Xie Hangqing, Bai Mengke, Wang Anqi, Chen Zi, Chang Feifan, Lian Jiadi, Xu Shiqing
Key Laboratory of Rare Earth Optoelectronic Materials and Devices of Zhejiang Province, Institute of Optoelectronic Materials and Devices, China Jiliang University, Hangzhou 310018, People's Republic of China.
Key Laboratory of Rare Earth Optoelectronic Materials and Devices of Zhejiang Province, Institute of Optoelectronic Materials and Devices, China Jiliang University, Hangzhou 310018, People's Republic of China.
J Colloid Interface Sci. 2024 Dec 15;676:45-51. doi: 10.1016/j.jcis.2024.07.107. Epub 2024 Jul 14.
Triplet exciton is both a luminescence quenching factor and an important luminescence sensitization technology solution, which is widely concerned in the field of optoelectronic materials. Since X-ray excited triplet excitons are dissipated through various pathways, there are still huge difficulties in achieving efficient triplet sensitized emission. Here, the antenna ligand is regulated through the carboxyl group, increasing the steric hindrance between the conjugated groups and improving triplet-enhanced radioluminescence (RL) efficiencies of Tb. The lanthanide metal-organic frameworks (Ln-MOFs) formed by the coordination of Tb with mellitic acid (MA), pyromellitic acid (PMA) and trimesic acid (TMA) under low temperature preparation conditions. Among them, MA-Tb has a longer spacing between conjugated groups than PMA-Tb and TMA-Tb, and its triplet RL is relatively strongest, with a light yield of 28,000 photons MeV. Mechanistic studies revealed that the RL efficiency of Ln-MOFs is related to the π-π stacking effect in the benzene ring. In addition, the application of MA-Tb in the field of X-ray detection was demonstrated. The RL intensity of MA-Tb has a good linear relationship with the X-ray dose rate, and the detection limit for X-ray reaches 82 nGy/s, which is 66 times lower than the typical medical imaging dose. These results will provide a universal strategy for the design of Ln-MOFs scintillator.
三重态激子既是发光猝灭因子，也是一种重要的发光敏化技术解决方案，在光电子材料领域受到广泛关注。由于X射线激发的三重态激子通过各种途径耗散，实现高效的三重态敏化发射仍存在巨大困难。在此，通过羧基调节天线配体，增加共轭基团之间的空间位阻，提高了Tb的三重态增强辐射发光（RL）效率。在低温制备条件下，Tb与均苯四甲酸（MA）、均苯四甲酸（PMA）和均苯三甲酸（TMA）配位形成镧系金属有机框架（Ln-MOFs）。其中，MA-Tb的共轭基团间距比PMA-Tb和TMA-Tb长，其三重态RL相对最强，光产额为28000光子/兆电子伏。机理研究表明，Ln-MOFs的RL效率与苯环中的π-π堆积效应有关。此外，还展示了MA-Tb在X射线检测领域的应用。MA-Tb的RL强度与X射线剂量率具有良好的线性关系，X射线的检测限达到82 nGy/s，比典型的医学成像剂量低66倍。这些结果将为Ln-MOFs闪烁体的设计提供一种通用策略。
