稀土掺杂核—壳型纳米材料的双模式发光

发布时间：2019-02-19 12:06

【摘要】：本文在讨论以氟锆酸盐为基质的纳米材料基础上,构建了可双模式激发的核-壳型纳米发光材料Na3Zr F7:Yb3+,Er3+@GdxZryF7:Eu3+(3x+4y=7),通过结构及光谱分析手段研究了双模式激发下的上/下转换发光规律。本课题中样品的合成方法为溶剂热法。首先,为研究合成温度对Na3Zr F7:Yb3+,Er3+上转换发光的影响,我们制备了单分散的纳米粒子样品,并对样品进行了结构和光谱分析。实验结果表明,在980 nm红外激光激发下,样品均可发出绿色和红色上转换发光,特别是,随着合成温度的升高,样品的上转换发光强度也会迅速提高,这是由于样品的晶粒尺寸逐渐增大所导致的。其次,为研究Eu3+离子掺杂浓度对Gd Zr F7:Eu3+下转换发光的影响,我们合成了不同Eu3+离子掺杂浓度的样品,在273或395 nm光源的激发下,测量了Eu3+离子的特征发光,分析了其发光机制。实验结果表明,Eu3+离子的特征发光强度受其掺杂浓度的影响。本实验中,2 mol%的Eu3+离子掺杂浓度最佳。最后,为了研究Gd3+离子含量(浓度)对材料发光性能的影响,我们合成了Na3Zr F7:Yb3+,Er3+@GdxZryF7:Eu3+(3x+4y=7)核-壳型纳米材料。测量了样品的结构和发光性能,并采用光谱分析等方法研究了其双模式发光。实验结果表明,壳层中Gd3+离子含量对核-壳材料的上转换发光有改善作用,其原因取决于包覆壳层所形成的配位场。此外,在395 nm(直接激发)激发下,Gd3+离子含量变化对Eu3+离子的特征发光存在影响,这是Eu3+离子周围晶场变化所致;而在273 nm(基质激发)激发下,Gd3+离子含量的增加对Eu3+离子的特征发光有积极影响。综上,我们合成了Na3Zr F7:Yb3+,Er3+@GdxZryF7:Eu3+核-壳型纳米材料。该材料具备在红外/紫外双模式激发下实现上/下转换发光的光学特性,在生物医学、太阳能利用、防伪标记等领域具有潜在的应用价值。本文实验结果有望为稀土掺杂纳米核-壳材料未来的实际应用提供必要的理论和实验基础。
[Abstract]:Na3Zr F7:Yb3, Er3 @ GdxZryF7:Eu3 (3x 4y=7), a core-shell nano-luminescent material, which can be excited by dual-mode excitation, was prepared on the basis of a discussion of nano-materials based on fluorozirconate. The upconversion and down-conversion luminescence laws under double mode excitation were studied by means of structure and spectral analysis. The method of sample synthesis in this subject is solvothermal method. Firstly, in order to study the effect of synthesis temperature on upconversion luminescence of Na3Zr F7:Yb3 and Er3, monodisperse nanoparticles were prepared and their structures and spectra were analyzed. The experimental results show that the samples can emit green and red upconversion luminescence under the excitation of 980 nm infrared laser. In particular, with the increase of synthesis temperature, the upconversion luminescence intensity of the samples will increase rapidly. This is due to the gradual increase in the grain size of the sample. Secondly, in order to study the effect of Eu3 ion doping concentration on Gd Zr F7:Eu3 downconversion luminescence, we synthesized samples with different Eu3 ion doping concentrations. The characteristic luminescence of Eu3 ion was measured under the excitation of 273 or 395 nm light source. The luminescence mechanism was analyzed. The experimental results show that the characteristic luminescence intensity of Eu3 ion is affected by its doping concentration. In this experiment, the Eu3 ion doping concentration of 2 mol% is the best. Finally, we synthesized Na3Zr F7:Yb3, Er3 @ GdxZryF7:Eu3 (3x 4y=7) core-shell nanomaterials in order to study the effect of Gd3 ion content (concentration) on the luminescence properties of the materials. The structure and luminescence properties of the samples were measured, and the double mode luminescence was studied by spectroscopic analysis. The experimental results show that the content of Gd3 ion in the shell can improve the upconversion luminescence of core-shell material, and the reason depends on the coordination field formed by the coating shell. In addition, under the excitation of 395 nm (direct excitation), the change of Gd3 ion content has an effect on the characteristic luminescence of Eu3 ion, which is caused by the change of crystal field around Eu3 ion. However, under the excitation of 273 nm, the increase of Gd3 ion content has a positive effect on the characteristic luminescence of Eu3 ion. In summary, we synthesized Na3Zr F7:Yb3, Er3 @ GdxZryF7:Eu3 core-shell nanomaterials. The material has the optical properties of realizing upconversion / down-conversion luminescence under infrared / ultraviolet dual-mode excitation, and has potential application value in biomedicine, solar energy utilization, anti-counterfeiting labeling and so on. The experimental results in this paper are expected to provide the necessary theoretical and experimental basis for the future application of rare earth doped nanocrystalline core-shell materials.
【学位授予单位】：牡丹江师范学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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