Synergistic High‐Z Bismuth and Eu ³⁺ Activators in a Metal–Organic Framework for Efficient X‐Ray and β‐Ray Scintillation

Comprehensive Summary 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 Eu 3+ ⊂Bi‐ndc . In this design, high‐atomic‐number Bi 3+ nodes serve as efficient X‐ray absorbers, while Eu 3+ 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, Eu 3+ ⊂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 Eu 3+ ⊂Bi‐ndc enable high‐resolution X‐ray imaging with a spatial resolution of approximately 7 lp·mm –1 . Remarkably, Eu 3+ ⊂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.