Synergistic High-Z Bismuth and Eu³⁺ Activators in a Metal–Organic Framework for Efficient X-Ray and β-Ray Scintillation

Radiation scintillators that combine high sensitivity, stability, and multimodal detection capability are highly desirable for advanced radiation imaging and monitoring. Herein, we report a rational lanthanide-doping strategy to construct a high-performance metal–organic framework (MOF) scintillator, namely Eu³⁺⊂Bi-ndc. In this design, high-atomic-number Bi³⁺ nodes serve as efficient X-ray absorbers, while Eu³⁺ ions act as isolated luminescent activators, and rigid 2,6-naphthalenedicarboxylate (ndc^2–) ligands function as effective antennae to facilitate energy transfer and suppress non-radiative relaxation. Under X-ray excitation, Eu³⁺⊂Bi-ndc shows intense radioluminescence with a low detection limit of 2.5 μGy·s^–1, a light yield of 25,695 photons MeV^–1, and outstanding irradiation stability. Flexible scintillating films fabricated from Eu³⁺⊂Bi-ndc enable high-resolution X-ray imaging with a spatial resolution of approximately 7 lp·mm^–1. Remarkably, Eu³⁺⊂Bi-ndc also exhibits measurable β-ray–induced scintillation, representing the first example of a lanthanide-containing MOF functioning as a β-ray scintillator. This study advances a synergistic high-Z/lanthanide MOF paradigm that bridges X-ray and β-ray scintillation, paving the way for novel multifunctional radiation detectors.