Advances in Inorganic Single-Crystal Materials for Flat-Panel X-ray Detection: From Conventional Scintillators to Metal Halide Perovskite Systems

As an important nondestructive testing and imaging technique, X-ray detection has broad applications in security inspection, medical imaging, industrial nondestructive testing, national defense, and high-energy physics. The performance of X-ray detectors primarily depends on scintillators and direct-conversion semiconductor materials, whose key figures of merit include high photon yield, fast response, high spatial resolution, excellent stability, and large-area fabrication capability. With the advancement of crystal growth and materials engineering, conventional oxide scintillators and garnet systems have become increasingly mature. In parallel, halides, rare-earth-activated crystals, and emerging metal halide and perovskite single crystals have demonstrated enhanced optoelectronic performance, driving the ongoing development of X-ray detection materials. This paper reviews the research progress of these single-crystal materials for X-ray detection, focusing on crystal growth methods, luminescence mechanisms, and imaging performance. Representative scintillator crystals, direct-conversion semiconductors and emerging metal halide single crystals are discussed as typical examples. Finally, the critical challenges for high-performance X-ray detection single crystals in large-area fabrication and performance optimization are summarized, and future perspectives are discussed.