【作者】 薄素玲；

【导师】 王喜贵；

【作者基本信息】 内蒙古师范大学 ， 光学， 2009， 硕士

【摘要】 本论文首先采用共沉淀法和高温焙烧法制备了CaMoO₄:RE (RE=Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)。通过TG-DTA分析的测试发现,CaMoO₄:RE(RE =Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)样品材料分别在800℃(CaMoO₄:Eu³⁺)、850℃(CaMoO₄:Tb³⁺)和866℃(CaMoO₄:Eu³⁺:Tb³⁺)达到最高的活化点,使CaMoO₄:RE(RE=Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)样品形成稳定结构;XRD的测试结果表明样品在800℃(CaMoO₄:Eu³⁺)、850℃(CaMoO₄:Tb³⁺)和866℃(CaMoO₄:Eu³⁺:Tb³⁺)时,形成了四方晶形结构,具有与白钨矿CaMoO₄相同的结构,这也进一步说明在样品中2个M取代3个Ca²⁺,导致了晶体产生微小的晶体缺陷,从而形成具有p-n结的半导体,并且当样品受激时,晶体中的电子与空穴会相遇形成电子-空穴的束缚态,即F-激子。通过三维荧光谱图,激发和发射谱图的测试结果证明:这种缺陷结构不但可以使M禁戒的4f电子发生跃迁,而且还可以使MoO₄^2-的能量高效地传递给M,尤其是与MoO₄^2-的发射特征峰（488nm）产生部分或完全重叠的M的4f电子跃迁。进而CaMoO₄:Eu³⁺在λex=465nm的发射谱图中,自激活荧光体MoO₄^2-的发射强度被大大减弱甚至猝灭,而Eu³⁺的5D0—7F2（612nm）跃迁的红光发光强度被大大增强;同样CaMoO₄:Tb³⁺在λex=488nm的发射谱图,随着自激活荧光体MoO₄^2-的发射强度猝灭,Tb³⁺的⁵D₄→⁷F₅（544nm）磁偶级跃迁的绿光强度得到了很大的加强;而对于样品CaMoO₄:Eu³⁺:Tb³⁺在λex=302nm的发射谱图中,可以同时发出蓝、绿和红光。由于上述CaMoO₄:RE材料具有各自的明显特征,很有可能成为具有潜在应用价值的发光材料。文中还采用溶胶-凝胶法制备了RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)以CaMoO₄和SiO₂为基质发光材料。通过XRD谱图表明:样品主要形成的是非晶态SiO₂结构,但在网格中还存在CaMoO₄:RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)的小晶体,并且在小晶体的内部仍然具有由于RE取代造成的缺陷,进而产生的p-n结和受激时产生的F-激子。通过三维荧光谱图、激发和发射谱图测试表明:在SiO₂网格中的CaMoO₄:RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)小晶体仍然具有晶体的所有特性,但是CaMoO₄:RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)小晶体毕竟处于SiO₂网格中,使得MoO₄^2-只能向RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)传递部分能量,另一部分能量就用于自身荧光体MoO₄^2-发光。如:SiO₂:CaMoO₄:Eu³⁺在λex=465nm的发射谱图中,既有MoO₄^2-在498nm和514nm处的绿光发射,也有Eu³⁺在612nm处的红光发射;SiO₂:CaMoO₄:Tb³⁺在λex=488nm的发射谱图中,有MoO₄^2-在517nm和Tb³⁺在544nm的两处绿光发射;而对于样品材料SiO₂:CaMoO₄:Tb³⁺:Eu³⁺则在λex=302nm的发射谱图中,可以发射出蓝、绿和红光,并且三种颜色的光强度基本相同。因此,制备的SiO₂:CaMoO₄:RE(Eu³⁺,Tb³⁺或Eu³⁺和Tb³⁺共掺)材料可以在同一种材料中同时发出一种、两种或者三种颜色的光。更多还原

