Wang Xia, Zhang Zhe, Ma Hui-Li, Ma Zu-Ju, Yuan Meng-Jia, Bian Hai-Jiang, Liu Yi-Cen, Luo Xing-Yun, Ma Fu-Yin, Wang Yan-Long, Yuan Yi-Hui, Wang Ning, Wang Shu-Ao, Liu Wei
School of Environmental and Material Engineering, Yantai University, Yantai, 264005, P.R. China.
Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, 211816, P.R. China.
Angew Chem Int Ed Engl. 2025 Aug 11;64(33):e202505256. doi: 10.1002/anie.202505256. Epub 2025 Jun 24.
Scintillators play vital roles in fields such as medical imaging, high-energy physics, astronomy, and radiation monitoring. Their operational principle, rooted in the excitation of high-energy radiation, underscores that luminescence efficiency in scintillators is fundamentally limited by their capacity to harness triplet excitons. In this context, thermally activated delayed fluorescence (TADF) molecules present a promising avenue, enabling the efficient utilization of triplet excitons through thermally activated up-conversion, thereby advancing the development of superior scintillators. Our investigation reveals a T-blocked TADF mechanism in HTCPE, where efficient singlet-triplet exciton transfer arises from the minimized S-T energy gap (0.18 eV). Unlike conventional TADF molecules, HTCPE features carboxylic acid groups that enable heavy metal coordination to enhance X-ray attenuation. Using tetravalent metals (Zr, Hf, and Th) as nodes and HTCPE as linkers, we fabricated metal-organic frameworks (MOFs) that synergize HTCPE's TADF properties with metal-enhanced radiation absorption. The resulting MOFs show X-ray detection and imaging performances superior to pure HTCPE (20.0 lp mm and 1.15 µGy s for Th-TCPE vs. <14.3 lp mm and 5.01 µGy s for HTCPE), with efficacy correlating to metal atomic number. This work not only broadens TADF molecular diversity through a new energy transfer mechanism and pioneers TADF-MOF integration for advanced radiation detection.
闪烁体在医学成像、高能物理、天文学和辐射监测等领域发挥着至关重要的作用。它们的工作原理基于高能辐射的激发，这突出表明闪烁体的发光效率从根本上受到其捕获三重态激子能力的限制。在这种背景下，热激活延迟荧光（TADF）分子提供了一条有前景的途径，通过热激活上转换实现三重态激子的高效利用，从而推动了高性能闪烁体的发展。我们的研究揭示了HTCPE中的一种T阻断TADF机制，其中高效的单重态-三重态激子转移源于最小化的S-T能隙（0.18 eV）。与传统的TADF分子不同，HTCPE具有羧酸基团，能够实现重金属配位以增强X射线衰减。我们以四价金属（Zr、Hf和Th）为节点，HTCPE为连接体，制备了金属有机框架（MOF），将HTCPE的TADF特性与金属增强的辐射吸收协同起来。所得的MOF表现出优于纯HTCPE的X射线检测和成像性能（Th-TCPE为20.0 lp mm和1.15 µGy s，而HTCPE为<14.3 lp mm和5.01 µGy s），其效能与金属原子序数相关。这项工作不仅通过一种新的能量转移机制拓宽了TADF分子的多样性，还开创了用于先进辐射检测的TADF-MOF集成。
