【作者】 刘晓瑭；

【导师】 谢德民； 石春山；

【作者基本信息】 东北师范大学 ， 无机化学， 2005， 博士

【摘要】 稀土离子共掺杂是稀土发光材料中重要的类型。大量的研究表明共掺体系往往会出现电子转移、能量传递等现象,从而产生异常价态稀土离子和敏化作用。而且不同的基质以及不同的合成方法都直接影响材料的发光性质。到目前为止,共掺体系中稀土离子之间的电子转移的相关研究还是很有限的。稀土离子共掺杂的纳米发光材料的研究更为罕见,然而我们可以预计这类材料必定具有优异特性及广泛的应用前景。 这些具有深远意义的工作也是我们所感兴趣的。在创新性研究中材料体系的选择是至关重要的,仅局限在已有的体系中是不可取的,因此,我们依据以下两条原则建立自己的构想并选择体系:(1)必须避开国外的热门体系和受到专利保护的体系;(2) 选择具有良好开发前景且我们自己已有一定研究基础的化合物体系。为此,我们选择碱金属硼酸盐、碱土金属硼磷酸盐、碱土金属氟化物和复合氟化物作为稀土离子掺杂的基质。通过大量的实验,得到了一些有意义的结论。 首次采用高温固相法在空气中制备了单掺Eu 的M2B4O7 (M=Li, Na, K)系列荧光体,以及共掺 Eu 和 Tb,Eu、Tb 和 Ce 的 MBPO5 :RE (M=Ca, Sr, Ba)系列荧光体;首次在温和的水热条件下合成了 MBPO5:RE (M=Ca, Sr, Ba)、BaBeF4: RE 和 SrMgF4: RE (RE = Eu,Tb)等系列荧光体;首次采用高分子分散的水热法、微乳液法、微乳法-溶剂热的组合法等方法合成了 BaF2纳米粒子和 BaF2:RE(RE=Eu, Tb, Er, Dy, Pr)纳米粒子,重点研究了在CTAB/正丁醇/正庚烷/水溶液体系中微乳液法和组合法的合成方法。 采用 X 射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、热重分析仪(TGA)、傅立叶变换红外光谱仪(FTIR)、电感耦合等离子发射光谱仪(ICP)、荧光光谱仪(LS,PL)等多种测试手段表征了产物的结构特征、研究了产物的发光性质。 结果表明合成条件对产物的结构、性质有显著的影响,掺杂少量的稀土离子不影响产物的结构。高温固相法可以合成多种单掺、共掺稀土离子的发光材料,物相单一,具有较好的发光性质;水热法的合成条件温和,产物纯净,不仅可以合成共掺稀土离子的MBPO5 含氧酸盐体系的荧光体,而且可以合成含氧量极低的共掺稀土离子的 BaBeF4 和SrMgF4 复合氟化物荧光体系;软化学合成方法是制备稀土掺杂的纳米发光材料的首要选择,其中以微乳液法最具价值,CTAB/正丁醇/正庚烷/水溶液体系是制备 BaF2:RE 纳米粒子的良好的微乳体系,微乳法和溶剂热的组合在制备稀土掺杂的氟化物的纳米粒子中也产生了很好的效果。BaF2:RE 纳米粒子均为晶相良好的单相,呈圆形小球体外形,颗粒分布比较均匀,在产物的表面存在少量的吸附水,以及未被洗去的 NO3 离子,在微 -乳液合成法中还有微量的有机物。 在共掺 Eu 和 Tb 的体系中,存在着电子转移和能量传递现象,在同一体系中可以同时观察到 Eu3+、Tb3+和 Eu2+的发射。在共掺 Eu、Tb 和 Ce 的体系中,不仅存在着 Eu 和Tb 之间、Eu 和 Ce 之间的电子转移,而且存在着 Ce3+→Eu2+和 Ce3+→Tb3+之间的能量传递过程,它们之间存在着竞争,在不同的体系中表现出不同的作用方式,Ce 的敏化作用可以调节荧光体的发光性能;通过探讨发光方式和机理,发现性质与结构的关系密切,特别是不同的配位方式对产物的发光性质有决定性的影响。 研究表明可以采用多种方法合成稀土掺杂的纳米 BaF2粒子,不同的方法各具特点,掺杂不同的稀土离子需要采用不同的合成方法。CTAB/n-C4H9OH/n-C7H16/水溶液的相图研究表明不同的体系形成油包水(W/O)反相胶束的范围不同,在组成为 km=1, R=15%的该体系中合成了 BaF2和 BaF2:RE 纳米粒子;BaF2:RE 纳米粒子的发射光谱表明稀土离子均可产生其特征发射并且谱带半高宽都出现宽化现象。 综上所述,本文通过不同的合成方法在不同的基质体系中共掺稀土离子,通过研究其电子转移的特点来研究材料的发光性质,为其在发白光的三基色材料中的应用以及进一步开展理论研究奠定了实验基础;采用多种方法制备氟化物纳米粒子以及不同稀土离子掺杂的氟化物纳米粒子,研究了其发光性质,为其在发光材料特别是光纤通讯中的激光放大方面的应用进行开拓性的工作,为今后更进一步的理论研究和实际应用奠定了可靠的实验基础。更多还原

