Lu Zixiu, Wang Shujian, Li Guo-Ling, Zhuo Zhu, Zhu Haomiao, Wang Wei, Huang You-Gui, Hong Maochun
School of Rare Earth, University of Science and Technology of China, Ganzhou 341119, China.
Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China.
ACS Appl Mater Interfaces. 2022 Aug 24;14(33):37894-37903. doi: 10.1021/acsami.2c07910. Epub 2022 Aug 15.
Luminescent stability is a vital factor that dictates the application of lanthanide luminescent materials. Designing luminescent lanthanide cluster nodes that form an extended framework with predictable linking patterns may help enhance the structural stability of the lanthanide complexes and hence lead to improved luminescent stability. Herein, we report a series of one-dimensional (1D) rare-earth metal-organic framework compounds, {Ln(μ-OH)(TC4A)(HO)(CHO)(HCOO)(HCOOH)}·CHOH (Ln = Sm (), Eu (), Tb (), Dy (); = 1-5), based on double thiacalix[4]arene-capped Ln(μ-OH)(TC4A) nodes. The axially capped Ln(μ-OH)(TC4A) nodes are connected equatorially by formate bridges to form zigzag 1D-metal-organic framework (MOF) chains, which further assemble into a quasi-two-dimensional (2D) structure via hydrogen bonding. These unique features result in a stable structure and therefore superior luminescent stability. For example, the Tb-based 1D-MOF (3) exhibits intensive green photoluminescence with a quantum yield of 53% and an average decay time of 1.33 × 10 ns. It maintains its integrated emission intensity at 96.5, 94.5, and 89.4% of the original value after being exposed to moisture (soaking in water for 10 days), elevated temperature (150 °C), and UV (15 days of continuous radiation), respectively, demonstrating excellent luminescent stability. We adopt the Tb-based 1D-MOF () as the green phosphor and successfully fabricate a prototype white-light-emitting diode (LED) with stable emission under long-term operation. Our synthetic strategy allows control over the linking pattern of lanthanide nodes, providing a predictive route to obtain lanthanide MOFs with improved luminescent stability.
发光稳定性是决定镧系发光材料应用的关键因素。设计具有可预测连接模式并形成扩展框架的发光镧系簇节点，可能有助于提高镧系配合物的结构稳定性，从而改善发光稳定性。在此，我们报道了一系列基于双硫杂杯[4]芳烃封端的Ln(μ-OH)(TC4A)节点的一维(1D)稀土金属有机框架化合物，{Ln(μ-OH)(TC4A)(HO)(CHO)(HCOO)(HCOOH)}·CHOH (Ln = Sm (), Eu (), Tb (), Dy (); = 1 - 5)。轴向封端的Ln(μ-OH)(TC4A)节点通过甲酸桥在赤道方向连接，形成锯齿状的一维金属有机框架(MOF)链，该链通过氢键进一步组装成准二维(2D)结构。这些独特的特征导致了稳定的结构，因此具有优异的发光稳定性。例如，基于Tb的一维MOF(3)表现出强烈的绿色光致发光，量子产率为53%，平均衰减时间为1.33×10 ns。在分别暴露于湿气(在水中浸泡10天)、高温(150°C)和紫外线(连续辐射15天)后，其积分发射强度分别保持在原始值的96.5%、94.5%和89.4%，显示出优异的发光稳定性。我们采用基于Tb的一维MOF()作为绿色磷光体，并成功制备了一种在长期运行下具有稳定发射的白光发光二极管(LED)原型。我们的合成策略允许控制镧系节点的连接模式，为获得具有改善发光稳定性的镧系MOF提供了一条可预测的途径。
