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Organic phosphors with bright triplet excitons for efficient X-ray-excited luminescence

Abstract

Materials that exhibit X-ray-excited luminescence have great potential in radiation detection, security inspection, biomedical applications and X-ray astronomy1,2,3,4,5. However, high-performance materials are almost exclusively limited to ceramic scintillators, which are typically prepared under high temperatures6. Herein we report metal-free organic phosphors based on a molecular design that supports efficient triplet exciton harvesting to enhance radioluminescence. These organic scintillators exhibit a detection limit of 33 nGy s–1, which is 167 times lower than the standard dosage for X-ray medical examination and we demonstrate their potential application in X-ray radiography. These findings provide a fundamental design principle and new route for the creation of promising alternatives to incumbent inorganic scintillators. Furthermore, they offer new opportunities for development of flexible, stretchable X-ray detectors and imagers for non-destructive radiography testing and medical imaging.

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Fig. 1: A schematic representation of the X-ray-excited luminescence in purely organic materials.
Fig. 2: Photoluminescence and X-ray-excited luminescence characterization of iodine-containing isomers in the crystalline state under ambient conditions.
Fig. 3: Proposed mechanism of X-ray-excited luminescence in purely organic molecules at room temperature.
Fig. 4: Versatile purely organic molecules for X-ray-excited luminescence and primary demonstration for radiography under ambient conditions.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request. Source data are provided with this paper.

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Acknowledgements

This work is supported by the National Key R&D Program of China (grant no. 2020YFA0709900), the National Natural Science Foundation of China (grant nos. 21975120, 21875104, 91833304, 21973043, 51673095 and 61935017), the Joint Research Funds of Department of Science and Technology of Shaanxi Province and Northwestern Polytechnical University (grant no. 2020GXLH-Z-006), Natural Science Fund for Distinguished Young Scholars of Jiangsu Province (grant no. BK20180037), China National Postdoctoral Program for Innovative Talents (grant no. BX20200278), Projects of International Cooperation and Exchanges NSFC (grant no. 51811530018), the Fundamental Research Funds for the Central Universities, Agency for Science, Technology and Research (A*STAR) under its AME program (grant nos. A1883c0011 and A1983c0038), and the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award no. OSR-2018-CRG7-3736.

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Authors

Contributions

X.W., H.S., Z.A., X.L and W.H. conceived the experiments. X.W., H.S., Z.A., X.L. and W.H. prepared the paper. X.W., H.S., W.Y., L.S., X.Y., G.Y, Z.Z., M.S., C.L., J.Z. and C.D. were primarily responsible for the experiments. J.Z., X.O., Y.T., Q.C., Y.W. and H.Y. were responsible for the X-ray related experiments. H.W., Q.W. and W.J. performed lifetime and quantum yield measurements. H.M. and X.J. contributed to time-dependent density functional theory calculations calculations. Y(M).Y. conducted photoconductive gain measurements. X.X., J.W., Q.C. and G.Z. gave suggestions of conceptual ideas and language improvements for the manuscript. All authors contributed to the data analyses.

Corresponding authors

Correspondence to Zhongfu An or Xiaogang Liu or Wei Huang.

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The authors declare no competing interests.

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Peer review information Nature Photonics thanks the anonymous reviewers for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–12, Tables 1–5, Equations 1–10, Scheme 1 and references.

Crystallographic Data 1

The crystallographic data of o-ITC.

Crystallographic Data 2

The crystallographic data of m-ITC.

Crystallographic Data 3

The crystallographic data of p-ITC.

Source data

Source Data Fig. 2

Numerical data used to generate Fig. 2.

Source Data Fig. 3

Numerical data used to generate Fig. 3.

Source Data Fig. 4

Numerical data used to generate Fig. 4.

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Wang, X., Shi, H., Ma, H. et al. Organic phosphors with bright triplet excitons for efficient X-ray-excited luminescence. Nat. Photonics 15, 187–192 (2021). https://doi.org/10.1038/s41566-020-00744-0

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