High-Pressure Synthesis, Structural, and Optical Properties of Layered Cerium Borate CeMgB 3 O 7

The present work reports a novel borate layered CeMgB 3 O 7 crystal with an orthorhombic lattice ( Cmme ) as determined by single-crystal X-ray diffraction, which was synthesized through high-pressure solid-state metathesis reaction, marking the first successful preparation of that type of structure under high pressure and high temperature. Using multimodal characterization techniques, including in situ high-pressure synchrotron radiation X-ray diffraction and Raman spectroscopy, the exceptional structural stability of CeMgB 3 O 7 was confirmed up to 34 GPa. X-ray photoelectron spectroscopy measurements and the photoluminescence (PL) spectroscopy further identified a novel pathway for achieving near-infrared emission in Ce-based materials, highlighting the potential of defect engineering to directly activate luminescent centers within the host lattice in CeMgB 3 O 7 . The high-pressure PL spectroscopy indicates that applied pressure effectively modulates the crystal field splitting degree in [CeO 10 ] 17–, imposing a direct and tunable influence on its intrinsic luminescence. These findings advance the understanding of luminescence mechanisms in Ce-based systems and offer new insights for the future design of luminescent materials.