紫外、近紫外白光LED用铝酸盐、硅酸盐发光材料的制备及发光性能研究

发布时间：2018-09-14 10:37

【摘要】：近年来,发光二极管(LED)凭借其高亮度、高显色指数、低能耗、长寿命、环境友好等优点,日益成为最有潜质的照明光源。因此,用于LED的紫外,近紫外发光材料的基础研究也得到了越来越多的关注。一般来说,近紫外LED用荧光粉需要在近紫外区有较高的吸收效率,以及较高的能量转换率。此外,荧光粉还应具有较高的热稳定性,以承受LED芯片工作时所产生的热量。因此用于白光LED的铝酸盐,硅酸盐荧光粉凭借其转换效率高,化学稳定性好等优点脱颖而出。随着紫外、近紫外芯片的快速发展,红、绿、蓝三基色荧光粉与紫外、近紫外芯片匹配实现白光发射己极为普遍。然而在此三基色体系中,蓝色荧光粉由于被红色、绿色荧光粉重吸收而造成蓝光部分不足,故越来越多的人们开始寻找单一基质实现白光发射的荧光粉。比如通过Ce3+,Mn2+离子间的能量传递作用,即有可能实现单一基质白光发射。基于以上理由,我们设计并制备了紫外、近紫外波段激发的铝酸盐、硅酸盐发光材料,并研究了相应的发光性能。主要内容及结果如下：1.通过高温固相法制备了SrAl2O4:Eu2+,M1.5Y1.5Al3.5Si1.5O12:Ce3+(M=Mg2+, Ca2+, Sr2+, Ba2+),及LaA103:Eu3+等铝酸盐荧光粉,探究了这三种铝酸盐荧光粉的荧光特性。实验发现,通过掺杂Ba2+离子、Li+离子,能够有效的提高SrAl2O4:Eu2+的荧光性能；(M= Mg2+, Ca2+, Sr2+, Ba2+)系列荧光粉可被蓝光有效激发,由于所掺杂阳离子不同,蓝光激发下Mg1.5y1.5Al3.5Si1.5O12:Ce3+呈现绿光发射,而Ba1.5Y1.5Al3.5Si1.5O12:Ce3+呈现黄光发射；钙钛矿结构荧光粉LaA103:Eu3+,在紫外激发下(328 nm)有强烈的红光发射。2.通过高温固相法分别制备了Ba1.1Sr0.7SiO4:0.2Eu2+、NaYSiO4:Eu3+、NaYSiO4:Ce3+、 KLaSiO4:Eu3+、KLaSiO4:Ce3+、KLaSiO4:Ce3+,Mn2+等硅酸盐荧光粉,并探究了这6种硅酸盐荧光粉的荧光特性。实验发现,随着保温时间的延长,Ba1.1Sr0.7SiO4:0.2Eu2+的荧光特性呈下降趋势,掺杂Sb3+离子后,由于Sb3+、Eu2+离子间的能量传递作用,样品的荧光特性明显提高；NaYSiO4:Eu3+/KLaSiO4:Eu3+与NaYSiO4:Ce3+/KLaSiO4:Ce3+在紫外激发下,分别呈现红光、蓝光发射,而KLaSiO4:Ce3+,Mn2+中Ce3+?Mn2+间存在偶极-多级的能量传递作用,通过有效的能量传递,使荧光粉实现从蓝光到橘黄光颜色的转变,在最佳配比下(KLa0.96SiO4:0.02Ce3+,0.02Mn2+)实现了单一基质白光发射。
[Abstract]:In recent years, light-emitting diodes (LEDs) have increasingly become the most potential lighting source because of their high brightness, high color rendering index, low energy consumption, long life, environment-friendly and other advantages. Therefore, the basic research of ultraviolet and near-ultraviolet luminescent materials for LEDs has attracted more and more attention. In addition, the phosphor should have high thermal stability to withstand the heat generated when the LED chip works. Therefore, aluminates used in white LED, Silicate Phosphors with its high conversion efficiency, good chemical stability and other advantages stand out. With the ultraviolet, near-ultraviolet core. With the rapid development of wafers, it is very common to match red, green, blue phosphors with ultraviolet and near ultraviolet chips to achieve white light emission. However, in this three-color system, the blue phosphor is not enough because it is re-absorbed by red and green phosphors, so more and more people begin to look for a single substrate to achieve white light emission fluorescence. Based on the above reasons, we have designed and prepared luminescent materials of aluminate and silicate excited by ultraviolet and near ultraviolet bands, and studied the corresponding luminescent properties. The main contents and results are as follows: 1. Aluminate phosphors SrAl2O4:Eu2+, M1.5Y1.5Al3.5Si1.5O12:Ce3+ (M=Mg2+, Ca2+, Sr2+, Ba2+), and LaA103:Eu3+ were prepared, and the fluorescence characteristics of these phosphors were investigated. It was found that the fluorescence properties of SrAl2O4:Eu2+ could be effectively improved by doping Ba2+ and Li+ ions, and (M=Mg2+, Ca2+, Sr2+, Ba2+, Ba2+) phosphors were prepared. Due to the different doped cations, Mg1.5y1.5Al3.5Si1.5O12:Ce3+ exhibits green emission under blue excitation, while Ba1.5Y1.5Al3.5Si1.5O12:Ce3+ exhibits yellow emission; Perovskite phosphor LaA103:Eu3+ exhibits strong red emission under ultraviolet excitation (328 nm). Silicate phosphors, such as r0.7SiO4:0.2Eu2+, NaYSiO4:Eu3+, NaYSiO4:Ce3+, KLaSiO4:Eu3+, KLaSiO4:Ce3+, KLaSiO4:Ce3+, Mn2+, have been studied and their fluorescence characteristics have been investigated. The results show that the fluorescence characteristics of Ba1.1Sr0.7SiO4:0.2Eu2+ decrease with the increase of holding time. After doping Sb3+ ions, the fluorescence properties of Ba1.1Sr0.7SiO4:0.2Eu2+ have been investigated. The fluorescence properties of the samples were obviously improved by the energy transfer between the two ions, NaYSiO4:Eu3+/KLaSiO4:Eu3+/KLaSiO4:Ce3+/KLaSiO4:Ce3+ and NaYSiO4:Ce3+/KLaSiO4:Ce3+ exhibited red and blue light emission respectively under ultraviolet excitation, while there was a dipole-multistage energy transfer between Ce3+?Mn2+ in KLaSiO4:Ce3+, Mn2+, which enabled the phosphors to realize the transition from blue light to blue light through effective energy transfer. The color change of orange light was achieved under the optimum ratio (KLa 0.96SiO 4:0.02Ce 3+, 0.02Mn 2+).
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O482.31;TN312.8

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