High-temperature X-ray detection holds promise potential in practical application with the development of industries. Organic-inorganic manganese-based halide (OIMH) scintillators have aroused 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 kinds of zero-dimensional OIMH scintillators of (4-NH3TBP)MnBr4 (4-NH3TBP = 4-aminobutyl triphenylphosphonium) and (4-DMATBP)MnBr4 (4-DMATBP = (4-(dimethylamino) butyl) triphenylphosphonium) single crystals through rational molecular design. Their abnormal temperature-dependent luminescence behaviors under ultraviolet lamp excitation and X-ray irradiation are observed. Notably, (4-DMATBP)MnBr4 single crystal exhibits 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 function theory calculation further demonstrates that Br-vacancy is responsible for the formation of the trap state. The (4-DMATBP)MnBr4 scintillator exhibits an impressive light yield of 46722 photon MeV−1 at 130 °C, providing the feasibility for application in high-temperature X-ray detection. The transparent single crystal possesses an robust resolution of 42 lp mm−1 in X-ray imaging and shows high imaging quality at high temperatures.
