Design and Radiation-Responsive Applications of Hafnium-Organic Frameworks Based on Aggregation-Induced Emission

The development of functional materials capable of converting high-energy radiation into visible light is crucial for advancing technologies in radiation energy conversion and imaging detection. In this study, a highly luminescent metal-organic framework (Hf-ETTC) was successfully synthesized via a mild solvothermal method utilizing the directed self-assembly of aggregation-induced emission (AIE)-active ligands with hafnium-oxo clusters. The high atomic number of the hafnium centers significantly enhanced the energy absorption efficiency, effectively promoting the radioluminescent behavior of the AIE-active ligands and resulting in an exceptional PLQY of 90.72%. Experimental results revealed that Hf-ETTC embedded in a PDMS matrix exhibited strong luminescence under X-ray excitation and demonstrated sensitivity to radiation dose rates as low as 1.1 μGy s^-1. The radioluminescent performance of Hf-ETTC@PDMS was further validated through the fabrication of a radioluminescent nuclear battery and an X-ray imaging system. The nuclear battery achieved a maximum output power density of 0.19 μW cm^-2 at a dose rate of 5.6 μGy s^-¹. Additionally, flexible X-ray imaging with a spatial resolution of 402 μm was successfully achieved. This work highlights a synergistic strategy combining high-<i>Z</i> Hf elements with the AIE effect, offering valuable insights for the structural design, optical enhancement, and radiation-responsive applications of luminescent metal-organic frameworks.