【作者】 冯章雷；

【导师】 石建新；

【作者基本信息】 中山大学 ， 无机化学， 2010， 硕士

【摘要】 自1996年,第一支白光LED问世后,由于其寿命长、节能、绿色环保照明等显著优点被喻为新一代照明光源。但由于目前应用于 400 nm近紫外-紫外芯片上的三基色荧光粉主要还是传统的荧光粉,这些传统的荧光粉在近紫外区激发的光效不高,并且其中的绿色荧光粉和红色荧光粉均为硫化物,稳定性差,在制备和使用过程中容易对环境造成污染,使得白光LED发光效率和使用寿命不易提高。因此,研究新型的InGaN-LED用荧光粉具有重要的学术意义和实际应用前景。本学位论文就是寻找适合近紫外InGaN基荧光转换型LED用的新型、高效、稳定的荧光粉,分别研究了能适合于近紫外InGaN基荧光转换型白光LED用的稀土离子Eu（Ⅱ/Ⅲ）掺杂的无机荧光粉,并利用XRD(X-射线衍射对其结构进行表征,详细研究其光致发光性能,最后,筛选出荧光性能较好的化合物与近紫外InGaN芯片结合,制成LED,探讨其发光性能。本学位论文共分6章撰写。第1章首先介绍白光二极管的发展历程,综述了当前白光LED用荧光粉的研究现状并简述了稀土发光材料的研究进展。最后阐述了本学位论文的选题依据以及研究内容。第2章采用高温固相法制备了Eu³⁺离子掺杂系列Y_1-xEu_x（PO₃）₃ （0≤x≤1）红色荧光粉,采用XRD和荧光光谱对其结构及荧光性质进行了表征。结果表明在600℃ 900℃温度范围内,均可得到单一的Y（PO₃）₃、Eu（PO₃）₃纯相,我们选择800℃条件下焙烧所得的样品,详细的研究其光致发光性能,结果得出当x = 1时其发光最强。第3章采用高温固相法制备了Eu³⁺离子掺杂BaCa_1-x（PO₃）₄:xEu³⁺系列荧光粉,并在对其合成和表征的基础上进行了Li+离子离子共掺杂的研究工作,制备系列BaCa_0.9-xEu_0.1Li_x（PO₃）₄红色荧光粉,并用XRD和荧光光谱对其结构及荧光性质进行了表征。结果显示,在得到纯相的前提下,BaCa_1-x（PO₃）₄:xEu³⁺荧光粉中Eu³⁺掺杂含量为0.10时发光强度最高,当Li⁺掺杂浓度为0.15时,荧光粉BaCa0.75Eu0.1Li0.15（PO₃）₄的发光强度最高,并且通过Li⁺的共掺杂,在补偿电荷的同时,也增强了荧光粉的发光强度。第4章采用CO弱还原气氛高温固相法制备了Eu²⁺、Mn²⁺掺杂系列Ba_1-xEuxCa （PO₃）₄,Ba_0.85Eu₉0.15)Ca_1-xMn_x（PO₃）₄荧光粉,并研究了其光致发光性质。结果表明,掺杂Eu²⁺的Ba_1-xEu_xCa （PO₃）₄的荧光粉为纯相的前提下,在此体系中随着Eu²⁺离子掺杂浓度的增加,发光强度也在增加,当掺杂浓度为0.15时最强,激发光谱没有明显的改变。在Ba_0.85Eu_0.15Ca_1-xMn_x（PO₃）₄体系中,随着Mn²⁺离子浓度的增加,发生了能量的传递。第5章研究了所制备的荧光粉在近紫外InGaN基白光LED中的应用。将制备所得到的性能较好的单色荧光粉Eu（PO₃）₃ , BaCa_0.9（PO₃）₄:0.1Eu³⁺ ,BaCa_0.75Eu_0.1Li_0.15（PO₃）₄分别于³95 nm芯片结合制作红光LED。第6章总结了本学位论文的主要工作,并根据工作的进展和存在的不足,对今后近紫外光激发光转换型LED用的稀土荧光粉的研究作了简要的展望。更多还原

