关于举行阿卜杜拉国王科技大学Omar F. Mohammed教授学术报告会的通知

报告题目：Recent Advances in X-ray Imaging Scintillators

报  告 人：Omar F. Mohammed教授（King Abdullah University of Science and Technology (KAUST)）

邀 请 人：夏志国 教授

报告时间：2023年7月17日（周一）下午15:30-18:00

报告地点：华南理工大学北区科技园一号楼W301会议室

报告摘要：

The high demand for ultralow detection limits of ionizing radiation in medical radiography, high-energy physics, and security screening has driven extensive research on X-ray imaging scintillators.1-4 While high-performance scintillators in the current X-ray imaging market made of ceramics that require harsh and costly preparation and engineering conditions, perovskites and their related structures, heavy-atom engineered thermally activated delayed fluorescence (TADF) and copper nanoclusters with their unique optical behaviors and high X-ray absorption cross section are promising competitors if not alternatives. In this talk, I will present the room-temperature synthesis of colloidal perovskite nanosheets with excellent scintillation performance due to efficient energy transfer processes between stacked thin and thick nanosheet.5 Additionally, I will present the efficient and ultrafast energy transfer strategies between perovskite nanosheets and TADF that successfully produced a reabsorption-free organic X-ray imaging scintillator with a low detection limit of 38.7 nGy/s and outstanding X-ray imaging resolution.6 Similarly, we found that perovskite related Cu and Ag halides as well as Cu-based halide consisting of Cu4I6 nanostructures showed high performance X-ray imaging. For instance, Cu4I6 nanostructures exhibit very low detection limits of 96.4 and 102.1 nGy/s, which are approximately 55 times lower than the dose required for standard medical diagnosis (5.5 μGy s–1) and extraordinary X-ray imaging resolutions exceeding 30 lp/mm, more than double those of the conventional CsI:Tl and Ga2O2S:Tb scintillators.7 Finally, the talk also discusses a novel top-filter-bottom sandwich structure scintillator for high-performance dual-energy X-ray imaging within a single exposure.8 Multi-energy X-ray imaging screens with unprecedented imaging capabilities will be presented and discussed for the first time. This breakthrough research enables clear resolution of different biological tissues based on their corresponding colors and paves the way for the development of new scintillator architectures for dual and multi-energy X-ray imaging with potential applications in medical imaging, industrial monitoring and security screenings.

References

1- J-X. Wang, L. Gutiérrez-Arzaluz, X. Wang, T. He, Y. Zhang, M. Eddaoudi, O. M. Bakr, O. F. Mohammed, Nature Photonics, 16, 869–875 (2022).

2- H. Wang, J-X. Wang, X. Song, T. He, Y. Zhou, O. Shekhah, L. Gutiérrez-Arzaluz, M. Bayindir, M. Eddaoudi, O. M. Bakr, O. F. Mohammed, ACS Central Science, 9, 668-674 (2023).

3- Q. Chen, J. Wu, X. Ou, B. Huang, J. Almutlaq, A. A. Zhumekenov, X. Guan, S. Han, L. Liang, Z. Yi , J. Li, X. Xie, Y. Wang, Y. Li, D. Fan, D. B. L. The, A. H. All, O. F. Mohammed, O. M. Bakr, T. Wu, M. Bettinelli, H. Yang, W. Huang, X. Liu “All-inorganic Perovskite Nanocrystal Scintillators” Nature, 88, 88-93 (2018).

4- J-X. Wang, I. Dutta, J. Yin, T. He, L. Gutiérrez-Arzaluz, O. M. Bakr, M. Eddoudi, K-W. Huang, O. F. Mohammed, Matter, 6, 217-225 (2023).

5- Y. Zhang, R. Sun, X. Ou, K. Fu, Q. Chen, Y. Ding, L-J. Xu, L. Liu, Y. Han, A. V. Malko, X. Liu, H. Yang, O. M. Bakr, H. Liu, O. F. Mohammed, ACS Nano, 13, 2520 (2019).

6- J.-X Wang, X. Wang, L. J. Yin, Gutierrez-Arzaluz, T. He, C. Chen, Y. Han, Y. Zhang, O. M. Bakr, M. Eddaoudi, O. F. Mohammed, ACS Energy Letters, 7, 10-16 (2022).

7- T. He, Y. Zhou, P. Yuan, J. Yin, L. Gutiérrez-Arzaluz, S. Chen, J-X. Wang, S. Thomas, G. N. Alshareef, O. M. Bakr, O. F. Mohammed, ACS Energy Letters, 8, 1362–1370 (2023).

8- W. Shao, T. He, J-X. Wang, Y. Zhou, P. Yuan, W. Wu, Z. Zhang, O. M. Bakr, H. Liang, O. F. Mohammed, ACS Energy Letters, 8, 2505–2512 (2023).

报告人简介：

Dr. Mohammed is Professor of Chemistry and Materials Science & Engineering; and the principal investigator of ultrafast laser spectroscopy and four-dimensional (4D) electron imaging laboratory at KAUST. He earned a Ph.D in Physical and Theoretical Chemistry from Humboldt University of Berlin, Germany. Prior to joining KAUST, Dr. Mohammed was a senior research associate at Caltech, where he worked with Professor Zewail, a Nobel laureate, on developing innovative laser spectroscopic and time-resolved electron imaging techniques. During his time at Caltech, Dr. Mohammed made significant contributions to the profound understanding of the dynamics of photo-generated charge carriers in photoactive materials, and pioneered the development of advanced characterization techniques for studying surface and interfacial dynamics on nanometer and femtosecond scales. The current research activities of Dr. Mohammed are focused on the development of highly efficient solar cells, light-emitting diodes and X-ray imaging scintillators with the aid of ultrafast laser spectroscopy, 4D electron imaging and computational materials.