An anti-thermal-quenching organic-inorganic hybrid manganese-based single-crystal scintillator for high-temperature X-ray imaging.

High-temperature X-ray detection holds promising potential in practical applications in the development of industry. Organic-inorganic manganese-based halide (OIMH) scintillators have undergone a research upsurge due to their high X-ray attenuation ability, low preparation cost, outstanding photoluminescence performance, and flexible structures. However, the thermal quenching effects of OIMH materials limit their applications at high temperatures. Herein, we report two zero-dimensional OIMH scintillators, (4-NHTBP)MnBr (4-NHTBP = 4-aminobutyl triphenylphosphonium) and (4-DMATBP)MnBr (4-DMATBP = (4-(dimethylamino)butyl)triphenylphosphonium) single crystals, which were developed through rational molecular design. Their abnormal temperature-dependent luminescence behaviors under ultraviolet lamp excitation and X-ray irradiation are observed. Notably, the (4-DMATBP)MnBr single crystal exhibits an anti-thermal-quenching effect under ultraviolet light and X-ray irradiation, which can be attributed to the participation of intrinsic crystal defects, rigid crystal structure and longer Mn-Mn distance. Density functional theory calculations further demonstrate that Br vacancies are responsible for the formation of the trap state. The (4-DMATBP)MnBr scintillator exhibits an impressive light yield of 46 722 photon per MeV at 130 °C, indicating its feasibility for application in high-temperature X-ray detection. The transparent single crystal possesses a robust resolution of 42 lp mm in X-ray imaging and shows high imaging quality at high temperatures.