Scintillators, materials that produce light pulses upon interaction with ionizing radiation, are widely employed in radiation detectors. In advanced medical-imaging technologies, fast scintillators enabling a time resolution of tens of picoseconds are required to achieve high-resolution imaging at the millimetre length scale. Here we demonstrate that composite materials based on fluorescent metal–organic framework (MOF) nanocrystals can work as fast scintillators. We present a prototype scintillator fabricated by embedding MOF nanocrystals in a polymer. The MOF comprises zirconium oxo-hydroxy clusters, high-Z linking nodes interacting with the ionizing radiation, arranged in an orderly fashion at a nanometric distance from 9,10-diphenylanthracene ligand emitters. Their incorporation in the framework enables fast sensitization of the ligand fluorescence, thus avoiding issues typically arising from the intimate mixing of complementary elements. This proof-of-concept prototype device shows an ultrafast scintillation rise time of ~50 ps, thus supporting the development of new scintillators based on engineered fluorescent MOF nanocrystals.
This is a preview of subscription content
Subscribe to Nature+
Get immediate online access to the entire Nature family of 50+ journals
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
Dujardin, C. et al. Needs, trends, and advances in inorganic scintillators. IEEE Trans. Nucl. Sci. 65, 1977–1997 (2018).
Lecoq, P. Development of new scintillators for medical applications. Nucl. Instrum. Methods Phys. Res. A 809, 130–139 (2016).
Conti, M. & Bendriem, B. The new opportunities for high time resolution clinical TOF PET. Clin. Transl. Imaging 7, 139–147 (2019).
Conti, M. Focus on time-of-flight PET: the benefits of improved time resolution. Eur. J. Nucl. Med. Mol. Imaging 38, 1147–1157 (2011).
Conti, M. State of the art and challenges of time-of-flight PET. Phys. Med. 25, 1–11 (2009).
Surti, S. et al. Impact of improved PET spatial and timing resolution on lesion detectability in oncology. J. Nucl. Med. 60, 459 (2019).
Schaart, D. R. et al. LaBr3:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time. Phys. Med. Biol. 55, N179–N189 (2010).
Jones, T. & Townsend, D. History and future technical innovation in positron emission tomography. J. Med. Imaging (Bellingham) 4, 011013 (2017).
Brunner, S. E., Gruber, L., Marton, J., Suzuki, K. & Hirtl, A. Studies on the Cherenkov effect for improved time resolution of TOF-PET. IEEE Trans. Nucl. Sci. 61, 443–447 (2014).
Turtos, R. M. et al. On the use of CdSe scintillating nanoplatelets as time taggers for high-energy gamma detection. npj 2D Mater. Appl. 3, 37 (2019).
Turtos, R. M., Gundacker, S., Auffray, E. & Lecoq, P. Towards a metamaterial approach for fast timing in PET: experimental proof-of-concept. Phys. Med. Biol. 64, 185018 (2019).
Hajagos, T. J., Liu, C., Cherepy, N. J. & Pei, Q. High-Z sensitized plastic scintillators: a review. Adv. Mater. 30, 1706956 (2018).
Gundacker, S., Auffray, E., Pauwels, K. & Lecoq, P. Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET. Phys. Med. Biol. 61, 2802–2837 (2016).
Doty, F. P., Bauer, C. A., Skulan, A. J., Grant, P. G. & Allendorf, M. D. Scintillating metal-organic frameworks: a new class of radiation detection materials. Adv. Mater. 21, 95–101 (2009).
Kitagawa, S., Kitaura, R. & Noro, S.-I. Functional porous coordination polymers. Angew. Chem. Int. Ed. 43, 2334–2375 (2004).
Yaghi, O. M. et al. Reticular synthesis and the design of new materials. Nature 423, 705–714 (2003).
Férey, G. Hybrid porous solids: past, present, future. Chem. Soc. Rev. 37, 191–214 (2008).
Cui, Y., Yue, Y., Qian, G. & Chen, B. Luminescent functional metal–organic frameworks. Chem. Rev. 112, 1126–1162 (2012).
Lustig, W. P. et al. Metal–organic frameworks: functional luminescent and photonic materials for sensing applications. Chem. Soc. Rev. 46, 3242–3285 (2017).
Wang, T. C. et al. Get the light out: nanoscaling MOFs for luminescence sensing and optical applications. Chem. Commun. 55, 4647–4650 (2019).
Wang, C. et al. Synergistic assembly of heavy metal clusters and luminescent organic bridging ligands in metal–organic frameworks for highly efficient X-ray scintillation. J. Am. Chem. Soc. 136, 6171–6174 (2014).
Lu, K. et al. Low-dose X-ray radiotherapy–radiodynamic therapy via nanoscale metal–organic frameworks enhances checkpoint blockade immunotherapy. Nat. Biomed. Eng. 2, 600–610 (2018).
Lu, J. et al. Efficient X-ray scintillating lead(II)-based MOFs derived from rigid luminescent naphthalene motifs. Dalton Trans. 48, 1722–1731 (2019).
Mezenov, Y. A., Krasilin, A. A., Dzyuba, V. P., Nominé, A. & Milichko, V. A. Metal–organic frameworks in modern physics: highlights and perspectives. Adv. Sci. 6, 1900506 (2019).
Abednatanzi, S. et al. Mixed-metal metal–organic frameworks. Chem. Soc. Rev. 48, 2535–2565 (2019).
Lan, G. et al. Nanoscale metal–organic framework hierarchically combines high-Z components for multifarious radio-enhancement. J. Am. Chem. Soc. 141, 6859–6863 (2019).
