低温燃烧法制备白光LED铝酸盐荧光粉发光性能研究

发布时间：2018-08-27 19:25

【摘要】：发光二极管(light emitting diode,LED)作为一种新型固体光源,以其节能、绿色环保、寿命长且体积小等诸多优点,在室内照明、液晶显示以及背光源等方面显示出巨大的应用前景。获取白光LED的途径大致有三种:光转换、多色LED芯片组合和多量子阱。光转换法是目前较常用的方法,然而传统YAG:Ce3+荧光粉由于显色性低、色温高等因素制约而难以满足发展需求,因此利用近紫外芯片激发三基色荧光粉成为获得白光LED具有发展潜力的途径,因而发展高性能三基色荧光粉具有重要意义。目前合成荧光粉的主要方法是高温固相法,但此种方法存在生产周期长、合成材料需要的温度高、时间长、产物结块严重等缺点,在这种情况下就需要一种更为优良的荧光粉制备方法。燃烧法与高温固相法相比,原料混合均匀后为非固体粉末形态,这比高温固相法中的球磨原料混合固态粉体的方法更均匀,每种成份控制也更为准确,具有容易、快捷的特点,因此在各种氧化物的合成中广泛应用。该技术是利用氧化剂和还原剂之间在低温下点燃,继而发生氧化还原反应放出的热量的原理。此外,这种合成方法具有节能、高效、和安全性高的优点,而且产物具有良好的结晶度及发光强度。因而低温燃烧法制备铝酸盐荧光粉对研究对白光LED的发展具有深远的影响。铝酸盐基质荧光粉具有较高的量子效率,良好的热稳定性和化学稳定性引起了人们的广泛研究。本文利用低温燃烧法制备了铝酸盐荧光粉并对其结构和发光性能进行了系统的表征分析,研究方法及结论如下。首先,利用低温燃烧法制备了铝酸盐基发光材料Sr Mg A110O17:Eu2+,通过改变尿素用量、硼酸用量、初始炉温和激活剂含量等,研究不同合成条件对样品的发光性能的影响。并通过XRD图分析结构表明,燃烧法可合成单一相位的Sr Mg A110O17结构;光谱分析结果表明:Sr Mg Al10O17:Eu2+荧光粉可被近紫外LED芯片有效的激发,其发射光谱分布在430~520nm之间,发射峰位于460nm,是蓝光荧光粉的一种。其次,为了进一步提高MMg A110O17:Eu2+的发光强度,在MMg A110O17:Eu2+中共掺杂Er3+制备出MMg A110O17:Eu2+,Er3+荧光粉,对所得样品进行表征分析,总结Er3+的掺杂浓度对产物发光性能的影响,并解释荧光粉浓度猝灭的原理及Er3+对Eu2+的敏化作用机理。最后,为了进一步扩大荧光粉发射光谱的范围,用同样的方法制备MMg A110O17:Eu2+,Mn2+(M=Ca,Sr,Ba)荧光粉,对其结构形貌和荧光性质进行了研究,并且在现有机理基础上深入讨论了荧光粉中能量传递的机理,解释Mn2+离子的掺杂对荧光粉发光性能的影响。本文的研究为荧光粉的制备采用了一种较新的方法—低温燃烧法,并通过工艺的优化提高荧光粉的发光性能,然后通过优化了的工艺制备出Sr Mg A110O17:Eu2+,Er3+高亮度荧光粉和Sr Mg A110O17:Eu2+,Mn2+光谱可调荧光粉。关键词:燃烧法;铝酸盐荧光粉;白光LED;能量传递
[Abstract]:As a new kind of solid light source, (light emitting diode,LED (Light emitting Diode) has shown great application prospect in indoor lighting, liquid crystal display and backlight, because of its advantages of energy saving, environmental protection, long life and small volume. There are three ways to obtain white LED: optical conversion, polychromatic LED chip combination and multiple quantum wells. Optical conversion is a common method at present. However, the traditional YAG:Ce3 phosphors are difficult to meet the development needs because of their low color rendering, high color temperature and other factors. Therefore, the use of near-ultraviolet chips to excite tricolor phosphors is a promising way to obtain white LED, so it is of great significance to develop high performance tricolor phosphors. At present, the main method of synthesizing phosphors is high temperature solid phase method, but this method has many disadvantages, such as long production cycle, high temperature, long time required for synthesizing materials, serious caking of products, etc. In this case, a better preparation method of phosphors is needed. Compared with the high temperature solid state method, the combustion method is more uniform than the ball milling method in the high temperature solid state method, and the control of each component is more accurate, which has the characteristics of easy and quick. Therefore, it is widely used in the synthesis of various oxides. This technique is based on the principle of redox reaction between oxidant and reducing agent igniting at low temperature. In addition, this method has the advantages of energy saving, high efficiency and high safety, and the product has good crystallinity and luminescence intensity. Therefore, the preparation of aluminate phosphors by low temperature combustion has a profound influence on the development of white LED. Aluminate matrix phosphors have been widely studied because of their high quantum efficiency, good thermal stability and chemical stability. In this paper, aluminate phosphors were prepared by low temperature combustion method, and their structure and luminescent properties were systematically characterized and analyzed. The research methods and conclusions are as follows. Firstly, the aluminate based luminescent material Sr Mg A110O17:Eu2 was prepared by low temperature combustion. By changing the amount of urea, the amount of boric acid, the initial furnace temperature and the content of activator, the effects of different synthesis conditions on the luminescent properties of the samples were studied. The structure analysis of XRD diagram shows that the single phase Sr Mg A110O17 structure can be synthesized by combustion method, and the spectral analysis results show that the Mg Al10O17:Eu2 phosphor can be effectively excited by the near ultraviolet LED chip, and its emission spectrum is distributed in the range of 430~520nm. The emission peak is located at 460 nm and is one of the blue phosphors. Secondly, in order to further improve the luminescence intensity of MMg A110O17:Eu2, MMg A110O17:Eu2 er _ 3 phosphors were prepared by co-doped Er3 with MMg A110O17:Eu2. The samples were characterized and analyzed, and the effects of Er3 doping concentration on the luminescence properties of the products were summarized. The mechanism of concentration quenching of phosphors and the sensitization mechanism of Er3 to Eu2 were explained. Finally, in order to further expand the range of phosphor emission spectrum, MMg A110O17:Eu2 _ (mn _ 2) phosphors were prepared by the same method. The structure, morphology and fluorescence properties of the phosphors were studied. On the basis of the existing mechanism, the mechanism of energy transfer in phosphors is discussed in depth, and the influence of doping of Mn2 ions on the luminescent properties of phosphors is explained. In this paper, a new method of low temperature combustion is adopted for the preparation of phosphors, and the luminescent properties of phosphors are improved by optimizing the process. Then the Sr Mg A110O17:Eu2 er 3 phosphors and the Sr Mg A110O17:Eu2 MNO 2 phosphors were prepared by the optimized technology. Keywords: combustion method; aluminate phosphor; White LED; energy transfe
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8

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