Abstract：
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, {Ln4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·xCH3OH (Ln = Sm (1), Eu (2), Tb (3), Dy (4); x = 1-5), based on double thiacalix[4]arene-capped Ln4(μ4-OH)(TC4A)2 nodes. The axially capped Ln4(μ4-OH)(TC4A)2 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 × 106 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 (3) 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.
摘要：
发光稳定性是决定镧系元素发光材料应用的重要因素。设计形成具有可预测的连接模式的扩展框架的发光镧系元素团簇节点可以帮助增强镧系元素络合物的结构稳定性,并因此导致改善的发光稳定性。在这里，我们报道了一系列一维（1D）稀土金属-有机骨架化合物，{Ln4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·xCH3OH(Ln=Sm(1),Eu(2),TB(3),Dy(4)；x=1-5)，基于双硫柳[4]芳烃封端的Ln4(μ4-OH)(TC4A)2节点。轴向加盖的Ln4（μ4-OH）（TC4A）2节点通过甲酸桥等向连接，形成锯齿形1D金属有机骨架（MOF）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稳定的结构和因此优异的发光稳定性。例如,基于Tb的1D-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1.33×106ns。在暴露于水分（在水中浸泡10天）后，其综合发射强度保持在原始值的96.5、94.5和89.4％，高温（150°C），和紫外线（连续辐射15天），分别,表现出优异的发光稳定性。我们采用基于Tb的1D-MOF（3）作为绿色荧光粉，并成功地制造了原型白色发光二极管（LED），在长期运行下具有稳定的发射性能。我们的合成策略允许控制镧系元素节点的连接模式，提供了获得具有改善的发光稳定性的镧系元素MOFs的预测途径。
