钕钇共掺氟化钙纳米粉体结构及性能研究

发布时间：2018-06-05 05:27

  本文选题：氟化钙 + 钕　； 参考：《武汉理工大学》2015年硕士论文

【摘要】：纳米材料在一维空间具有小尺寸,微晶由表面原子数目以及电子态的量子约束所影响,从而引起了不同于一般材料所具有的新颖性质,特别是在荧光材料方面,因其发射寿命、荧光量子效率以及浓度猝灭都强烈依赖于粒子的尺寸。CaF2由于其稳定性及非吸湿性成为最具吸引力的氟化物材料,目前有很多关于稀土掺杂氟化物的合成和性能研究,尤其在激光器研究方面。Nd3+离子具有很宽的吸收带,泵浦阈值低、吸收和发射截面都较大,是一种性能优良的增益介质。在激光应用方面,Nd3+离子是最早且最广的,已经可作为100多种基质材料的激活离子。Nd3+离子在808nm附近具有较大的吸收,可实现1064nm波长激光输出,共掺Y3+离子可以形成[Nd3+-Y3+]激活中心,并能取代原有的[Nd3+-Nd3+]团簇体结构,由于[Nd3+-Y3+]团簇体的结构更为复杂,在晶体中产生了丰富的多格位,从而能够降低或防止稀土离子和某些交叉弛豫引起的能量转移而产生的浓度淬灭效应,因而对光学性能的提高有较明显的作用,能够增加发射线宽并能在1.06μm处实现连续波运转。本文采用化学沉淀法合成并采用两种干燥方法制得Nd,Y:CaF2纳米粉体,主要探索不同的反应因素对制备粉体结构和性能的作用。本研究所采用的方法、研究的内容和结果分析表现如下:1.选择化学沉淀法合成了Nd,Y:CaF2纳米粉体,并利用X射线衍射仪、场发射扫描电镜、粒度分析仪、红外光谱仪、吸收光谱仪等测试手段探索了Nd,Y:CaF2纳米粉体的晶格结构、形貌、分散性、粒度分布以及光学性能的影响。研究结果发现,所获得粉体形貌近似成球形,晶粒尺寸在18-25nm范围内,分散性较好,结晶较好,存在杂质离子。2.分别研究不同Nd,Y掺杂含量对CaF2纳米粉体的影响,当固定Y3+掺杂为2at%时,Nd3+的掺杂为4 at%时的颗粒分散性最好、粒度分布最窄。随着Y3+掺杂量的增加,晶胞参数增加,半高宽也逐渐增加,说明结晶度降低,晶格缺陷增加。ICP结果表明,2%Nd,4%Y:CaF2样品Nd3+离子的实际掺杂摩尔百分数为1.98%,Y3+离子的实际掺杂摩尔百分数3.78%,说明稀土离子很好地掺进到了CaF2晶格中。3.研究了不同烧结温度对合成的Nd,Y:CaF2纳米粉体的结构及性能影响,低温(200℃)煅烧时,晶粒尺寸变化不大,当温度继续升高时,颗粒逐渐长大,形貌边界更加清晰,杂质离子的去除效果也更好,吸收强度基本呈上升到趋势,但是温度达到800℃时,吸收强度反而大幅度下降且对杂质离子的排除同600℃相比基本没有多大变化。综合考虑一次粒径和杂质的去除情况,600℃是较好的煅烧温度。4.由于湿凝胶在干燥过程中容易桥接粘连而发生团簇,通过改进工艺,在干燥之前采用正丁醇作为共沸剂进行共沸蒸馏使凝胶中的水分最大限度被去除。共沸蒸馏法获得的粉体团聚程度明显减轻,粒度分布均匀,TG-DSC、FTIR以及吸收光谱均表明其脱水效果比直接干燥法更佳。
[Abstract]:Nanomaterials have small size in one-dimensional space, and the microcrystals are influenced by the number of atoms on the surface and the quantum confinement of electronic states, which leads to novel properties different from those of common materials, especially in fluorescent materials, because of their emission lifetime. Fluorescence quantum efficiency and concentration quenching are strongly dependent on particle size. CaF2 is the most attractive fluorine material due to its stability and non-hygroscopicity. There are many studies on the synthesis and properties of rare-earth doped fluorides. Especially in laser research. Nd3 ion has a wide absorption band, low pump threshold, large absorption and emission cross sections, and is a good gain medium. Nd3 ion is the earliest and most widely used in laser application. It can be used as activator ion. Nd3 ion of more than 100 kinds of matrix material can be absorbed in the vicinity of 808nm, and the laser output of 1064nm wavelength can be realized. Co-doped Y3 ions can form [Nd3 -Y3] activation center and replace the original [Nd3 -Nd3] cluster structure. Because the structure of [Nd3 -Y3] cluster is more complex, there are abundant multi-lattice sites in the crystal. It can reduce or prevent the concentration quenching effect caused by the energy transfer caused by rare earth ions and some cross relaxation, so it can obviously improve the optical properties, increase the emission linewidth and realize the continuous wave operation at 1.06 渭 m. The nanocrystalline ND: y: CaF2 powder was prepared by chemical precipitation and two drying methods. The effects of different reaction factors on the structure and properties of the prepared powder were investigated. The methods, contents and results of this study are as follows: 1. The nanocrystalline ND: y: CaF2 powder was synthesized by chemical precipitation method. The lattice structure, morphology and dispersibility of ND: y: CaF2 nanocrystalline powder were investigated by means of X-ray diffractometer, field emission scanning electron microscope, particle size analyzer, infrared spectrometer and absorption spectrometer. The effect of particle size distribution and optical properties. The results show that the morphology of the powder is approximately spherical, the grain size is in the range of 18-25nm, the dispersion is better, the crystal is better, and the impurity ion. 2. The effect of different NdCY doping content on CaF2 nano-powders was studied. When the doping of Y3 was 2at%, the dispersion of Nd3 particles was the best and the particle size distribution was narrowest when the doping content of Nd3 was 4at%. With the increase of Y3 doping amount, the crystal cell parameters and the half-maximum width increase gradually, which indicates that the crystallinity decreases. The results of lattice defect increase. ICP results show that the actual doped mole percentage of Nd3 ion in the sample of ND: CaF2 is 1.98% and 3.78 mol% of Y3 ion, which indicates that rare earth ions are well doped into CaF2 lattice. 3. The effect of sintering temperature on the structure and properties of the synthesized ND: y: CaF2 nano-powder was studied. The grain size changed little when calcined at low temperature (200 鈩，

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