【作者】 黄丽波；

【导师】 程丽红；

【作者基本信息】 大连海事大学 ， 凝聚态物理， 2011， 硕士

【摘要】 在众多稀土有机配合物中,三价铕离子β-二酮配合物凭借着自身优良的发光特性、配体的天线效应和来自铕离子f-f电子跃迁,使得其在激光器、荧光粉和基于场致发光或电致发光的光学数据存储器件上都有广泛的应用。然而,由于过程处理能力差、热稳定性低、机械张力低等特点而限制了纯的β-二酮配合物的应用。将β-二酮配合物掺杂到有机、无机或有机/无机杂化材料中可以作为改善β-二酮化合物应用性质的一个可行方案。静电纺丝技术是唯—利用静电力来使聚合物溶液或者熔融体形成细纤维的方法,是可以将稀土配合物掺杂到有机聚合物中的方法。本文采用均匀沉淀法制备了稀土配合物Eu(DBM)3phen,运用静电纺丝技术制备了复合荧光纤维Eu(DBM)3phen/PS。通过X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)和荧光光谱(PL)等表征手段对样品的物相、形貌和光谱性质进行分析。为了了解Eu3+在稀土配合物和荧光纤维中的荧光性质,利用J-O理论分析了Eu3+在上述两种材料中的光谱性质。从稀土聚合物Eu(DBM)3phen的FE-SEM照片中可以看出,我们得到了具有微球结构的稀土配合物Eu(DBM)3phen,这为形成微球激光器中的“回音廊”模型提供了条件。激发光谱中的宽带远强于Eu3+的f-f跃迁,说明配体DBM和Phen对中心Eu3+具有有效的能量传递。通过J-O理论计算得到的光学跃迁强度参数和内在量子效率。通过对光学增益系数的计算得到了g (λ)/N和P值的依赖关系,说明在5D0→7F2跃迁具有较低的激光运转阈值。当将稀土配合物Eu(DBM)3phen掺杂到PS溶液中,运用静电纺丝技术纺成复合荧光纤维Eu(DBM)3phen/PS,发现激发光谱发生了变化,激发光谱中没有观察到f-f跃迁,发生了非辐射跃迁猝灭。为了进一步研究Eu3+在复合荧光纤维Eu(DBM)3phen/PS中的光学跃迁性质,我们对Eu(DBM)3phen/PS与Eu(TTA)3phen/PS和Eu(DBM)3phen/PMMA这三组光学跃迁强度参数进行了比较。更多还原

【Abstract】 Amongst all lanthanide complexes, europiumβ-diketone complexes exhibit illustrious luminescence properties thanks to the antenna effect of ligands and f-f electron transitions of Eu3+, resulting in important applications in laser, phosphor or optical data storage devices based on photoluminescent, electroluminescent and hole-burning spectroscopies. However, the disadvantages of the pureβ-diketones complexes, low processing ability, poor thermal stability, and low mechanical strength, limited the use of them. Adding the complexes into the organic, inorganic, or organic/inorganic hybrid matrixes my be an viable approach to improve the performance of the (3-diketones complexes. Electrospinning, a spinning technique, is a unique approach using electrostatic forces to produce fine fibers from polymer solutions or melts.Rare earth complexes Eu(DBM)3phen (DBM=dibenzoylmethide;Phen= 1,10-phenanthroline) and fluorescent fiber Eu(DBM)3phen/PS (PS=polystyrene) were studied in this thesis. Mono-dispersed microspheres of ternary complex Eu(DBM)3Phen were prepared through a facile process. Eu(DBM)3phen/PS, a novel fluorescent fiber, was synthesized through electrospinning technology furtherly. The obtained sample was characterized by means of X-ray powder diffraction (XRD) and Scanning Electron Microscope (SEM). In addition, the luminescence properties of the samples were investigated by spectroscopy and the fluorescence decay. According to J-O theory, the optical transition intensity parameters Q(=2,4 and 6) were obtained. The radiative transition properties of 5D0 level, including transition rates, branch ratios and radiative transition lifetime were calculated. As a potential material for microsphere lasers, the optical gain performance for 5D0→7F2 transition was also evaluated.From the FE-SEM image, it can be seen that the prepared sample consists of mono-dispersed microspheres. It should be mentioned that the broad band in the near ultraviolet region is extremely stronger than the f-f transitions of Eu3+. This fact means that the energy transfer from Phen and DBM to Eu3+ is very efficient. According to J-O theory, the optical transition intensity parametersΩ(=2,4 and 6) were obtained to be 20.99×10-20,0.98×10-20 and 1.79×10-20 cm2, respectively. The obtained internal quantum efficiency is around 70%, which is relatively high. The optical gain parameter g(λ)/N depends on the P value. P changes from 0 to 1.0 with a step size of 0.1. It can be seen that the positive gain appears when P gets such a small value around 0.1, thus implying that the pumping threshold for achieving the lasing operation upon 5D0→7F2 transition would be low. This may make the Eu(DBM)3phen a promising material for realizing microsphere lasers.The excitation spectrum of novel fluorescent fiber Eu(DBM)3phen/PS was different from the spectrum of the rare earth complex Eu(DBM)3phen. The optical transition intensity parameters of the Eu(DBM)3phen/PS were compared with Eu(TTA)3phen/PS and Eu(DBM)3phen/PMMA system.更多还原