钇氧化物基质材料的微结构调控及其对发光性能的增强效应研究

发布时间：2018-04-26 14:45

本文选题：氧化钇 + 钒酸钇　；参考：《北京科技大学》2017年博士论文

【摘要】：稀土发光材料因荧光寿命长、光穿透深度大、稳定性好等优点使得稀土发光材料备受研究者的关注并广泛的应用在显示器、激光、生物医学、防伪、信息存储和检测等领域。钇氧稀土化合物例如Y_2O_3、YVO_4具有物理化学稳定性好等优点,成为重要的光致发光基质材料。近年的研究表明,Ln~(3+)离子掺杂的Y_2O_3、YVO_4荧光材料,其性能与形貌具有重大相关性。而近期空心多级结构材料在各个材料领域的优异表现又对此类发光材料的研发提供了重要启示。虽然已有众多科研队伍投身相关研发,然而真正实现以简单的方法制备Y_2O_3、YVO_4多壳层空心球的研究则尚深入探索。因此,以形貌调控为起点,制备发光强度高的钇氧基稀土发光材料,揭示合成机理及形貌与发光性能的依存关系具有重要意义。本文以Y_2O_3与VO_4为基质材料,采用新颖的合成方法,通过制备壳层数可控的、结晶度高的Y_2O_3、YVO_4多壳层空心球,探讨了多壳层空心球与Y_2O_3二维纳米片的形成机制,详细研究了不同形貌的控制合成规律与机理；探讨了形貌对稀土发光材料发光性能的影响,并取得了以下研究成果。(1)利用水热法通过调控反应体系的pH,水热反应温度与时间可以制备出多边形的Y_2O_3纳米片。通过掺杂激活剂Eu~(3+)离子,Y_2O_3:Eu~(3+)纳米片具有较Y_2O_3：Eu~(3+)纳米棒好的红光发射特性。(2)采用简单的水热法合成了Y@C复合碳球。通过调变反应体系中Y(NO_3)3的用量,进而调变Y@C复合碳球中Y~(3+)离子的含量。通过控制Y@C复合碳球的焙烧条件首次得到尺寸均一的并且壳层数高达四层的Y_2O_3多壳层空心球。上转换发光测试结果表明：Y_2O_3：Er~(3+)多壳层空心球的发光强度随壳层数的增加而提高。当Xmol%Yb~(3+)/1mol%Er~(3+)的掺杂量是3mol%/1mol%时,上转换发光强度达到最大值,同时Y_2O_3:3mol%Yb~(3+)/1mol%Er~(3+)空心球的发光强度随着壳层数的增加而增强。Y_2O_3:Yb~(3+)/Er~(3+)多壳层空心球优异的上转换发光性能归因于空心球内部的多级结构对近红外激发光的多级反射。(3)通过系统的合成研究,提出了金属离子-碳球复合模板法制备多组元复合氧化物多壳层空心结构的新路线。以Y@C复合碳球为模板,利用水热条件提高复合碳球模板对V03-复杂阴离子的吸附。通过控制焙烧速率,我们可以得到壳层数可控的、尺寸均一的、结晶度高的壳层数多达三的YV04多壳层空心球。YVO_4:Yb~(3+)/Er~(3+)多壳层空心球显示出较YVO_4:Yb~(3+)/Er~(3+)纳米颗粒非常优越的上转换发光特性,且发光强度随壳层数的增加而增强。通过设计对比实验,进一步揭示出空心球内部的多级结构对近红外激发光具有多级反射作用,因而使材料对近红外激发光的吸收增加,从而促进了YVO_4:Yb~(3+)/Er~(3+)多壳层空心球显著的上转换发光性能的增强。更为重要的是,这种简单的实验方法在其它的复杂氧化物多壳层空心球的合成方面实现了重大突破。
[Abstract]:Rare earth luminescent materials have many advantages, such as long fluorescence life, high light penetration depth and good stability, which make rare earth luminescent materials concerned and widely used in the fields of display, laser, biomedicine, anti-counterfeiting, information storage and detection. Yttrium oxygen rare earth compounds such as Y_2O_3, YVO_4 have the advantages of good physical and chemical stability and so on. Important photoluminescence matrix materials. Recent studies have shown that the properties and morphology of Ln~ (3+) doped Y_2O_3 and YVO_4 fluorescent materials have significant correlation. And the outstanding performance of the hollow multistage structure materials in the field of various materials has provided important inspiration for the development of such materials. The research on the preparation of Y_2O_3 and YVO_4 multi shell hollow spheres is still deeply explored. Therefore, the preparation of yttrium oxygen based rare earth luminescent materials with high luminescence intensity by morphology control is of great significance. It is of great significance to reveal the dependence of synthesis mechanism and morphology and luminescence properties. This paper is based on Y_2O_3 and VO. _4 is a matrix material and a novel synthesis method is used to prepare the multi shell hollow spheres with high crystallinity of Y_2O_3 and YVO_4 multi shell. The formation mechanism of multi shell hollow spheres and Y_2O_3 two-dimensional nanoscale is discussed. The control synthesis rules and mechanisms of different morphologies are studied in detail, and