【Abstract】 In this paper, first of all, the sample CaMoO₄:RE(RE= Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺) has been prepared with the coprecipitation method and high-temperature roasting method. TG-DTA spectra shows that the energy of the samples is up to the maximum implying that it has formed stable structures at 800℃(CaMoO₄:Eu³⁺),850℃(CaMoO₄:Tb³⁺) and 866℃(CaMoO₄:Eu³⁺:Tb³⁺) respectively. XRD pattern of the sample shows that the CaMoO₄:Eu³⁺ （800℃）、CaMoO₄:Tb³⁺ （850℃）and CaMoO₄:Eu³⁺:Tb³⁺ （866℃）, at the single phase, is a representative scheelite structure of CaMoO₄.Due to three Ca²⁺ replaced by two RE in the cell of the samples CaMoO₄:RE(RE= Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺), the crystal produced tiny crystal defect, so that it has the samples CaMoO₄:RE (RE=Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺) form the semiconductor which is possessed of p-n junctions, as the samples are waken, the hole and the electron around the hole, it can form a F- （Frenkel） exciton, which is at the bound state, in the crystal.The three-dimensional fluorescence spectra, excitation and emission spectras of the samples are investigated and reveal that the defect structures of the sample not only enable the but also make energy of MoO₄^2- high efficiently transfer RE, especially the 4f electron of the RE transit, with the 488 nm of MoO₄^2- partly or completely overlapped, is greatly strengthened. For the sample CaMoO₄:Eu³⁺, as a result, the emission spectra withλex=465nm shows the emission intensity of the spontaneously activated fluorescence MoO₄^2- is greatly weaken or even quenching, while the red light luminescence intensity of the 5D0-7F2 transition（612nm）of Eu³⁺ is greatly enhanced, similarly the emission spectra of CaMoO₄:Tb³⁺ withλex=488nm shows the emission intensity of the green light luminescence intensity of the ⁵D₄→⁷F₅ transition （544nm）of the Tb³⁺ is greatly enhanced. About the emission spectra of the sample CaMoO₄:Eu³⁺:Tb³⁺ withλex=302nm, it can emit blue、green and red light at the same time. These particular advantages tell us a fact that the samples CaMoO₄:RE(RE= Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺) will become the luminescence material that is of great potentially used value.In addition, the sample RE(RE=Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺) to CaMoO₄ and SiO₂ matrix light-emitting materials, it are prepared by the sol-gel method. XRD spectra of the sample show that the samples are mainly formed by the structure of amorphous SiO₂, but the small crystals of CaMoO₄:RE (RE=Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺),which are in SiO₂ network structure , and in a small crystal the defective internal still have caused RE to replace Ca²⁺, thus as a result of generating p-n junction and F-（Frenkel） exciton. Through three-dimensional fluorescence spectra, excitation and emission spectra of the sample showed that: CaMoO₄:RE(RE=Eu³⁺, Tb³⁺ or co-doped Eu³⁺ and Tb³⁺) still has all the character of a small crystal,but after all in SiO₂ network structure, it make transfer part of the energy from MoO₄^2- to the RE (RE=Eu³⁺ , Tb³⁺ or co-doped Eu³⁺ and Tb³⁺), the other part of energy is saved for its own emitting phosphor of MoO₄^2-. Such as the emission spectrum of the sample SiO₂:CaMoO₄:Eu³⁺ atλex= 465nm, it takes on green light of MoO₄^2-in 498nm and 514nm and red light of Eu³⁺ in 612nm; the emission spectrum of SiO₂:CaMoO₄:Tb³⁺ inλex= 488nm, it presents two green light of MoO₄^2- in the 517nm and Tb³⁺ in the 544nm; the emission spectra of sample materials for SiO₂:CaMoO₄:Eu³⁺:Tb³⁺inλex= 302nm, it emits blue, green and red light at the same time, and the intensity is basically the same of three colors. Therefore, it can take on one, two or three colors of light in the same material SiO₂:CaMoO₄:RE(RE=Eu³⁺, Tb³⁺ or co-doped Eu³⁺and Tb³⁺).更多还原