Alomar Shorooq A, Wang Jian-Xin, Gutiérrez-Arzaluz Luis, Thomas Simil, Alshareef Husam N, Bakr Osman M, Eddaoudi Mohamed, Mohammed Omar F
Advanced Membranes and Porous Materials Center and KAUST Catalysis Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
Materials Science and Engineering, Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
ACS Appl Mater Interfaces. 2023 Jul 19;15(28):34263-34271. doi: 10.1021/acsami.3c05675. Epub 2023 Jul 10.
X-ray imaging scintillators play a crucial role in medical examinations and safety inspections, making them an essential technology in our modern lives. However, commercially available high-performance scintillators are fabricated exclusively from ceramic materials that require harsh preparation conditions and are costly to produce. Organic scintillators have emerged as a promising alternative due to their transparency and ease of fabrication at a low cost. Unfortunately, organic scintillators suffer from inefficient exciton utilization efficiency, leading to poor performance in X-ray imaging screens and hindering their commercialization. In this study, we explore the use of thermally activated delayed fluorescence (TADF) chromophores (4CzIPN-I and 4CzTPN) to enhance the absorption of ionizing radiation in X-ray imaging screens by an order of magnitude. By leveraging the unique features of TADF chromophores through simultaneously singlet-singlet and triplet-triplet efficient energy transfers at the interface between two different TADF systems, we demonstrate an impressive X-ray sensitivity and radioluminescence intensity. Our time-resolved experiments and density functional theory (DFT) calculations provide further evidence for the effectiveness of this approach. The resulting X-ray imaging screens based on this efficient interfacial energy transfer process in TADF systems exhibit outstanding X-ray imaging resolution of 20 line pairs/mm, the highest resolution reported thus far for organic scintillators. This resolution is at least two times higher than that achieved by commonly used commercial inorganic scintillators in the X-ray imaging market. These findings introduce a new component for greatly improving the performance of organic X-ray imaging scintillators, supporting a wide range of emerging X-ray applications with exceptional spatial resolution.
X射线成像闪烁体在医学检查和安全检测中发挥着至关重要的作用，使其成为我们现代生活中的一项关键技术。然而，市售的高性能闪烁体完全由陶瓷材料制成，这些材料需要苛刻的制备条件且生产成本高昂。有机闪烁体因其透明度高且易于低成本制造而成为一种有前景的替代品。不幸的是，有机闪烁体的激子利用效率低下，导致其在X射线成像屏幕中的性能不佳，阻碍了它们的商业化。在本研究中，我们探索使用热激活延迟荧光（TADF）发色团（4CzIPN-I和4CzTPN）将X射线成像屏幕中电离辐射的吸收提高一个数量级。通过在两种不同TADF系统之间的界面处同时进行单重态-单重态和三重态-三重态高效能量转移，利用TADF发色团的独特特性，我们展示了令人印象深刻的X射线灵敏度和放射发光强度。我们的时间分辨实验和密度泛函理论（DFT）计算为该方法的有效性提供了进一步的证据。基于TADF系统中这种高效界面能量转移过程所制备的X射线成像屏幕具有20线对/毫米的出色X射线成像分辨率，这是迄今为止报道的有机闪烁体的最高分辨率。该分辨率至少比X射线成像市场中常用的商业无机闪烁体所达到的分辨率高两倍。这些发现引入了一种新的组件，可极大地提高有机X射线成像闪烁体的性能，为具有卓越空间分辨率的广泛新兴X射线应用提供支持。
