Scintillators, materials that produce light pulses upon interaction with ionizing radiation, are widely used as radiation detectors. Specifically, scintillators with fast-timing characteristics are essential for achieving high-resolution imaging at the millimetre length scale, particularly in medical imaging and tomography. We demonstrated that composite materials made with fluorescent metal–organic framework (MOF) nanocrystals embedded in a polymer matrix can serve as fast scintillators.[1] In these nanocrystals, the combined effects of the high-Z nodes and the fast diphenylanthracene ligand emitters, arranged at nanometric distances within the framework, enabled rapid and efficient sensitization of ligand fluorescence. The hybrid composite scintillator exhibited a fast time response and an ultra-fast scintillation rise time of ~50 ps, making it a promising material for time-resolved applications. To enhance luminescence efficiency, fast emitters with large Stokes shifts are highly desirable because of the negligible reabsorption of their luminescence. This aim was achieved by exploiting two fluorescent building blocks arranged in MOF nanocrystals.[2-3] We realized hetero-ligand MOFs with a Stokes shift as large as 1.3 eV by co-assembly of scintillating ligands with complementary emission and absorption properties, with high-Z linking nodes. The unique electronic properties of the conjugated ligands allowed for the sensitization of emissive ligands by means of an ultra-fast diffusion-mediated non-radiative energy transfer that can occur at rates in the THz range. This efficient mechanism enabled the instantaneously activation of the ns-lifetime scintillation emission of these MOFs. Remarkably, the efficient antenna mechanism and the elimination of reabsorption improved the scintillation yield of the hetero-ligand MOF by 500% compared to the parent MOF. [1] Nature Phot. 2021, 15, 393; [2] Nature Commun. 2022, 13, 3504; [3] Adv. Funct. Mater. 2024, 34, 2404480.
Perego, J., Bezuidenhout, C., Villa, I., Dhamo, L., Monguzzi, A., Bracco, S., et al. (2025). Fabrication of ultra-fast scintillating MOFs as radiation detectors. Intervento presentato a: Pacifichem 2025 - The International Chemical Congress of Pacific Basin Societies 2025, Honolulu, Hawaii.
Fabrication of ultra-fast scintillating MOFs as radiation detectors
Perego, J.Primo
;Bezuidenhout, C. X.;Villa, I.;Dhamo, L.;Monguzzi, A.;Bracco, S.;Comotti, A.
2025
Abstract
Scintillators, materials that produce light pulses upon interaction with ionizing radiation, are widely used as radiation detectors. Specifically, scintillators with fast-timing characteristics are essential for achieving high-resolution imaging at the millimetre length scale, particularly in medical imaging and tomography. We demonstrated that composite materials made with fluorescent metal–organic framework (MOF) nanocrystals embedded in a polymer matrix can serve as fast scintillators.[1] In these nanocrystals, the combined effects of the high-Z nodes and the fast diphenylanthracene ligand emitters, arranged at nanometric distances within the framework, enabled rapid and efficient sensitization of ligand fluorescence. The hybrid composite scintillator exhibited a fast time response and an ultra-fast scintillation rise time of ~50 ps, making it a promising material for time-resolved applications. To enhance luminescence efficiency, fast emitters with large Stokes shifts are highly desirable because of the negligible reabsorption of their luminescence. This aim was achieved by exploiting two fluorescent building blocks arranged in MOF nanocrystals.[2-3] We realized hetero-ligand MOFs with a Stokes shift as large as 1.3 eV by co-assembly of scintillating ligands with complementary emission and absorption properties, with high-Z linking nodes. The unique electronic properties of the conjugated ligands allowed for the sensitization of emissive ligands by means of an ultra-fast diffusion-mediated non-radiative energy transfer that can occur at rates in the THz range. This efficient mechanism enabled the instantaneously activation of the ns-lifetime scintillation emission of these MOFs. Remarkably, the efficient antenna mechanism and the elimination of reabsorption improved the scintillation yield of the hetero-ligand MOF by 500% compared to the parent MOF. [1] Nature Phot. 2021, 15, 393; [2] Nature Commun. 2022, 13, 3504; [3] Adv. Funct. Mater. 2024, 34, 2404480.
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