稀土掺杂钙钛矿结构发光和光催化材料的制备与性能研究

发布时间：2018-03-25 05:34

本文选题：钙钛矿结构　切入点：发光材料　出处：《天津理工大学》2017年硕士论文

【摘要】：钙钛矿结构材料在压电、铁电、发光、催化、磁电阻等多种功能材料领域都占有重要地位,是当前材料科学领域的研究热点。本学位论文围绕稀土掺杂的具有钙钛矿结构的荧光粉材料和光催化材料的制备及相关性能的研究展开工作,探究稀土离子掺杂对钙钛矿结构材料发光性能和光催化性能的影响。主要成果如下:1.钙钛矿结构BaSiO_3:Eu~(2+)材料的制备及发光性质与光催化性能的研究。采用高温固相法和共沉淀法制备BaSiO_3:Eu~(2+)荧光粉材料,比较二者的发光性质后发现,高温固相法制得的样品为505 nm的绿光发射,而共沉淀法制备的样品为570 nm的黄光发射。通过实验辨明了Eu~(2+)在钙钛矿结构BaSiO_3基质中的本征发射为570 nm的黄光发射,而文献中报道的505 nm的绿光发射源于高温固相反应过程中生成的杂相Ba2SiO4:Eu~(2+)的发光。同时,本文还对纯钙钛矿结构BaSiO_3:Eu~(2+)材料进行了光催化性能的研究,结果显示其光催化性能较差。2.钙钛矿结构SrTiO_3:Pr~(3+)/Eu~(3+)材料的制备及发光性质的研究。采用溶胶凝胶法制备SrTiO_3:Pr~(3+)/Eu~(3+)荧光粉材料并研究其发光性质。结果表明SrTiO_3:Pr~(3+)荧光粉材料中Pr~(3+)的激发源于基质的带间吸收、Ti-O间电荷迁移跃迁和缺陷能级吸收;Eu~(3+)在SrTiO_3:Eu~(3+)荧光粉材料中的激发则来自于电荷迁移态、基质和Eu~(3+)离子之间通过非辐射交叉弛豫的过程实现有效的能量传递。3.稀土掺杂钙钛矿结构SrTiO_3材料的制备及光催化性能的探究。通过溶胶凝胶法制备了Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu元素掺杂的SrTiO_3光催化材料并对比其光催化性能,发现在相同条件下,Y~(3+)掺杂SrTiO_3材料的催化性能最佳,对光的利用率可达96%。除此之外,我们通过改变Eu~(3+)掺杂浓度、制备方法、调节反应溶液pH值及反应气氛四个方面分析其对Eu~(3+)掺杂钙钛矿结构SrTiO_3的光催化性能的影响。结果如下:实验条件相同的情况下,浓度为0.08 mol Eu~(3+)掺杂的SrTiO_3样品紫外-可见光照160 min之后对罗丹明B的降解率为70%,但采用溶胶凝胶法在反应溶液pH=5并在空气中烧结的0.02 mol Eu~(3+)掺杂SrTiO_3光催化性能更好,对RhB的降解率为92%。
[Abstract]:Perovskite structural materials play an important role in the fields of piezoelectric, ferroelectric, luminescent, catalytic, magnetoresistance and other functional materials. This dissertation focuses on the preparation and properties of rare earth doped phosphors and photocatalytic materials with perovskite structure. To explore the effect of rare earth ion doping on the photoluminescence and photocatalytic properties of perovskite structure materials. The main results are as follows: 1. Preparation, luminescence and photocatalytic properties of perovskite structure BaSiO_3:Eu~(2) materials. BaSiO_3:Eu~(2) phosphors were prepared by co-precipitation method. Comparing the luminescence properties of the two methods, it was found that the green emission of the samples obtained by high temperature solid phase method was 505 nm. However, the sample prepared by coprecipitation is yellow light emission of 570nm. The intrinsic emission of Eu~(2 in perovskite structure BaSiO_3 matrix is identified as 570nm yellow light emission. However, the green emission of 505nm reported in the literature originated from the luminescence of heterophase Ba2SiO4:Eu~(2 generated during the high temperature solid state reaction. Meanwhile, the photocatalytic properties of pure perovskite structure BaSiO_3:Eu~(2) materials were also studied. The results show that the photocatalytic properties of perovskite structure SrTiO_3:Pr~(3 / Eufon 3) are poor. The preparation and luminescence properties of perovskite structure SrTiO_3:Pr~(3 / Euf3) phosphors are studied. The SrTiO_3:Pr~(3 / EEU 3) phosphors have been prepared by sol-gel method and their luminescence properties have been studied. The results show that SrTiO_3:Pr~(3) phosphors are phosphors. The excitation of Pr~(3) in the SrTiO_3:Eu~(3) phosphors originates from the charge transfer transition between the interband absorption of Ti-O and the absorption of the defect energy levels from the charge transfer state in the SrTiO_3:Eu~(3) phosphors. The effective energy transfer between the matrix and Eu~(3 ions was achieved through the process of non-radiative cross-relaxation. 3.The preparation and photocatalytic properties of rare-earth doped perovskite structure SrTiO_3 materials were investigated. The preparation of SrTiO_3 with rare earth doped perovskite structure and its photocatalytic properties were studied by sol-gel method. The photocatalytic properties of SrTiO_3 photocatalytic materials doped with pigment were compared. It is found that the catalytic performance of the doped SrTiO_3 material is the best under the same conditions, and the utilization ratio of light can reach 96%. In addition, by changing the concentration of Eu~(3), the preparation method is obtained. The effects of the reaction solution pH value and reaction atmosphere on the photocatalytic properties of perovskite SrTiO_3 doped with Eu~(3 were analyzed. The results are as follows: under the same experimental conditions, The degradation rate of rhodamine B in the SrTiO_3 sample doped with 0.08 mol Eu~(3 was 700.The degradation rate of rhodamine B was 700.The photocatalytic activity of SrTiO_3 doped with 0.02 mol Eu~(3 sintered in the reaction solution pH=5 and in air by sol-gel method was better. The degradation rate of RhB was 92%.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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