纳米核壳结构的控制合成及其光电和光学性质研究

发布时间：2018-04-15 20:17

本文选题：稀土离子 + 氟化物　；参考：《南京邮电大学》2015年硕士论文

【摘要】：近年来,稀土离子掺杂的纳米发光材料因其吸收能力强、物理化学性质稳定、发光性质好等优点在各个领域有着广泛的应用前景。但是稀土离子掺杂的纳米发光材料的发光效率还有待提高,而且还很容易被氧化,这也使其在某些方面的应用受到限制。本文以稀土离子掺杂的氟化物为研究对象,通过在氟化物表面包覆氧化物来防止其被氧化,包覆氟化物来提高其上转换发光效率。我们通过水热法合成了NaYbF4:Tm3+纳米颗粒,并采用钛酸四丁酯的水解制备了NaYbF4:Tm3+@TiO2核壳结构,通过XRD、TEM等测试手段对其结构和形貌进行了表征。测试了NaYbF4:Tm3+纳米颗粒随着Tm3+离子浓度不同的上转换发光光谱和NaYbF4:Tm3+@TiO2核壳结构的荧光光谱,结合稀土离能级图分析了Tm3+离子浓度和TiO2壳层对NaYbF4:Tm3+纳米颗粒发光性质的影响。在高沸点溶剂中采用高温裂解法裂解三氟乙酸稀土盐得到单分散的小尺寸的NaGdF4:20%Yb3+,2%Tm3+纳米颗粒和NaGdF4:20%Yb3+,2%Tm3+@NaYF4纳米核壳结构,通过XRD、TEM等测试手段对其结构和形貌进行了表征。研究了Yb3+离子浓度和NaYF4壳层对NaGdF4:20%Yb3+,2%Tm3+上转换发光的影响,结合稀土离子能级图分析了上转换发光机制。研究发现,NaYF4壳层可以很好的提高其上转化发光效率。通过采用高温裂解法裂解三氟乙酸稀土盐得到单分散的小尺寸的NaYF4:20%Yb3+,2%Er3+纳米颗粒和NaYF4:20%Yb3+,2%Er3+@NaYF4核壳结构,再通过正硅酸乙酯(TEOS)水解合成了NaYF4:20%Yb3+,2%Er3+@NaYF4@SiO2纳米核壳结构。通过XRD、TEM等测试手段对其结构和形貌进行了表征。研究了Yb3+离子浓度和NaYF4壳层对NaYF4:20%Yb3+,2%Er3+上转换发光的影响,结合稀土离子能级图分析了上转换发光机制。研究发现NaYF4壳层可以提高其上转换发光效率,SiO2壳层可以很好的保护其不被氧化。
[Abstract]:In recent years, rare earth ions doped nano-luminescent materials have been widely used in various fields because of their strong absorption, stable physical and chemical properties and good luminescence properties.However, the luminescence efficiency of rare earth ions doped nanocrystalline luminescent materials needs to be improved, and it is easy to be oxidized, which limits its application in some aspects.In this paper, rare earth ion doped fluorides are studied to prevent them from being oxidized and to improve their upconversion luminescence efficiency by coating them with oxides.NaYbF4:Tm3 nanoparticles were synthesized by hydrothermal method. The core shell structure of NaYbF4:Tm3 / TIO _ 2 was prepared by hydrolysis of tetrabutyl titanate. The structure and morphology of NaYbF4:Tm3 were characterized by XRD Tem.The upconversion photoluminescence spectra of NaYbF4:Tm3 nanoparticles with different concentrations of Tm3 ions and the fluorescence spectra of the core-shell structure of NaYbF4:Tm3 Tm3 were measured. The effects of Tm3 ion concentration and TiO2 shell layer on the luminescence properties of NaYbF4:Tm3 nanoparticles were analyzed by using rare earth level diagram.In high boiling point solvent, the rare earth salt of trifluoroacetate was pyrolyzed by high temperature pyrolysis method to obtain monodisperse NaGdF4:20%Yb3 2TM 3 nanoparticles and NaGdF4:20%Yb3 2 TM 3 NaYF 4 nanocrystalline core-shell structure. The structure and morphology of these particles were characterized by XRD and TEM.The effects of Yb3 ion concentration and NaYF4 shell layer on upconversion luminescence of NaGdF4:20%Yb3 ~ (2 +) TM ~ (3 +) were studied. The up-conversion luminescence mechanism was analyzed by using rare earth ion energy level diagram.It is found that NaYF _ 4 shell can improve the upconversion luminescence efficiency.By pyrolysis of rare earth salt of trifluoroacetate at high temperature, monodisperse small size NaYF4:20%Yb3 / Er3 nanoparticles and NaYF4:20%Yb3 / 2Er2Er3 / R NaYF4 core-shell structure were prepared by pyrolysis of rare earth salt of trifluoroacetate at high temperature. Then, NaYF4:20%Yb3 2Er3 / NaYF4SiO2 nanocore-shell structure was synthesized by hydrolysis of tetraethyl orthosilicate (TEOS).The structure and morphology were characterized by means of XRD- TEM.The effects of Yb3 ion concentration and NaYF4 shell on upconversion luminescence of NaYF4:20%Yb3 _ 2er _ 3 were studied. The up-conversion luminescence mechanism was analyzed by using rare earth ion energy level diagram.It is found that the NaYF4 shell can improve the upconversion luminescence efficiency and the Sio _ 2 shell can protect it from oxidation.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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