【作者】 王林香；

【导师】 尹民； 郭常新；

【作者基本信息】 中国科学技术大学 ， 凝聚态物理， 2010， 博士

【摘要】 本论文分为五章,其中第1章概述了本论文研究的基础知识以及工作背景；从第2章到第5章分别介绍了使用两种方法合成稀土掺杂的两种镥氧化物的纳米粉末和透明陶瓷的过程,同时研究和比较了它们的微观结构和发光性能。第1章介绍了稀土功能材料,光致发光的基本原理与三价稀土离子的发光特性,概述了纳米材料、闪烁体透明陶瓷在国内外的研究、发展和取得的成果,并结合本工作具体介绍了两种制备纳米粉体及透明陶瓷的方法,同时讨论了影响透明陶瓷透明度的一些因素。第2章主要介绍了Lu2O3:Eu3+纳米粉末的共沉淀法制备过程,并与溶剂热法制备的样品进行比较。XRD和FTIR结果显示溶剂热法加快了无定形前驱物的晶化,有效地降低了高温煅烧下粉体的结晶温度。XRD和SEM结果表明共沉淀法制备的Lu2O3:Eu3+前驱粉是具有200nm棒状结构的非晶态物质,而溶剂热法制备的前驱粉主要是50nm的近球形颗粒,其主要成分是LuOOH,且于400℃煅烧下出现Lu203的相。相同初始条件下,比较了共沉淀和溶剂热法获得的Lu2O3:Eu3+粉末的颗粒度、形貌和发光性质。研究了不同沉淀剂、不同Eu3+掺杂浓度、不同煅烧温度和煅烧气氛对共沉淀法制备的Lu2O3:Eu3+粉体发光的影响,并对部分样品的衰减进行了测量,分析了Lu2O3:Eu3+粉体的荧光寿命和粉体颗粒度的关系。将煅烧获得的Lu2O3:Eu3+粉体在不使用任何添加剂的情况下,使用干压成型制成素坯,于先真空后氮气烧结方式下获得了Lu2O3:Eu3+透明陶瓷。初步比较了不同制备条件下Lu2O3:Eu3+透明陶瓷的透明度,分析了一些具体影响陶瓷透明度的因素。第3章介绍了溶剂热法制备LuAG:Ce3+纳米粉体,并研究其发光性质。FTIR和XRD测量结果表明,溶剂热法合成的LuAG:Ce3+前驱粉体的主要成分是AlOOH,煅烧温度400℃下有Lu2O3相的出现,而未经过溶剂热法制备的前驱粉在800℃下煅烧还是非晶态。比较了不同的沉淀剂、不同醇水体积比、不同煅烧温度对溶剂热法合成LuAG:Ce3+粉体形貌的影响。研究了不同Ce3+掺杂浓度、不同的沉淀剂和不同煅烧温度下,溶剂热法合成LuAG:Ce3+粉体的发光,实验结果表明当Ce3+的掺杂浓度为1%,使用碳酸氢铵加氨水作为混合沉淀剂,在1000℃下进行煅烧,溶剂热法获得的LuAG:Ce3+纳米荧光粉的发光强度较强。LuAG:Ce3+荧光粉5d→4f的发射谱是位于450-650nm波长范围内的两个发射带叠加组成的宽带,其很好的与硅光电二极管灵敏度曲线匹配。第4章用共沉淀方法和溶剂热方法,使用碳酸氢铵加氨水作为沉淀剂制备了LuAG:Ce3+纳米粉末及透明陶瓷。XRD、FTIR、SEM实验结果表明,共沉淀方法获得的LuAG:Ce3+前驱粉体具有无定形片状结构,其主要成分是碳酸盐NH4Al(OH)2CO3 and Lu2(CO3)3·nH2O,而溶剂热法获得的LuAG:Ce3+前驱粉体包含一些八面体形状的物质,其成分主要是由AlOOH和Lu(OH)3组成的氢氧化物。在1100℃煅烧条件下,共沉淀法制备的LuAG:Ce3+粉体,其颗粒呈现近球形,分散性好,分布较为均匀,粒径约为80-100nm；溶剂热法在同样煅烧条件下获得的LuAG:Ce3+粉体,团聚较为严重,由粒径30-50nm不规则的小颗粒所组成。比较了不同煅烧温度和气氛下,共沉淀和溶剂热法制备的LuAG:Ce3+粉体的发光。在同样初始条件下,溶剂热法制备的LuAG:Ce3+粉体的激发和发光强度较强。将获得的LuAG:Ce3+纳米粉末,在没有任何添加剂情况下压片,于先真空后氮气烧结的方式下制备了透明陶瓷。比较了两种方法制备LuAG:Ce3+陶瓷的微观结构和透明度以及具体实验中影响陶瓷透明度的因素。分析了两种方法制备的LuAG:Ce3+透明陶瓷的激发和发射谱,比较了不同激发波长下的发光强度变化规律,并分析了原因。与共沉淀法相比,溶剂热法制备的LuAG:Ce3+粉体和透明陶瓷的激发和发光强度都较强,但其制备样品的时间相对较长,产量相对较低,制备过程需要进一步优化。在第5章中,通过将溶剂热法(270℃保温2h)获得的LuAG:Ce3+前驱粉末直接压片,在无任何添加剂情况下,于先真空后氮气气氛烧结的方式下制备了LuAG:Ce3+透明陶瓷。研究了该透明陶瓷在紫外可见以及真空紫外区的光谱性质。在不同激发波长激发下,研究了所合成LuAG:Ce3+透明陶瓷的发光。并与第4章得到的LuAG:Ce3+透明陶瓷的微观结构、透明度及发光进行比较,发现该方法制备的LuAG:Ce3+透明陶瓷,其制备工艺简单,透明度有了明显的改善,发光较强。更多还原

【Abstract】 The thesis contains five chapters. Chapter 1 outlines the basics and working background of this thesis. Chapter 2 to chapter 5 introduced the synthesis of rare earth doped two kinds lutetium oxide functional nano-materials and transparent ceramic materials using two methods, and theirs microstructural and luminescent properties were analyzed and compared.In chapter 1, the introductions of rare earth functional materials, the basic principles of photoluminescence and the luminescence properties of trivalent rare earth ion luminescence are given. The researches, developments and achievements of nano-materials and transparent ceramics scintillator are stated at home and abroad. Two methods for the preparation of nano powders and transparent ceramics in this work are introduced in detail, and some impact factors on transparency of transparent ceramics are discussed.In chapter 2, Lu2O3:Eu3+ nano-particles and transparent