 N) 2 MnBr 4 was synthesized by the solution-processed method in room temperature. The research results show (C 5 H 6 N) 2 MnBr 4 has a typical structure of tetrahedral coordination related to d-d transition, which has a strong green emission at 520 nm with a full width at half maximum (FWHM) of 45 nm. (C 5 H 6 N) 2 MnBr 4 exhibits high photoluminescence quantum yields (PLQYs) of 59.36%, appreciable light yield of 15400 photons/MeV which is much higher than lead halide, relative short PL decay lifetime (247 μs) which is shorter than previous reported manganese halide and ultrashort RL decay time (12.24 ns). Finally, the performance of (C 5 H 6 N) 2 MnBr 4 Scintillators was verified via X-ray imaging, and clear X-ray image was obtained. (C 5 H 6 N) 2 MnBr 4 scintillators are eco-friendly and easy-synthesize while it has many superior performances: large stokes shift to reduce self-absorption of light; high PLQY to enhance scintillation performances; short decay lifetime to improve response. Thus, (C 5 H 6 N) 2 MnBr 4 shows great potential as next generation of scintillators and this work provides a new way for the preparation of simple and low-cost metal halide scintillators. • Pyridine halide manganese microcrystals and single crystals are synthesized by solution-processed method. • Pyridine cations lead to the longer Mn–Mn distance, suppressing the motion of luminescence centers and improve PLQY via decreasing non-radiative transition. • The RL of (C 5 H 6 N) 2 MnBr 4 exhibits ultrashort RL decay lifetime.