Post-synthetic lanthanide chelation enables radioluminescence in robust nanoscale MOFs.

Materials capable of converting ionizing radiation into optical emission have been widely explored for imaging and radiation detection, yet the introduction of radioluminescence into chemically modular systems remains less well understood. Here, we report a modular strategy for introducing radioluminescence into chemically robust nanoscale MOFs through post synthetic lanthanide coordination. To our knowledge, this represents one of the first demonstrations of radioluminescence introduced into MOFs via post-synthetic lanthanide coordination. Using the zirconium-based framework UiO-66-(COOH)2 as a stable scaffold, coordination of Eu3+ and Tb3+ ions yields dispersible lanthanide-chelated MOF nanoparticles that retain crystallinity and nanoscale morphology while exhibiting characteristic lanthanide-centered emission under X-ray excitation. Lanthanide incorporation results in enhanced radioluminescent intensity and improved spectral definition relative to the undoped framework, with Tb-chelated materials displaying stronger emission consistent with more efficient linker-to-lanthanide energy transfer. Comparison of photoluminescent and radioluminescent behavior suggests that linker-mediated sensitization plays an important role in lanthanide-centered emission, while additional radioluminescence-specific processes may also contribute under X-ray excitation. Because these systems are designed for nanoscale dispersion and imaging-relevant configurations, this study emphasizes radioluminescent signal generation and spectral characteristics rather than detector-level metrics. Collectively, these results establish post-synthetic lanthanide chelation as a generalizable approach for engineering radioluminescence into robust MOF platforms and expand the accessible design space for X-ray responsive MOF materials.