Intensely luminescent materials obtained by combining lanthanide ions, 2,2′-bipyridine, and poly(ethylene glycol) in various fluid or solid environments
Intensely luminescent materials obtained by combining lanthanide ions, 2,2′-bipyridine, and poly(ethylene glycol) in various fluid or solid environments
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DOI：
10.1021/cm991059b
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发表时间：
1999-11-01
影响因子：
8.6
通讯作者：
Lianos, P
中科院分区：
文献类型：
--
作者：
Bekiari, V;Pistolis, G;Lianos, P
稳态发光光谱和发光衰减分析已经被用来研究两个稀土离子（即，EU（3+）和Tb（3+）与聚乙二醇在不存在和存在2，2 '-联吡啶的情况下进行了比较，联吡啶充当近紫外辐射的天线。在不同的聚合物浓度下研究了三种不同的体系，即，水溶液、通过水解四甲氧基硅烷制备的透明复合有机/无机溶胶-凝胶基质和聚合物基质。的发光物种的光物理行为已被研究结合与聚（乙二醇）的内容。在水溶液和二氧化硅基质中，发光强度和衰减时间被发现增加聚合物浓度。2，2 '-联吡啶的加入导致配体与镧系离子之间形成络合物。该复合物通过与聚合物链缔合而稳定。在配体吸收波长（337 nm）处的激发导致配体到金属的能量转移和强发光发射，其特征在于金属的窄带发射。镧系离子与2，2 '-联吡啶形成的配合物具有独特的物理化学性质，在380 nm附近发射出明亮的宽蓝色荧光。冷冻干燥含有镧系元素离子和2，2 ′-联吡啶的中等尺寸的聚（乙二醇）的水溶液产生了当在配体吸收带（337 nm）激发时发射金属的特征发光或当在380 nm激发时发射络合物的特征发光的强发光固体材料。
Steady-state luminescence spectroscopy and luminescence decay analysis have been employed to study the association of two rare earth ions (i.e., EU(3+)and Tb3+) with poly(ethylene glycol) in the absence and in the presence of 2,2'-bipyridine, which acted as an antenna of near-UV radiation. Three different systems have been studied at various polymer concentrations, i.e., aqueous solutions, transparent composite organic/inorganic sol-gel matrixes made by hydrolysis of tetramethoxysilane, and polymer matrixes. The photophysical behavior of the luminescent species has been studied in conjunction with the poly(ethylene glycol) content. In both aqueous solutions and silica matrixes, luminescence intensity and decay time were found to increase by increasing polymer concentration. Addition of 2,2'-bipyridine resulted in complex formation between the ligand and the lanthanide ions. This complex was stabilized by association with the polymer chains. Excitation at the ligand absorption wavelength (337 nm) resulted in ligand-to-metal energy transfer and strong luminescence emission, characterized by the narrow-band emission of the metal. The complex between lanthanide ions and 2,2'-bipyridine possessed its own particular photophysical characteristics and emitted a bright broad blue luminescence with an excitation maximum around 380 nm. Freeze-drying of aqueous solutions of medium size poly(ethylene glycol) containing lanthanide ions and 2,2'-bipyridine produced an intensely luminescent solid material emitting the characteristic luminescence of the metal when excited at the ligand absorption band (337 nm) or the characteristic luminescence of the complex when excited at 380 nm.