Paul, L. et al. Roadmap toward the 10 ps time-of-flight PET challenge. Phys. Med. Biol. 65, 21RM01 (2020).
Hiyama, F. et al. X-ray detection capabilities of plastic scintillators incorporated with hafnium oxide nanoparticles surface-modified with phenyl propionic acid. Jpn J. Appl. Phys. 57, 012601 (2017).
Liu, C. et al. Transparent ultra-high-loading quantum dot/polymer nanocomposite monolith for gamma scintillation. ACS Nano 11, 6422–6430 (2017).
Berlman, I. Handbook of Florescence Spectra of Aromatic Molecules (Academic Press, 1971).
Emeline, A. et al. Spectroscopic and photoluminescence studies of a wide band gap insulating material: powdered and colloidal ZrO2 sols. Langmuir 14, 5011–5022 (1998).
Villa, I. et al. Size-dependent luminescence in HfO2 nanocrystals: toward white emission from intrinsic surface defects. Chem. Mater. 28, 3245–3253 (2016).
Yuan, S., Qin, J.-S., Lollar, C. T. & Zhou, H.-C. Stable metal–organic frameworks with group 4 metals: current status and trends. ACS Cent. Sci. 4, 440–450 (2018).
Schaate, A. et al. Modulated synthesis of Zr-based metal–organic frameworks: from nano to single crystals. Chem. Eur. J. 17, 6643–6651 (2011).
Montalti, M., Credi, A., Prodi, L. & Gandolfi, M. T. Handbook of Photochemistry (CRC Press, 2006).
Monguzzi, A. et al. Highly fluorescent metal–organic-framework nanocomposites for photonic applications. Nano Lett. 18, 528–534 (2018).
Aubret, A., Pillonnet, A., Houel, J., Dujardin, C. & Kulzer, F. CdSe/ZnS quantum dots as sensors for the local refractive index. Nanoscale 8, 2317–2325 (2016).
Pope, M. & Swenberg, C. E. Electronic Processes in Organic Crystals and Polymers (Oxford Univ. Press, 1999).
Bosq, N., Guigo, N., Persello, J. & Sbirrazzuoli, N. Melt and glass crystallization of PDMS and PDMS silica nanocomposites. Phys. Chem. Chem. Phys. 16, 7830–7840 (2014).
Lerche, R. A. & Phillon, D. W. Rise time of BC-422 plastic scintillator < 20 ps. In Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference Vol. 1, 167–170 (IEEE, 1991).
Dell’Orto, E., Fasoli, M., Ren, G. & Vedda, A. Defect-driven radioluminescence sensitization in scintillators: the case of Lu2Si2O7:Pr. J. Phys. Chem. C 117, 20201–20208 (2013).
Cowen, A. R., Davies, A. G. & Sivananthan, M. U. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography. Clin. Radiol. 63, 1073–1085 (2008).
Hamada, M. M., Rela, P. R., da Costa, F. E. & de Mesquita, C. H. Radiation damage studies on the optical and mechanical properties of plastic scintillators. Nucl. Instrum. Methods Phys. Res. A 422, 148–154 (1999).
García-Cortés, I. et al. In-situ evaluation of radiation induced optical degradation of candidate scintillator materials for ITER’s gamma and neutron detectors. Fusion Eng. Des. 136, 493–497 (2018).
Davisson, C. M. & Evans, R. D. Gamma-ray absorption coefficients. Rev. Mod. Phys. 24, 79–107 (1952).
Cates, J. W. & Levin, C. S. Evaluation of a clinical TOF-PET detector design that achieves ≤100 ps coincidence time resolution. Phys. Med. Biol. 63, 115011 (2018).
Turtos, R. M., Gundacker, S., Omelkov, S., Auffray, E. & Lecoq, P. Light yield of scintillating nanocrystals under X-ray and electron excitation. J. Lumin. 215, 116613 (2019).
Derenzo, S. E., Weber, M. J., Moses, W. W. & Dujardin, C. Measurements of the intrinsic rise times of common inorganic scintillators. IEEE Trans. Nucl. Sci. 47, 860–864 (2000).
Derenzo, S. E., Choong, W.-S. & Moses, W. W. Fundamental limits of scintillation detector timing precision. Phys. Med. Biol. 59, 3261–3286 (2014).
Gundacker, S. et al. Experimental time resolution limits of modern SiPMs and TOF-PET detectors exploring different scintillators and Cherenkov emission. Phys. Med. Biol. 65, 025001 (2020).
Turtos, R. M. et al. Ultrafast emission from colloidal nanocrystals under pulsed X-ray excitation. J. Instrum. 11, P10015 (2016).
ter Weele, D. N., Schaart, D. R. & Dorenbos, P. Intrinsic scintillation pulse shape measurements by means of picosecond x-ray excitation for fast timing applications. Nucl. Instrum. Methods Phys. Res. A 767, 206–211 (2014).
Financial support from the Italian Ministry of University and Research (MIUR) through grant Dipartimenti di Eccellenza - 2017 ‘Materials for Energy’ is gratefully acknowledged. We acknowledge support from PRIN-20173L7W8K and PRIN-2015CTEBBA-003. We would like to thank I. Supino for her contribution to the synthesis. The work performed at CERN was made in the frame of Crystal Clear Collaboration.
The authors declare no competing interests.
Peer review information Nature Photonics thanks Christine Duval and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Perego, J., Villa, I., Pedrini, A. et al. Composite fast scintillators based on high-Z fluorescent metal–organic framework nanocrystals. Nat. Photonics 15, 393–400 (2021). https://doi.org/10.1038/s41566-021-00769-z