the luminescence properties of the rare earth luminescent materials are discussed. The following research results were obtained. (1) by using the hydrothermal method to regulate the pH of the reaction system, the Y_2O_3 nanoscale of polygon can be prepared by the hydrothermal reaction temperature and time. Through the doping activator Eu~ (3+) ions, Y_2O_3:Eu~ (3+) nanoscale has better red emission characteristics than the Y_2O_3:Eu~ (3+) nanorods. (2) the simple water is used. Y@C composite carbon spheres were synthesized by thermal method. By adjusting the amount of Y (NO_3) 3 in the modulation reaction system, the content of Y~ (3+) ions in Y@C composite carbon spheres was adjusted. By controlling the calcination conditions of the Y@C composite carbon spheres, the size homogeneous and four layers of Y_2O_3 multi shell hollow spheres were obtained for the first time. The upconversion luminescence test results showed that Y_2O_3:Er The luminescence intensity of the ~ (3+) multi shell hollow sphere increases with the number of shell layers. When the doping amount of Xmol%Yb~ (3+) /1mol%Er~ (3+) is 3mol%/1mol%, the upconversion luminescence strength reaches the maximum, while the luminous intensity of the Y_2O_3:3mol%Yb~ (3+) /1mol%Er~ (3+) hollow sphere increases with the number of shell layers and enhances the.Y_2O_3:Yb~ (3+) multi shell hollow. The excellent upconversion luminescence properties of the ball are attributed to the multistage reflection of the near infrared excitation in the hollow spheres. (3) through the study of the system synthesis, a new route for the preparation of multicomponent composite oxide multi shell hollow structures by the metal ion carbon sphere composite template is proposed. The Y@C composite carbon sphere is used as a template and the hydrothermal conditions are improved. The adsorption of V03- complex anions by the composite carbon sphere template. By controlling the roasting rate, we can get the number of shell layers, the size of the shell layer, the number of shell layers with high crystallinity as many as three YV04 multi shell hollow spheres.YVO_4:Yb~ (3+) /Er~ (3+) multi shell hollow sphere, which shows the superior conversion of YVO_4:Yb~ (3+) /Er~ (3+) nanoparticles. The light characteristics and the luminescence intensity are enhanced with the increase of the number of shell layers. Through the design comparison experiment, it is further revealed that the multistage structure in the hollow sphere has multilevel reflection on the near infrared excited light, thus increasing the absorption of the near infrared excitation, thus promoting the significant upconversion of the YVO_4:Yb~ (3+) /Er~ (3+) multi shell hollow sphere. Enhancement of luminescent properties. More importantly, this simple experimental method has achieved a major breakthrough in the synthesis of other complex oxide multi shell hollow spheres.

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ422

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