【Abstract】 Rare earth luminescent materials are one of the most important types of the functionmaterial. They are attracting much attention due to potential and practical application. Onefound that the rare earth ions not only emit their own characteristic emission but also exhibitelectron transfer and energy transfer among conjugate rare earth ions in the co-doped system,then the abnormal valency rare earth ions and the sensitization are produced. Marcus foundedthe theory of the electron transfer, which provides the base for the theory study on the electrontransfer. So far, the study on the electron transfer between the rare earth ions in the co-dopedsystem is still limited. In this kind of system, the properties of the material are depended onthe matrix and the synthesis method. Nanostructured substances have attracted great interestbecause of their uniquely structural properties and advantage in physics and chemistry as wellas they was used as functional materials. It was a regret that this important kind ofluminescent material, which involved with rare earth ions, was not attached enough. We areinterested in all of these works so that a series of luminescent material which co-doped rareearth ions in the different matrix were prepared by different synthesis method. The opticalproperties of them were investigated through the study on the electron transfer. These resultscan establish credible foundation for further studying the potential applications inwhite-light-emitting trichromatic phosphor. In this thesis, the fluoride nanoparticles and thefluorides with doped rare earth ions nanoparticles were prepared by different methods. Theluminescent properties were investigated and establish credible foundation for furtherstudying the potential applications of fluorides doped rare earth ions in laser amplificationmaterials. The phosphors of M2B4O7 : Eu3+(M=Li, Na, K), MBPO5 :RE (M=Ca, Sr, Ba; RE=Eu, Tb,Ce) were synthesized by solid-state reaction for the first time; and the phosphors ofMBPO5:RE (M=Ca, Sr, Ba), BaBeF4: RE and SrMgF4: RE (RE = Eu, Tb) were alsosynthesized by mild hydrothermal method for the first time; furthermore, BaF2 nanoparticlesand BaF2:RE(RE=Eu, Tb, Er, Dy, Pr) nanoparticles were prepared by mild hydrothermalmethod which decentralized by macromolecule, microemulsion, microemulsion- solvothermalmethods. The microemulsions in (CTAB)/n-C4H9OH/n-C7H16/water were studied. They were characterized by means of X-ray powder diffraction, scanning electronmicroscopy, thermogravimetric analysis, infrared spectroscopy and inductively coupledplasma- atomic emission spectrometry. The luminescent properties were investigated by theluminescence spectrometer. The results show that many luminescent materials can be synthesized by solid-statereaction method and the optic properties are very well; among the solution processing routes,the hydrothermal process has been proposed to be an effective method not only for preparingdoped rare earth ions in oxide but also for synthesizing doped rare earth ions in complexfluorides, and the oxygenic content is very low in the fluorides; the soft chemical synthesismethods are the first choice for preparing the nanostructure materials with doped rare earthions, the most important method is microemulsion. The conditions were optimized because the synthesis condition effect strongly thestructure and properties. The electron transfer and energy transfer exist in the co-dopedsystem and the competition between them is occurred, which appeared different status in thedifferent system. The results show that the luminescent properties of these samples depend onthe structure, especially the mode of coordination. The results show that the nanoparticles, which doped rare earth ions, can be synthesizedby many techniques, and the method will be changed with the different doped rare earth ions.XRD confirmed that all the products are pure single phase. SEM show that BaF2:REnanoparticles are spherical particles and uniform grain. DTA-TG analysis and IR analysisshow that there are trace water, NO3 ions and更多还原