Ma Lijiao, Yuan Mengwei, Liu Chenyu, Xie Linxia, Su Feifei, Ma Shulan, Sun Genban, Li Huifeng
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, China.
Dalton Trans. 2017 Sep 26;46(37):12724-12731. doi: 10.1039/c7dt02662e.
The organic compound of coumarin-3-carboxylic acid (CCA), deprotonated beforehand by NaOH, and the 1-octane sulfonic acid anion (OS) were co-intercalated into the gallery of the layered europium hydroxide (LEuH) via an ion exchange method. Different molar ratios of CCA/OS and NaOH/CCA gave rise to the composites of CCAOS-LEuH (x = 0.8-1.0) showing different emission intensities. In formamide (FM), all composites were delaminated and the formed colloidal suspensions exhibited enhanced red luminescence of Eu in comparison with the OS-LEuH without CCA. Also, the red emissions of the composites were different from the violet emission (421 nm) of free CCA and blue emission (471 nm) of CCA anions in different deprotonation states. The energy levels of CCA and Eu were analyzed to explain the sensitization effect for Eu luminescence. The fluorescence lifetimes of CCAOS-LEuH-1 : 1, CCAOS-LEuH-1 : 1, CCAOS-LEuH-1 : 2, and CCAOS-LEuH-1 : 2 were determined to be 0.705, 0.704, 0.699 and 0.638 ms, respectively, indicating significantly longer lifetimes. The PL quantum yields of ∼10% demonstrate the excellent luminescence properties of the as-prepared CCAOS-LEuH composites. This is the first report on the sensitized luminescence properties of layer Eu ions in LRH composites in the delaminated state. The intriguing red luminescence of delaminated LEuH composites offers a promising approach to achieve efficient luminescent film materials.
香豆素 - 3 - 羧酸（CCA）的有机化合物预先被氢氧化钠去质子化，1 - 辛烷磺酸根阴离子（OS）通过离子交换法共嵌入层状氢氧化铕（LEuH）的层间。不同的CCA/OS摩尔比和NaOH/CCA摩尔比产生了发射强度不同的CCAOS - LEuH（x = 0.8 - 1.0）复合材料。在甲酰胺（FM）中，所有复合材料都发生了分层，与不含CCA的OS - LEuH相比，形成的胶体悬浮液表现出增强的铕红色发光。此外，复合材料的红色发射与不同去质子化状态下游离CCA的紫色发射（421 nm）和CCA阴离子的蓝色发射（471 nm）不同。分析了CCA和Eu的能级以解释对Eu发光的敏化作用。测定了CCAOS - LEuH - 1∶1、CCAOS - LEuH - 1∶1、CCAOS - LEuH - 1∶2和CCAOS - LEuH - 1∶2的荧光寿命分别为0.705、0.704、0.699和0.638 ms，表明寿命显著更长。约10%的PL量子产率证明了所制备的CCAOS - LEuH复合材料具有优异的发光性能。这是关于分层状态下LRH复合材料中层状Eu离子敏化发光性质的首次报道。分层的LEuH复合材料有趣的红色发光为实现高效发光薄膜材料提供了一种有前景 的方法。