ceramics were prepared by co-precipitation and solvo-thermal methods, respectively. XRD and FTIR results showed that the solvo-thermal treatment accelerated the crystallization of amorphous precursor and effectively decreased the crystallization temperature. XRD and SEM results showed that the precursor powders of Lu2O3:Eu3+ prepared by co-precipitation were amorphous with the rod structure about 200nm; the precursor powders of Lu2O3:Eu3+ prepared by solvo-thermal method mainly included nearly spherical particles with 50nm, whose main components were LuOOH, and the phase of Lu2O3 appeared at calcination temperature 400℃. The powder particle size, morphology and luminescence properties of the obtained Lu2O3:Eu3+ by co-precipitation and solvo-thermal were compared. The luminescence of the obtained Lu2O3:Eu3+ powders by co-precipitation under the different precipitation agents, different Eu3+ doped concentrations, different calcination temperature and calcination atmosphere was dicussed. The fluorescence decay curves of the obtained Lu2O3:Eu3+ powders at different calcining temperature and atmosphere were measured. The relations of fluorescence lifetimes and particle-size for powders were analyzed. The resultant Lu2O3:Eu3+ powders were pressed into tablets without any additives by dry-pressing moulding, sintered in vacuum and then nitrogen atmosphere at high temperature, and Lu2O3:Eu3+ transparent ceramics were obtained. The transparencies of the obtained Lu2O3:Eu3+ transparent ceramics under different conditions were compared, and some factors that affect the transparency of ceramics were analyzed.In chapter 3, the synthesis and luminescence properties of LuAG:Ce3+ nano-powders by solvo-thermal method were investigated. FTIR and XRD measurements showed that the precursor powders of LuAG:Ce3+ by solvo-thermal treatment, theirs main components were AlOOH, and cubic phase Lu2O3 appeared at calcination temperature 400℃, but that precursor powders prepared by co-precipitation were still amorphous at calcination temperature 800℃. The influences on the LuAG:Ce3+ powders morphologies under different precipitant, different volume ratio of ethanol and water, different calcination temperature were compared. Dependences of illumination intensity of LuAG:Ce3+ powders on Ce3+ concentration, the precipitation agents and the calcination temperature were discussed. The results showed that, the 1% Ce3+ doping concentration, ammonium hydrogen carbonate and ammonia water as mixture precipitation agent, under the calcination temperature 1000℃, the luminescence of the obtained LuAG:Ce3+ nano-powder was stronger. Emission spectrum of LuAG:Ce3+ phosphor was located at 450-650nm, including overlap of two broad emission bands, which was matched well with the sensitivity curve of silicon photodiode.In chapter 4, LuAG:Ce3+ nano-powders and transparent ceramics were obtained by co-precipitation and solvo-thermal method using ammonium