【作者】 刘涛；

【导师】 李永绣；

【作者基本信息】 南昌大学 ， 无机化学， 2011， 硕士

【摘要】 白光LED具有发光效率高、寿命长、节能无污染等优点,因而越来越受到人们的重视。目前最成熟的白光LED的制备技术为荧光粉涂覆的光转换法,其中荧光粉对白光LED性能起着非常重要的作用。因此探求新型的可被紫外光或蓝光芯片激发的荧光粉成为目前白光LED研究工作的热点。白光LED的光效、色度参数和价格是其最为重要的指标,而这些指标是由LED芯片以及涂覆在芯片上的荧光转换材料决定的。本研究选择Gd2(Mo04)3：Eu3+和ZnMoO4:Eu3+两类荧光粉为研究对象,通过掺杂等来提高该类荧光粉的发光强度及降低粉体成本,致力于合成一些可被蓝光或近紫外光有效激发的新型荧光粉,使其适用于商用LED芯片。Gd2-x(MoO4)3:xEu3+(x=1.0)是一种可被近紫外(395 nm)和蓝光(466 nm)有效激发的高效红色荧光粉。结果表明：该系列荧光粉的最佳合成温度为950℃；通过P043-和碱金属离子掺杂均可显著提高该体系荧光粉发光强度,确定了合成荧光粉的最佳组成为GdEu(MoO4)2.85(PO4)0.10、GdEu(MoO4)2.8(PO4)0.2Li0.2和GdEu(MoO4)2.8(PO4)0.2Na0.2,它们在395 nm光激发时的发光强度分别在Gd(MoO4)3:Eu3+的基础上提高了1.36倍、1.69倍和1.57倍。Li0.5Gd0.5-xMoO4:Eu3+x荧光粉中最佳Eu掺杂浓度x为0.125；与Na0.5Gd0.375MoO4：Eu3+0.125对比,在相同最大激发波长下,前者的最大发光强度为后者的1.30倍；同时发现P043-掺杂对钼酸钙体系荧光粉的荧光强度增强也有不错效果。Zno.454M004：Eu0.25Li0.25Bi0.04Sm0.006荧光粉的最佳合成温度为750℃,保温时间为6 h。本文获得了Zno.5Li0.25Mo097O4：Eu3+0.25Si0.03荧光粉,相对荧光强度是未掺杂硅的1.416倍。首次发现Pr3+单掺杂ZnMoO4可以被蓝光(450 nm)有效激发,形成红光(主峰643 nm窄带)发射,是一种新型可被蓝光LED有效激发的红色荧光粉。Dy3+单掺杂ZnMoO4在紫外354 nm可以有效激发,形成黄光(577nm窄带)发射,是一种新型可用于紫外LED芯片的黄色荧光粉。更多还原

【Abstract】 White LEDs with high luminous efficiency, long life, energy saving and green have attracted more and more attention. Currently, the most mature technology for the preparation of white LED is light conversion method of phosphor coating. Therefore, phosphors with high efficiency and stability under excitation of ultraviolet light or blue become the research hotspot of white LED. The parameters of luminescent efficiency, chromaticity parameters and the price of LEDs are the most important indicators which are determined by the LED chips and the conversion material coated on. In this study, We selected Gd2(MoO4)3:Eu3+ and ZnMoO4:Eu3+ phosphors as research objects for improving the emission intensity by co-doping with some other cheap elements for the purpose of reducing cost.Gd2-x(MoO4)3:xEu3+(x=1.0) phosphors emit red fluorescence under excitation of near ultraviolet (395 nm) and blue (466 nm). Their optimum synthesis temperature was found to be 950℃and their luminous intensity can significantly be improved by the doping of PO43- and alkali metal. The emission intensities of phosphors Gd2-x(MoO4)3:xEu3+(x=1.0), GdEu(MoO4)2.85(P04)0.10,GdEu(Mo04)2.8(PO4)0.2Li0.2 and GdEu(MoO4)2.8(PO4)0.2Na0.2 under excitation of 395 nm are 1.36 times,1.69 times and 1.57 times than that of Gd(MoO4)3:Eu3+ respectively. On the other hand, phosphor Li0.5Gd0.5-xMoO4:Eu3+x with x=0.125 shows stronger luminescence emission than Na0.5Gd0.375MoO4:Eu0.1253+. Meanwhile, the fluorescence intensity of phosphors of calcium molybdate systems can also be enhanced by phosphate doping.At the same time, we determined that the optimum calcination condition of Zn0.454MoO4:Eu0.25Li0.25Bi0.04Sm0.006 is at 750℃for 6h, and the fluorescence intensity of Zn0.5Li0.25Mo0.97O4:Eu3+0.25Si0.03 is 1.416 times as high as that of phosphor without doping of silicon. We also synthesized ZnMoO4-based phosphors of single-doped with Pr3+ or Dy3+, the former one emits red ligh at 643nm by 450nm excitation, and the later one emits yellow light at 577 nm by 354 nm.更多还原