【作者】 洒盼盼；

【导师】 尹洪宗；

【作者基本信息】 山东农业大学 ， 应用化学， 2010， 硕士

【摘要】 稀土元素原子结构特殊,内层4f轨道未成对电子多、原子磁矩高、电子能级极其丰富,几乎可以与所有元素发生反应,形成多价态、多配位数（3～12个）的化合物,具有许多优异的光、电、磁、核等特性,被称为“现代工业的维生素”和神奇的“新材料宝库”。稀土材料纳米化后,具有许多特性,如小尺寸效应、高比表面效应、量子效应、极强的光、电、磁性质、超导性、高化学活性等,能大大提高材料的性能和功能,可用于新材料的开发,在光学材料、发光材料、晶体材料、磁性材料、电池材料、电子陶瓷、工程陶瓷、催化剂等领域,将发挥重要的作用。本文主要从以下四个方面对稀土进行了研究:1.通过体系Dy³⁺-Gd³⁺-SSA研究了共发光离子Gd³⁺对发光离子Dy³⁺的共发光反应,综合运用紫外可见光谱、荧光光谱、同步散射光谱对共发光反应进行表征,证明了共发光反应的机理。发光中心离子Dy3+属于M*-M型发光,其激发能量既来自于分子内的能量传递也来自于分子间的能量传递;在体系中加入不同离子型的表面活性剂,研究表明,阳离子表面活性剂CTMAB的加入对体系起到了增溶、增敏的作用;考察了Gd³⁺浓度、SSA浓度、pH值对体系荧光、散射光强度的影响,结果表明对于体系Dy³⁺-Gd³⁺-SSA来说,Gd³⁺、SSA最佳浓度分别为3.0×10-4 mol·L^-1、2.0×10-3 mol·L^-1,最佳pH值为8.0。2.应用散射光谱法研究稀土元素La³⁺对Sm³⁺-TFA-TOPO体系的荧光猝灭机理。经分析可推测荧光猝灭主要有三方面原因:（1）胶束是靠表面分子的憎水基的相互吸引缔合而形成的,加入La³⁺后,胶束表面电荷的静电排斥作用不利于胶束形成,络合合物的有机环境被破坏,使荧光减弱;（2）配体竞争减少Sm³⁺的络合物的生成;（3）新的聚集体生成。TFA的跃迁能级与La³⁺的更接近一些,致使由配体向Sm³⁺的能量传递减弱,使荧光减弱产生荧光猝灭。探索了各体系中相关条件对荧光强度的影响,进而找出各体系的最佳形成条件。对于体系Sm³⁺-TFA-TOPO来说,对应荧光强度最强处,Sm³⁺、TFA、TOPO的最佳浓度分别为2.0×10^-5 mol·L^-1、2.0×10-4 mol·L^-1、1.5×10^-4 mol·L^-1 , pH _最佳 =6.4。而体系Sm³⁺-La³⁺-TFA-TOPO,Sm³⁺、TFA、TOPO的最佳浓度分别为2.0×10-5mol·L^-1,3.0×10^-4 mol·L^-1,1.5×10-4 mol·L^-1,pH _最佳=5.8。3.以TTA、phen为相转移剂,DMF为增溶剂高效的将稀土Sm³⁺从水相转移到有机相氯仿中,以硫代乙酰胺的乙醇溶液为硫源成功得到了硫化钐的稀土纳米材料,通过透射电镜、紫外可见光谱、荧光光谱、同步散射光谱等手段对生成的纳米粒子进行了表征,并探索出纳米粒子形成的最佳条件。结果表明,制备的硫化钐纳米材料粒度较小,平均粒度在40⁵0 nm左右,且粒度分布集中,性能稳定。实验证明其形成的最佳条件为Sm³⁺、TTA、phen最佳配比为1:7.5:1.25,相转移过程中有机相与水相最佳体积比为2:1;络合物形成、稀土纳米材料生成的最佳pH值分别为5.46与6.27;络合物相转移、稀土纳米材料形成最佳时间分别为45 min与60 min。4.采用与制备纳米硫化钐相同的相转移法成功制备了硫化铕的纳米材料,通过透射电镜、紫外可见光谱、荧光光谱、同步散射光谱等手段对纳米粒子的生成过程进行了表征,并探索出该纳米材料生成的最佳条件。结果表明,硫化铕纳米材料平均粒度大约在50 nm左右,分布比较分散。其形成的最佳条件为Eu³⁺、TTA、phen最佳配比为1:2.7:1,有机相与水相体积比为2.5:1;络合物生成、稀土纳米材料形成的最佳pH值分别为7.10与7.30;络合物相转移、稀土纳米材料形成最佳时间分别为30 min与120 min。更多还原