hydrogen carbonate and ammonia water as a mixture precipitation agent, respectively. XRD, FTIR, SEM results showed that the prepared precursor powder of LuAG:Ce3+ by co-precipitation contained amorphous sheet structure, its main components were carbonate NH4A1(OH)2CO3 and Lu2(CO3)3 nH2O, but the obtained that by solvo-thermal method existed some octahedral shape material construction, whose main components were AlOOH and Lu(OH)3. In the same calcination conditions, the prepared LuAG:Ce3+ resultant powder by co-precipitation was almost spherical, well dispersed and uniform distribution with particle size about 80-100nm, and the obtained that by solvo-thermal method contains seriously agglomerative and irregular morphological particles with particle size about 30-50nm. The luminescence of the obtained LuAG: Ce3+ powder by solvo-thermal method was stronger than that of powder prepared by co-precipitation method. The luminescence properties of the obtained LuAG:Ce3+ powders by co-precipitation method at different calcination temperature and atmosphere were compared. The LuAG:Ce3+ powders prepared by above two methods were pressed into tablets without any other additives, calcined in the vacuum and then nitrogen calcinations, and the LuAG:Ce3+ transparent ceramics were obtained. The microsructures and transparencies of the obtained LuAG:Ce3+ transparent ceramics by above two methods were compared. Some specific impact factors that affected the transparency of ceramics were discussed. The excitation and emission spectra of the obtained LuAG:Ce3+ ceramics in two ways were analyzed. The luminescence of Ce3+ under the different excitation wavelengths was analyzed. LuAG:Ce3+ powders and transparent ceramics prepared by solvo-thermal method, their excitation and emission intensities were all stronger than that prepared by co-precipitation method, but the preparation process and cycle of solvo-thermal method was relatively long, and yields were relatively lower, so this solvo-thermal preparation process should be further optimized.In chapter 5, the precursor powders of LuAG:Ce3+ obtained by mixed solvo-thermal at 270℃for 2h were directly pressed into tablets, sintered in vacuum and then in nitrogen without any additive, and LuAG:Ce3+ transparent ceramics were synthesized. The luminescence in ultraviolet and vacuum ultraviolet region for LuAG: Ce3+ transparent ceramics was measured and investigated. The photoluminescence of LuAG:Ce3+ transparent ceramics under the different excitation wavelength was analyzed and luminescence mechanism for Ce3+ was discussed. The microstructures, transparencies and luminescence properties of the obtained LuAG:Ce3+ transparent ceramics in chapter 5 were compared with that in chapter 4. It was found that the prepared LuAG:Ce3+ transparent ceramic in chapter 5, its preparation process was simple, the transparency of ceramics was better and its luminescence was stronger relatively.更多还原