本文關鍵詞： 稀土離子 鈣鈦礦 納米晶 發(fā)光 水熱法　出處：《黑龍江大學》2015年碩士論文　論文類型：學位論文

【摘要】：稀土離子因其具有穩(wěn)定的物理和化學性質、豐富的能級結構、較長的能級壽命,可以摻雜到適合的基質材料里面作為發(fā)光中心,通過藍光或近紫外光的激發(fā),得到豐富的光致發(fā)光特性。稀土功能性材料中十分重要的一類就是稀土發(fā)光材料,如今稀土發(fā)光材料已經被廣泛應用于節(jié)能照明以及顯示等領域中。由于稀土離子具有獨特的4f電子組態(tài)、4f5d電子組態(tài)及電荷遷移帶結構,因此其發(fā)光特性對其摻雜的基質材料的結構、組成等性質有很強的依賴性。因此,為了提高材料的熒光性能,我們現在的一個重要的研究方向就確立在尋找有利于稀土離子摻雜的新型的基質材料。鈣鈦礦型復合氧化物具有層狀結構,并且性能優(yōu)異,近年來使人們對其的研究產生越來越大的關注。此外,由于鈣鈦礦型復合氧化物包含的晶體種類十分豐富,并且允許大量離子替換,因此使得稀土摻雜鈣鈦礦型復合氧化物的光學性質具有巨大的研究價值和應用前景。在本論文中,我們采用簡單易行的水熱合成路線,摸索最佳合成條件,制備了一系列稀土離子摻雜鈣鈦礦型復合氧化物的納米晶,并研究了摻雜離子(以Eu3+為主)在不同的鈣鈦礦基質中的光致發(fā)光特性。論文的主要研究內容如下:(1)BaTiO3:Eu3+/Eu2+納米晶的可控合成及光致發(fā)光特性研究。本文采用水熱法和隨后的煅燒處理的方法成功地合成出了四方相BaTiO3:Eu納米晶。通過X射線衍射、拉曼光譜、透射電子顯微鏡、掃描電子顯微鏡對其形貌和納米結構進行了研究。并且對BaTiO3:Eu納米晶光致發(fā)光特性進行了詳細研究。在398nm激發(fā)下,Eu2+離子和Eu3+離子的發(fā)射均被觀察到,這表明在BaTiO3:Eu納米晶中Eu2+離子和Eu3+離子共存。尤其是,在BaTiO3:Eu中Eu2+的發(fā)射光譜帶隨著Eu濃度的增加而變寬。當Eu的濃度為0.5mol%時,可以觀察到5D0→7F0和5D1→7F0的發(fā)射。此外,在537nm激發(fā)下,發(fā)射強度隨Eu濃度的增加而增大。(2)Bi2MoO6:Ln3+納米晶的光致發(fā)光及光催化活性研究。通過水熱法合成了片狀的Bi2MoO6:Ln3+納米晶。Bi2MoO6:Ln3+納米晶的晶粒大小隨著在反應液中增加Ln3+的含量而變化。對Bi2MoO6:Ln3+納米晶的光致發(fā)光性能也進行了詳細的研究。在Bi2MoO6:Eu3+納米晶的發(fā)射光譜中,5D0→7F2的發(fā)射遠遠強于5D0→7F1。當激發(fā)波長為467nm時,發(fā)射強度最強。隨著Eu3+離子濃度的增加,Eu3+的發(fā)射強度也增大,一直增加到Eu3+含量為50mol%,然后下降。在618nm監(jiān)測下,Bi2MoO6:Eu3+(30%)/Gd3+的激發(fā)光譜中,當Gd3+濃度為10%或20%時,主要為7F0→5D2(467nm)的發(fā)射。當Gd3+的濃度為30%時,主要為7F0→5D1(538nm)的發(fā)射。此外,Bi2MoO6:Eu3+的光催化活性通過在可見光下降解羅丹明B的實驗來進行研究的。可以觀察到最好的光催化活性是當Eu3+濃度為1%時。
[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，

本文編號：1460740