Seed‐Crystal‐Induced Cold Sintering Toward Metal Halide Transparent Ceramic Scintillators

Abstract Scintillators with high spatial resolution at a low radiation dose rate are desirable for X‐ray medical imaging. To challenge the state‐of‐art technology, it is necessary to design large‐area wafers with high light yield, oriented light transport, and reduced light scattering. Here, a seed‐crystal‐induced cold sintering is adopted and a <001>‐textured TPP 2 MnBr 4 (TPP: tetraphenylphosphonium) transparent ceramic is fabricated with a large‐area wafer of 5 cm in diameter, exhibiting high optical transparency of above 68% over the 450–600 nm range. The compelling scintillation performance of the TPP 2 MnBr 4 wafer includes a light yield of ≈78 000 ± 2000 photons per MeV, a low detection limit 8.8 nanograys per second, about 625 times lower than the requirement of X‐ray diagnostics (5500 nanograys per second), and an energy resolution of 17% for high‐energy γ‐rays (662 keV). X‐ray imaging demonstrates a high spatial resolution of 15.7 lp mm −1 . Moreover, the designed material exhibits good retention of the radioluminescence intensity and light yield. This work presents a paradigm for achieving light‐guiding properties with high transparency and large‐area fabrication by grain orientation engineering, and the transparent, textured metal halide ceramic scintillator is expected to provide a route for advancement in the X‐ray imaging of tomorrow.