【Abstract】 Since the first white-light emitting diode （WLED） came into being in 1996, more and more interests have been focused on them because they have a lot of advantages on long lifetime, lower consumption, and eco-friendly etc. However, the current tri-color phosphors for NUV LEDs are mainly some traditional phosphors. These phosphors show lower excitation efficiency in NUV region. Furthermore, the green and red phosphors show low stabilities and cause some environmental problems both in preparation and in LED application as they contain sulfur element, which would release toxic sulfur oxides in use. All the above reasons cause the difficulties to improve luminescence efficiency and operation lifetime of white LEDs. Hence it is academic interesting and shows application potential to improve traditional phosphors or search for new phosphors applied in near UV LEDs. The purpose of this thesis is to search for novel phosphors which have high luminescence efficiency and stability for NUV LEDs. To overcome the defects and shortages of the currently used phosphors, Eu（Ⅱ/Ⅲ） doped complex oxides were synthesized in the NUV WLEDs in this thesis. The structure and morphology of the phosphors were characterized by X-ray diffraction（XRD）, their photoluminescent properties were investigated. Finally, LEDs were fabricated by coating the chosen phosphors onto the NUV-emitting InGaN chips. The thesis consists of the following six chapters.In the first chapter, the development of WLEDs illumination was briefly introduced. The development of white LEDs and the current phosphors for near UV LEDs were reviewed. At last, the research subject and content of thesis were designed.In the second chapter, a series of Eu³⁺ doped Y_1-xEux（PO₃）₃ （0≤x≤1） phosphors were prepared by solid state reactions. The XRD and photo-luminescent properties of the phosphors were investigated. The results show that, the obtained phosphors were pure-phase when the sample Y_1-xEux（PO₃）₃ calcinated at the temperature range between 600 and 900℃, then we studied the photoluminescent properties of the samples calcinated at 800℃in detail, and the samples have a best photoluminescent properties can be obtained when x=1.In the third chapter,a series of Eu³⁺ doped BaCa_1-x（PO₃）₄:xEu³⁺ phosphors were prepared by solid state reactions, a series of Li+ and Eu³⁺ codoped BaCa（PO₃）₄ were prepared in the following time. The XRD and photo-luminescent properties of the phosphors were investigated. The results show that, the emission intensity of BaCa_0.9（PO₃）₄:0.1Eu³⁺ among the BaCa_1-x（PO₃）₄:xEu³⁺ is the highest, the photo-luminescence intensity of BaCa_0.75Eu_0.1Li_0.15（PO₃）₄ is the highest in BaCa_0.9-xEu_0.1Li_x（PO₃）₄ , the results show that the photo-luminescence can be enhanced by doping Li⁺ ions. Furthermore, the test results of BaCa_0.9-xEu_0.1Li_x（PO₃）₄ phosphors show that the doping of Li+ ions under some concentration can obviously enhance the photo-luminescence intensity, with the compensation for charge.In the fourth chapter, a series of phosphors Ba_1-xEu_xCa（PO₃）₄ ,Ba_0.85Eu_0.15Ca_1-xMnx（PO₃）₄ were prepared in CO ambience at 700℃and their photoluminescent properties were studied. With the increase of the doped Eu²⁺ concentration, the resultsindicate that the excitation spectra of the phosphors have no obvious change, but the photoluminescent intensity continually enhanced. It began to decreased when x=0.15. With the increase in Mn²⁺, energy transfer can be observed in Ba0.85Eu0.15Ca_1-xMnx（PO₃）₄. In the fifth chapter, in order to investigate the application of the synthesized phosphors in NUV-InGaN-based white LED, red LEDs were fabricated by coating the phosphors Eu（PO₃）₃ , BaCa_0.9（PO₃）₄:0.1Eu³⁺ , BaCa_0.75Eu_0.1Li_0.15（PO₃）₄ onto the NUV-emitting InGaN chips.,In the last of this thesis, the main research results were summarized and a brief prospect on the phosphors applied in NUV InGaN-based LED was made.更多还原