稀土掺杂钙钛矿型复合氧化物的制备及性能

发布时间：2018-01-24 18:40

  本文关键词： 稀土离子 钙钛矿 纳米晶 发光 水热法　出处：《黑龙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：稀土离子因其具有稳定的物理和化学性质、丰富的能级结构、较长的能级寿命,可以掺杂到适合的基质材料里面作为发光中心,通过蓝光或近紫外光的激发,得到丰富的光致发光特性。稀土功能性材料中十分重要的一类就是稀土发光材料,如今稀土发光材料已经被广泛应用于节能照明以及显示等领域中。由于稀土离子具有独特的4f电子组态、4f5d电子组态及电荷迁移带结构,因此其发光特性对其掺杂的基质材料的结构、组成等性质有很强的依赖性。因此,为了提高材料的荧光性能,我们现在的一个重要的研究方向就确立在寻找有利于稀土离子掺杂的新型的基质材料。钙钛矿型复合氧化物具有层状结构,并且性能优异,近年来使人们对其的研究产生越来越大的关注。此外,由于钙钛矿型复合氧化物包含的晶体种类十分丰富,并且允许大量离子替换,因此使得稀土掺杂钙钛矿型复合氧化物的光学性质具有巨大的研究价值和应用前景。在本论文中,我们采用简单易行的水热合成路线,摸索最佳合成条件,制备了一系列稀土离子掺杂钙钛矿型复合氧化物的纳米晶,并研究了掺杂离子(以Eu3+为主)在不同的钙钛矿基质中的光致发光特性。论文的主要研究内容如下:(1)BaTiO3:Eu3+/Eu2+纳米晶的可控合成及光致发光特性研究。本文采用水热法和随后的煅烧处理的方法成功地合成出了四方相BaTiO3:Eu纳米晶。通过X射线衍射、拉曼光谱、透射电子显微镜、扫描电子显微镜对其形貌和纳米结构进行了研究。并且对BaTiO3:Eu纳米晶光致发光特性进行了详细研究。在398nm激发下,Eu2+离子和Eu3+离子的发射均被观察到,这表明在BaTiO3:Eu纳米晶中Eu2+离子和Eu3+离子共存。尤其是,在BaTiO3:Eu中Eu2+的发射光谱带随着Eu浓度的增加而变宽。当Eu的浓度为0.5mol%时,可以观察到5D0→7F0和5D1→7F0的发射。此外,在537nm激发下,发射强度随Eu浓度的增加而增大。(2)Bi2MoO6:Ln3+纳米晶的光致发光及光催化活性研究。通过水热法合成了片状的Bi2MoO6:Ln3+纳米晶。Bi2MoO6:Ln3+纳米晶的晶粒大小随着在反应液中增加Ln3+的含量而变化。对Bi2MoO6:Ln3+纳米晶的光致发光性能也进行了详细的研究。在Bi2MoO6:Eu3+纳米晶的发射光谱中,5D0→7F2的发射远远强于5D0→7F1。当激发波长为467nm时,发射强度最强。随着Eu3+离子浓度的增加,Eu3+的发射强度也增大,一直增加到Eu3+含量为50mol%,然后下降。在618nm监测下,Bi2MoO6:Eu3+(30%)/Gd3+的激发光谱中,当Gd3+浓度为10%或20%时,主要为7F0→5D2(467nm)的发射。当Gd3+的浓度为30%时,主要为7F0→5D1(538nm)的发射。此外,Bi2MoO6:Eu3+的光催化活性通过在可见光下降解罗丹明B的实验来进行研究的。可以观察到最好的光催化活性是当Eu3+浓度为1%时。
[Abstract]:Because of its stable physical and chemical properties, rich energy level structure and long energy level lifetime, rare earth ions can be doped into the suitable substrate as the luminescence center through blue or near ultraviolet excitation. Rich photoluminescence properties have been obtained. Rare earth luminescent materials are one of the most important functional materials. Nowadays, rare earth luminescent materials have been widely used in the fields of energy saving lighting and display. Due to the unique 4f electron configuration, 4f5d electron configuration and charge transfer band structure, rare earth ions have been widely used. Therefore, its luminescent properties are strongly dependent on the structure, composition and other properties of the doped matrix materials. Therefore, in order to improve the fluorescence properties of the materials. One of our important research directions is to find new matrix materials which are favorable to rare earth ions doping. Perovskite-type composite oxides have layered structure and excellent performance. In recent years, more and more attention has been paid to the research of perovskite-type oxides. In addition, the perovskite-type composite oxides contain a large number of crystal types and allow a large number of ions to be replaced. Therefore, the optical properties of rare-earth doped perovskite-type composite oxides have great research value and application prospect. In this paper, we use a simple and easy hydrothermal synthesis route to explore the best synthesis conditions. A series of rare earth ions doped perovskite-type composite oxide nanocrystals were prepared. The photoluminescence properties of doped ions (mainly Eu3) in different perovskite substrates were studied. The controllable synthesis and photoluminescence properties of BaTiO3:Eu3 / Eu2 nanocrystals were studied. The tetragonal BaTiO3 was successfully synthesized by hydrothermal method and subsequent calcination treatment. EU nanocrystalline. X-ray diffraction. Raman spectroscopy, transmission electron microscope. The morphology and nanostructure of BaTiO3:Eu nanocrystalline were studied by scanning electron microscope. The photoluminescence characteristics of BaTiO3:Eu nanocrystalline were studied in detail. The emission of Eu2 ion and Eu3 ion were observed, which indicated that Eu2 ion and Eu3 ion co-existed in BaTiO3:Eu nanocrystalline, especially in BaTiO3:Eu nanocrystalline. The emission bands of Eu2 in BaTiO3:Eu become wider with the increase of EU concentration. When EU concentration is 0.5 mol%, 5D0 can be observed. 鈫，

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