【作者】 程丹；

【导师】 张昕彤；

【作者基本信息】 东北师范大学 ， 凝聚态物理， 2010， 硕士

【摘要】 白光LED具有低工作电压、低功耗、高流明效率和长寿命等一系列优点,是一种环保和节能的新型照明光源。因此白光LED及相关发光材料成为现在研究的热点。本文针对白光LED用长波紫光和紫外光激发的蓝色荧光材料进行研究。本文首先对白光LED用蓝色荧光粉的研究现状、发展趋势以及各种制备方法进行了详细的综述。从高显色性白光LED需求的角度选择（SrCaBa）₃（PO₄）₂·SrCl₂:Eu²⁺蓝色荧光粉为研究对象。采用高温固相法在弱还原气氛中成功制备（SrCaBa）₃（PO₄）₂·SrCl₂:Eu²⁺蓝色荧光粉。详细研究了反应原料、烧结温度、Eu²⁺激活剂浓度对荧光粉发光性质的影响。研究表明温度在1200℃,Eu²⁺掺杂比为0.15时（SrCaBa）₃（PO₄）₂·SrCl₂:Eu²⁺蓝色荧光粉的发光峰在450nm并且可被200nm- 440nm波段有效激发。进一步基于Eu²⁺与Tb³⁺之间的能量传递设计制备（SrCaBa）₃（PO₄）₂·SrCl₂:Eu³⁺,Tb³⁺荧光粉。样品在长波紫光和紫外光激发下呈蓝光与绿光的混合发光,发光颜色随Tb3+掺杂浓度可从蓝色调节为蓝绿色,从而可进一步提高白光LED的显色性。本文对高显色性白光LED用发光材料的研制有重要意义。更多还原

【Abstract】 White light-emitting diode （W-LED）, as a novel kind of‘green lighting’, has many advantages over incadescent and fluorescent lamps, such as low working voltage, low power consumption, high luminous efficiency and long life. Therefore, W-LED and related phosphors have attracted worldwide attention. In this Master Thesis, we focus our research on blue-emitting phosphors that can be excited by long-wave ultraviolet or violet LED chips and will have practical applications in W-LED.We review in the first part of thesis the present situation and future trends of W-LED and blue-emitting phosphors, with emphasis placed on the mechanism of W-LED, various kinds of phosphors and various preparation methods. For the demand of high color rendering W-LED, we chose （SrCaBa）₃（PO₄）₂·SrCl₂:Eu²⁺ blue-emitting phosphor powder as the object of our study, and use high-temperature solid-state reaction method to prepare the phosphor powders in a weak reducing atmosphere. A detailed investigation on the reaction parameters, including kinds and relative ratio of raw materials, sintering temperature and Eu²⁺ activator concentration was conducted in terms of luminescent properties of phosphors powder. Our study show that optimal reaction parameters are: sintering temperature is 1200℃, Eu²⁺ doping level is 0.15. By these parameters, the （SrCaBa）₃（PO₄）₂·SrCl₂:Eu²⁺ phosphor powder show bright blue emission around 450nm and can be efficiently excited by violet and ultraviolet light （200nm- 440nm）.Further we employed the energy transfer between Tb³⁺ and Eu²⁺ and prepared a novel series of phosphors using （SrCaBa）₃（PO₄）₂·SrCl₂ as host material. Our study show that emission color can be adjusted from blue to blue green by the ratio of Tb³⁺ to Eu²⁺, with line-like Tb³⁺ green emission overlapped on band-like Eu²⁺ blue emission. This novel series of phosphors may have promising applications in high-color-rendering W-LED.更多还原