Rare-earth halide perovskite-like scintillators for X-ray detection and imaging

Scintillator-based X-ray detection technologies play an irreplaceable role in national security, medical diagnostics, and industrial non-destructive testing due to their broad dynamic response range, large effective imaging area, low maintenance requirements, and high operational reliability. In recent years, metal halide emitters with perovskite or perovskite-like structures have attracted extensive attention, among which rare-earth halides have shown remarkable scintillation characteristics, including high radiation conversion efficiency, tunable emission spectra, and excellent stability. These advantages arise from their structural diversity and rich photophysical properties, positioning them as strong candidates for next-generation scintillators. In this review, we provide a comprehensive overview of recent advances in rare-earth halide scintillators for X-ray detection and imaging. We first clarify the fundamental physical mechanisms governing the interaction between X-rays and rare-earth halide scintillators, along with the complete scintillation process. We then systematically summarize emerging classes of rare-earth halide scintillation materials, including fully inorganic compounds, organic-inorganic hybrids, and rare-earth-ion-doped systems, with emphasis on their design principles and strategies for modulating scintillation performance. In addition, we highlight the potential of these materials in high-resolution imaging, multimodal imaging, and X-ray photodynamic therapy. Finally, we identify the key challenges that currently constrain progress in this field and propose future research directions aimed at advancing rare-earth halide scintillator technologies.