Zero-Dimensional Organic–Inorganic Hybrid Manganese Halides for Low-Temperature X-Ray Imaging Scintillators

Developing high-performance, easily synthesized, and thermally adaptable scintillation materials is essential to meet increasing industrial demand and drive innovation in X-ray imaging technology. This work presents the synthesis and fabrication of zero-dimensional (0D) green light-emitting (KC)2MnX4 (X = Br, Cl) imaging scintillators with near-unity photoluminescence quantum yield. Experimental and computational results reveal that intense green emission arises from intrinsic d-d transitions in Mn2+ ions. Additionally, this work explores the impact of temperature variations on the optical response of these materials. At low temperatures, emission intensity increases under ultraviolet excitation and X-ray irradiation. The practical application of (KC)2MnX4 (X = Br, Cl) imaging scintillators is also examined. Large-area scintillators demonstrated a high light yield of 20,000 photons/MeV and a low detection limit of just 180 nGy/s, which is 30 times lower than the typical dose required for medical radiography (5.5 μGy/s). Moreover, radioluminescence is further enhanced at reduced temperatures, decreasing the detection limit to 120 nGy/s at 80 K. Furthermore, Mn(II) hybrid bromide scintillators achieved an imaging resolution of 20 lp/mm, capturing highly detailed X-ray images of various objects. This work provides new insights into the development of low-temperature X-ray imaging scintillators based on Mn(II) organic–inorganic halides, expanding their potential for advanced X-ray imaging applications.