稀土下转换纳米荧光粉的可控合成与光学性质研究

发布时间：2018-11-18 20:07

【摘要】：近年来,稀土下转换纳米荧光粉由于其优异的光致发光性能以及在显示器、照明和生物医药等领域的应用而受到广泛关注。因此,选择一种成熟且普遍适用的合成方法实现下转换荧光纳米晶的晶相、形貌和尺寸的调控已成为一个新的科学问题。目前用于制备下转换纳米荧光粉的方法主要包括:热分解、水热、溶胶-凝胶、共沉淀等。其中,水热法和共沉淀法无需苛刻的反应条件且容易控制合成纳米晶的晶相、形貌和尺寸,因而被认为是温和友好的合成方法。本论文选用合适的镧系离子及掺杂浓度在适当的基质中形成具有高质量、单分散性、晶相、形貌和尺寸均一的下转换纳米荧光粉,并对其发光性质和机理进行系统研究。论文的主要研究内容如下:1、采用一步水热法合成了Tb3+,Dy3+或Mn2+单掺CePO4下转换纳米荧光粉。由于Ce3+/Tb3+,Ce3+/Dy3+和Ce3+/Mn2+在CePO4基质中存在有效的能量传递,荧光粉在紫外激发下可以实现可调的多色输出及白光发射。在CePO4基质中率先使用单掺Dy3+或Mn2+的方式获得了白光发射。2、采用水热法制备了单分散的镧系离子(Eu3+,Dy3+或Tb3+)单掺六角晶相NaCeF4纳米晶,并对其激发、发射光谱、寿命衰减曲线、量子产率以及阴极发光等性质以及能量传递机制做了系统研究。在NaCeF4基质中通过调节单掺离子种类及其浓度实现了下转换荧光的多色输出和白光发射。通过单掺Eu3+率先实现了该体系的下转换白光发射,为获得白光提供了简单的方法。3、采用改进的自牺牲模板法(共沉淀法)制备了海胆状的Ce3+/Tb3+共掺GdPO4下转换空心微球。对前驱物Gd(OH)CO3:Ce3+/Tb3+和最终产物GdPO4:Ce3+/Tb3+的晶相,微观结构以及发光性质进行了详细分析和研究。产物的空心结构使其在药物输送以及肿瘤靶向治疗方面有重要的应用前景。
[Abstract]:In recent years, rare earth downconversion nanocrystalline phosphors have attracted wide attention due to their excellent photoluminescence properties and applications in display, lighting, biomedicine and other fields. Therefore, it has become a new scientific problem to select a mature and universally applicable synthesis method to realize the regulation of crystal phase, morphology and size of down-converted fluorescent nanocrystals. The main methods used to prepare down-conversion nano-phosphors include thermal decomposition hydrothermal sol-gel coprecipitation and so on. Hydrothermal method and coprecipitation method are considered to be a mild and friendly method for the synthesis of nanocrystals because they do not require harsh reaction conditions and are easy to control the crystal phase, morphology and size of nanocrystals. In this paper, we select suitable lanthanide ions and doping concentration to form downconversion nanocrystalline phosphors with high quality, monodispersity, crystal phase, uniform morphology and size, and study their luminescence properties and mechanism. The main contents of this thesis are as follows: 1. Tb3, Dy3 or Mn2 doped CePO4 down-converted nano-phosphors were synthesized by one-step hydrothermal method. Due to the effective energy transfer of Ce3 / Tb3, Ce3 / Dy3 and Ce3 / Mn2 in CePO4 matrix, the phosphors can achieve adjustable multicolor output and white emission under UV excitation. White light emission was obtained by mono-doped Dy3 or Mn2 in CePO4 matrix. Secondly, monodisperse Eu3 (Dy3 or Tb3) single-doped hexagonal NaCeF4 nanocrystals were prepared by hydrothermal method, and their excitation and emission spectra were obtained. The properties of lifetime decay curve, quantum yield and cathodoluminescence, as well as the mechanism of energy transfer have been systematically studied. Multicolor output and white light emission of downconversion fluorescence were realized by adjusting the species and concentration of mono-doped ions in NaCeF4 substrate. The downconversion white light emission of the system was first realized by single-doped Eu3, which provided a simple method for obtaining white light. 3. Sea urchin Ce3 / Tb3 co-doped GdPO4 downconversion hollow microspheres were prepared by modified self-sacrificial template (coprecipitation method). The crystal phase, microstructure and luminescence properties of the precursor Gd (OH) CO3:Ce3 / Tb3 and the final product GdPO4:Ce3 / Tb3 were analyzed and studied in detail. The hollow structure of the product makes it promising in drug delivery and tumor targeting therapy.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ422;TB383.1

【共引文献】