Ultra‐High‐Brightness Ln‐MOFs X‐ray Scintillators by Heavy Atoms, Aggregation Effects, and Hydrogen Bonds Restrict Movement

ABSTRACT The synergistic effect of the “four‐in‐one” strategy, which includes the heavy atoms effect, coordination‐induced emission (CIE), hydrogen bonds locking effect, and efficient antenna effect, was utilized to significantly enhance the light yield of Tb‐SDB‐MOF X‐ray scintillator. Notably, the efficient heavy atoms effect enhances the X‐ray absorption efficiency of Tb‐SDB‐MOF, synergistically with CIE, hydrogen bonds locking restriction of intramolecular motion (RIM), and an energy‐matched antenna effect, producing a scintillation light yield of 69,575 photons MeV −1 – a leading level among lanthanide complexes based X‐ray scintillators. Meanwhile, the Tb‐SDB‐MOF X‐ray scintillator exhibited an ultra‐low detection limit (20.86 nGy/s), which is 264 times lower than the clinical standard, making it an “ultra‐low dose” lanthanide complexes based X‐ray scintillator. Moreover, low‐concentration formic acid vapor selectively quenched the antenna effect of Tb 3+ ions within Eu 0.08 Tb 0.92 ‐SDB‐MOF, resulting in multistage multicolor luminescence switching from gold→brown→orange→deep‐red→red. The Eu‐SDB‐MOF@Tb‐SDB‐MOF heterostructure facilitates the development of an advanced multi‐functional anti‐counterfeiting system by utilizing the highly efficient multicolor luminescence properties of a single crystal. Finally, this work not only opens new avenues for the development of lanthanide complexes based X‐ray scintillators with ultrahigh light yield but also expands new horizons for the expansion of multifunctional lanthanide complexes.