【Abstract】 Rare earth elements were praised as“the vitamin of modern industry”, and many rare earth complexes of different valences and coordination number（3～12） have been prepared , which were of good optical、electric、magnetic properties arising from their many unpaired electrons、high atomic magnetic moment and rich electronic energy levels. Rare earth materials of nano structure were of new properties, such as small size effect、high specific surface、quantum effect、superconductivity, and have been extensively applied in a variety of different areas including luminescent materials、crystal materials、magnetic materials、battery materials、electronic ceramics、engineering ceramics、and catalysts et al. The content of this paper consist of four parts as follows:1. The fluorescence enhancement mechanism of Dy³⁺-SSA system by adding Gd³⁺ was studied by the resonance light scattering and fluorescence spectrum. In this paper, the influencing factors including the concentration of Gd³⁺、SSA, pH value as well as surfactants were studied. As a result, the fluorescence and scattering-light intensity of the system Dy³⁺-Gd³⁺-SSA was increased by the surfactant CTMAB, and the optimal experimental conditions were Gd³⁺3.0×10^-4 mol·L^-1、SSA 2.0×10^-3 mol·L^-1、pH 8.0.2. The fluorescence quenching mechanism of Sm³⁺-TFA-TOPO system was studied in the presence of La3+. Resonance scattering-light spectrum indicated that there were three factors: the destroying of micelle, the competition of ligand and the form of new congeries. It analyzed the influence of scattering-light and fluorescence which was caused by different conditions. Then the optimal experimental conditions were studied. Without of La³⁺, the optimal experimental conditions of Sm³⁺-TFA-TOPO system were Sm³⁺ 2.0×10-5 mol·L^-1, TFA 2.0×10-4 mol·L^-1, TOPO 1.5×10^-4 mol·L^-1, pH=6.4 respectively. In the presence of La³⁺, The fluorescence intensity of the Sm³⁺-TFA-TOPO system was maximal on the optimal experimental conditions of Sm³⁺ 2.0×10^-5 mol·L^-1, TFA 3.0×10^-4 mol·L^-1, TOPO 1.5×10^-4 mol·L^-1, pH=5.8.3. Samarium sulfide of nano structure was prepared successfully. Sm³⁺ was transferred from water phase to organic phase by the term of the phase transfer agent of TTA、phen and the solubilizer of DMF, and the samarium sulfide of nano structure developed when the TAA was added as source of S2-. The preparation of nano-particles was characterized by transmission electron microscopy （TEM） and UV-vis spectroscopy、fluorescence and scattering-light spectroscopy. With the aim to attain better samarium sulfide nanoparticles, all kinds of factors were studied. The particle size of samarium sulfide nanoparticles was 40⁵0 nm or so, more uniform, character stability. The optimum conditions was: cSm:cTTA:cphen=1:7.5:1.25, Vorganic phase:Vwater phase =2:1; the optimum pH of the complex and the nanoparticles preparation was 5.46 and 6.27, respectively; the optimum time of phase transferring and nanoparticle generation process was 45 min and 60 min.4. Europium sulfide of nano structure was prepared by the same method as samarium sulfide of nano structure. The preparation of nano-particles was characterized by transmission electron microscopy （TEM） and UV-vis spectroscopy、fluorescence and scattering-light spectroscopy. The particle size of europium sulfide nanoparticles was 50 nm or so, the distribution was dispersed. The optimum conditions was: cEu:cTTA:cphen=1:2.7:1, Vorganic phase:Vwater phase =2.5:1; the optimum pH of complex and the nanoparticles preparation was 7.10 and 7.3, respectively; the optimital time of phase transferring and nanoparticle generation process was 30 min and 120 min.更多还原