【作者】 唐家业；

【导师】 徐鑫；

【作者基本信息】 中国科学技术大学 ， 材料学， 2013， 博士

【摘要】 随着能源危机以及环境污染的日益严重,作为能源消耗大户的照明显示领域引起了人们的关注和新一轮的研究热潮。发展新型绿色节能照明显示技术是解决这一难题的重要手段,近几十年来,以发光二极管(Light emitting diodes, LED)和等离子平板显示器(Plasmon Display Panels, PDP)为代表的照明显示技术取得了突破性的发展。相比于传统技术,LED具有体积小、发热少、耗能低、工作时间长、显色性能优异等特点；而PDP则具备体积小、重量轻、亮度高、色彩还原性好、灰度丰富等优点,将成为未来大屏幕和3D技术的主流技术。因此,综合能源、环境和成本等因素的考虑,新型照明显示技术将成为这一领域内的主流技术。光转换材料作为照明和显示技术领域中的重要组成部分,对照明显示技术的显色性和色彩丰富度起到了重要的贡献。新技术的发展对于材料提出了更高的要求,如LED和PDP均要求荧光材料具有快速响应时间,从真空紫外到近紫外波段的宽带激发,长波发射,在长期的大电流、高电压的轰击下保持化学和热稳定性,以及高量子效率等特点。传统的荧光粉存在激发光谱窄,热稳定性差等缺点,无法作为LED或者PDP荧光粉直接使用。因此,需进一步开发出与之相匹配的新型荧光转换材料。硅基氧氮化物材料具有强度高、耐腐蚀、耐高温、耐氧化等优良性能,自发现之日起就被普遍认为是最佳的荧光粉基质材料。目前的主要研究方向是硅基氧氮化物的制备技术和发光特性。本文的工作重点即围绕这个中心,具体包括：研究和探索稀土激活的硅基氧氮化物的理论计算,希望能够发现出氧氮化物发光与结构的内在因素,为氧氮化物荧光粉的设计和发展提供一定的理论和实验参考；通过合成工艺改进和形貌控制,寻找到新型荧光粉的设计方向,优化氧氮化物荧光粉粉体形貌和粒径分布,本论文分为五章：第一章简述了照明和显示技术的发展简史,并对发光和色度学的一些基本概念进行了概述。对目前常用荧光粉体系的晶体结构、光学特征、优缺点和改进的方向进行简单的介绍,结合现行照明显示的器件需求,提出荧光粉的改进和发展方向,指出本论文的主要工作思路。第二章为本论文的实验合成和理论计算部分。介绍本论文中用到的起始原料、合成工艺流程、合成设备、性能测试方法及装置和理论计算工具等。第三章主要论述了Ba3Si6O12N2基质荧光粉的性能研究和理论计算工作。包括两个方面：第一,详细阐述了Eu2+激活的Ba3Si6O12N2绿色荧光粉的制备工艺以及结构和光谱特性。结果表明：Ba3Si6O12N2:Eu2+荧光粉表现出优异的量子效率和色度特征：助熔剂的加入可以降低粉体的煅烧温度；通过共掺其它稀土元素或者过渡金属,或者通过利用Al-O键部分取代Si-N可使光谱可以在508-580nm的范围内自由调控。第二,利用第一性原理优化了Ba3Si6O12N2:Eu2+荧光粉的晶格结构,并对其能带结构、能态密度和吸收光谱进行了系统的模拟。研究结果表明,Ba和Eu的5d能级的耦合效应是该荧光粉具有优异发光效率的重要因素。第四章介绍了一种新型的可用于LED照明和PDP显示器件的一种新型硅基氧氮化物BaSi3Al304N5:Eu2+蓝色荧光粉。这种荧光粉基质为单斜晶系,空间群为P21/m。发射谱为470nm的宽带峰,可在真空紫外、紫外可见波段有效激发；由于晶体结构的稳定性,其具有优异的耐酸、耐高温的特征,能在600度的空气中退火后发光强度几乎不发生衰减。在不同离子的掺杂后变现出多种光学特征可以满足不同的需求,其粒径和形貌也可以通过助熔剂等合成条件进行一定的调整,符合工业上的技术要求。第五章根据荧光粉在使用中涂覆和堆积密度的要求,设计出了一种球形氧氮化物荧光粉的制备工艺。利用Si02微球为模板,在其表面包覆了SrCO3:Eu3+壳层,然后在前驱体的表面刻意地设计了一层H3B03保护层,最后在还原性气氛下成功制备出了球形的荧光粉。通过改变不同的模板和不同的还原条件,分别制备出了空心球形Sr2SiO4:Eu2+,球形SrSi2O2N2:Eu2+绿色荧光粉和球形Sr2Si5N8:Eu2+红色荧光粉等特定形貌的荧光粉。同时由于这种方法中两种反应原料间在反应时具有较大的接触面积和较小的扩散距离,使在较低温度下利用氧化物合成纯氮化物成为可能。第六章是本论文的总结,对于今后荧光粉和设计合成的思路和应用前景进行了展望。更多还原

