Luminescence intensity-tunable X-ray scintillation based on zirconium-based metal-organic frameworks

The low-energy ultraviolet or visible photons can be produced by the interaction between the scintillator materials and ionizing radiation. For this reason, scintillator materials are widely used as radiation detectors, which are prevalently utilized in different applications such as nuclear medicine imaging, homeland security, highenergy physics, oil drilling explorations, etc. Herein, a high-atomic-number (Z) zirconium-based metal-organic framework nanoflower material CJLU-1 (Zr6(mu 3-O)4(mu 3-OH)4(OH)6(TCA)2(H2O)6) (H3TCA = tri-carboxylic acids 4,4 ',4 ''-nitrilotribenzoic acid) was synthesized and can effectively convert X-ray into visible light. CJLU-1 is composed of secondary structural unit hexagonal Zr metal cluster and connected by TCA ligands. The photo luminescence spectra (PL) emission peak and excitation peak of CJLU-1 are at 470 nm and 395 nm respectively. CJLU-1 exhibited radioluminescence (RL) peak with a maximum at 480 nm under steady-state excitation with Xrays. Moreover, by accommodating different guest molecules such as xylene and RhB in the same MOF material, intensity-tunable X-ray scintillation can be facilely achieved, providing a new class of scintillating materials with luminescence intensity tunability. The high-Z hexagonal Zr clusters, which are arranged in an orderly fashion, absorb and interact with the ionizing radiation and sensitize the adjacent organic ligands TCA to produce efficient RL. This work contributes to the development of high-Z zirconium-based MOFs and RL intensity-tunable scintillation materials towards future practical nuclear sensing applications.