【Abstract】 With the development of energy crisis and environmental pollution, the lighting and display area has attracted more and more attention for they constitute a large partial in the total energy consumption. The new green and ecconomic techniques have been considered to be the only way to solve this problem. In recent decades, the LED (Light emitting diodes) and PDP (Plasmon display panels) have been getting more advances due to their advantages compring with traditional lighting and display techniques. For examples, LED is famous for its small volume, low energy consumption, high color purity and excellent color index and the PDP generally considered to main technique for the large-screen and3D display techniques. What’s more, the LED and PDP could easily be realized in mass production for their simple configuration. Therefore, considering the environmental, energetic and economic elements, the new luminescence and display techniques will attract much more attentions and take an important part in future.The luminescence converting materials play important roles for they are irreplaceable in realizing different color and the high quality in the LED and PDP techniques. The phosphors used in the LED and PDP systems should have short response time, long wavelength excitation and emission spectra, high quantum efficiency and excellent stabilities under high current and temperature. While the traditional phosphors could not fulfill these demands for their low stabilies, so it is very necessary to exploit novel phosphors.The (oxo)nitridosilicate phosphors are considered to be the host materials due to their high structural and chemical stabilities and have been used as engine and fire resisting materias, such as a-SiAlON ceramics. In recent years, they have been used as the host materials for rare earch doped phosphors due to their superior mechanical stabilities and chemical interness. Therefore, it is meaningful to study the properties and synthesis of these phosphors.This paper is divided into6chapters:Chapter1of this manuscript briefly introduced the development history of luminescence and display techniques, and explained some basic concepts about the colorimetry.Chapter2is the experimental and characteristic sections. We have listed the raw materials, experimental and theoretical simulations methods, characteristic techniques used in this manuscript.In Chapter3, the optical properties and luminescence mechanism of the Ba3Si6O12N2:Eu2+green phosphors were systematically studied, including. First we had synthesized the Ba3Si6O12N2:Eu2+green phosphors and investigated the effects of temperature, codoping concentration and flux on the excitation and emission spectra. Then we theoreticatically calculated the band structure, density of states and absorption spectra by the first principle method.In Chaper4we fabricated a BaSi3Al3O4N5:Eu2+new blue emitting phosphors for the PDP and LED application and resolved its structure information by Rietveld method. This phosphor had a monoclinic system with space group of P21/m. The phosphor could be efficiently excitied from VUV to near UV region, and showed excellent chemical stability, thermal interness and acid resisting properties. The particle size could be easily adjusted by the amount of BaF2flux in the raw materials.In Chapter5, a convient method used to fabricate the spherical oxonitridosilicate phosphors with high packing density in the LED and PDP techniques were introduced.The spherical templates were derived from the spherical templates. The most important of this method was coat a H3BO3coating layer on the precursor particles, which could be reduced to h-BN protective film. This h-BN protective method could be successfully used to synthesize the spherical Sr2SisN8:Eu2+red phosphors, SrSi2O2N2:Eu2+green phosphor and hollow spherical Sr2SiO4:Eu2+green phosphor.In Chapter6we gave a brief summary of this paper. We pointed out the defects of this paper and predicted the direction in the investigation of phosphors in the future.更多还原