【作者】 吴燕利；

【导师】 李永绣；

【作者基本信息】 南昌大学 ， 微纳米材料科学与工程， 2013， 博士

【摘要】 稀土发光材料在显示、照明、X射线影像、太阳能光电转换、激光以及生物工程等方面都有广泛的应用前景,因而日益受到人们的重视。随着科学技术发展要求的提高和资源节约型社会的发展要求,稀土发光材料也正在向纳米化、球形化和多功能化的方向发展。与此同时,纳米级别的稀土发光材料还在免疫分析、生物传感、生物成像、载药等方面具有潜在应用价值。因此,本研究将稀土离子的荧光特性与Gd3+的顺磁性相结合,采用不同的合成方法,制备一系列磁性-荧光双功能Gd2(CO3)3:Ln3+纳米粒子。同时寻求一种适合于工业应用的简单化学法合成小尺寸高亮度的磷酸镧铈铽(LAP)绿色荧光粉。具体内容包括：[1]以CTAB为表面活性剂,正丁醇为助表面活性剂,正己烷为溶剂,以GdCl3和Na2CO3为原料,采用反相微乳液法,制备Gd2(CO3)3:Tb纳米粒子,并以在该微乳液中添加TEOS的方式,一步合成Gd2(CO3)3:Tb@SiO2纳米粒子。采用扫描电镜(SEM)、透射电镜(TEM)对纳米粒子的形貌和粒径进行表征,采用红外光谱(IR)、元素分析(EDS)等对纳米粒子的成分进行分析,结果表明纳米粒子为核壳结构,其核为Gd2(CO3)3:Tb,粒径为8-10nm,外面包裹的SiO2的厚度为3-5nm。该纳米粒子在波长为λ=225nm的光源激发下,发出发射光谱在544nm左右的绿光,发光性质良好；且在溶液体系和细胞环境中均可以进行良好的T1磁共振成像和荧光成像,该粒子能对NCI-H460肺癌细胞以及对SGC7901胃癌细胞成功标记,通过MTT法测试出纳米粒子在62.5μg/mL-500μg/mL的浓度范围内的毒性很小,具有很好的生物相容性。[2]采用尿素均相沉淀法制备出粒度均匀的Ln3+掺杂Gd2O(CO3)2纳米粒子及球形Gd2O3:Eu粉体,利用SEM、TEM、IR、XRD等对纳米粒子的结构和颗粒特征进行了分析,考查了沉淀时间以及表面活性剂的添加对纳米粒子的形貌和粒径的影响,并对Eu3+/Tb3+掺杂的纳米粒子的荧光性质进行了测试。结果表明,随着沉淀时间的延长,纳米粒子的形貌由球形变为菱形,尺寸亦不断增大,加入表面分散剂后,粒子的分散性更好。球形Gd2O(CO3)2:Tb@PVP纳米粒子在波长为λ=274nm的光源激发下,发出543nm左右的绿光,且该纳米粒子在溶液体系和细胞环境中均可以进行良好的T1磁共振成像和荧光成像,通过两种功能的成像优势的结合提高了检测肿瘤细胞的灵敏度和准确度,表明其在生物应用方面的潜在应用价值。[3]采用水热法制备出尺寸细小、均匀的球形Gd2(CO3)3纳米粒子,通过掺杂Eu3+及Tb3+,使其具有荧光性质。采用SEM、TEM、IR、XRD等对纳米粒子的物相和颗粒特征进行了分析。结果表明：所合成的纳米粒子的物相、形貌、尺寸均随着水热条件的改变而又所改变,并最终影响纳米粒子的性质。初步探讨了Gd2(CO3)3纳米粒子的水热结晶机理,并总结了在水热条件下制备适合生物应用的球形Gd2(CO3)3纳米粒子的反应条件。[4]通过机械化学研磨法制备出LaPO4：Ce,Tb前驱体,再将前驱体在还原气氛中煅烧得到LaPO4:Ce,Tb荧光粉。采用SEM)、XRD、荧光光谱(FL)对产物的结构、形貌和荧光性质进行了表征,结果表明研磨时间、煅烧温度、是否洗涤、及助溶剂的添加等条件对荧光粉亮度及形貌均有影响。采用该方法可以制备出比商用铝酸盐绿粉(CAT)亮度更高、颗粒更为细小均匀的LaPO4:Ce,Tb绿色荧光粉。该方法温和、简便、环境友好、具有工业应用价值。[5]采用共沉淀法制备磷酸镧铈铽前驱体,再将前驱体在还原气氛中煅烧,得到类球形的LAP绿色荧光粉。采用SEM、XRD、FL对产物的结构和荧光性质进行了表征,考查沉淀条件对产物的物相、形貌、荧光性质的影响。结果表明,沉淀陈化时间、加料方式、离子浓度、pH等对产物的形貌均有影响。更多还原

【Abstract】 Rare Earth Luminescent materials have attracted more attention due to their abroad applications in displaying, lighting, bioimaging, solar photoelectric conversion, laser and biological engineering, In order to meet the demand of the resource-saving society, rare earth luminescent materials are also developing to the direction of multi-functionallization, nanocrystllization and spheroidization. Meanwhile, the nanosacle rare earth luminescent material has the potential application value in biosensing, immunoassay, biological imaging, and drug loading. The aim of this study was to prepare Ln3+doped Gd2(CO3)3magnetic-fluorescent bifunctional nanoparticles through different synthesis methods and LaPO4:Ce,Tb(LAP) green fluorescent powders with small size and high emission brightness via simple chemical methods for industrial application. The concrete content includes:[1]A simple reverse microemulsion method and coating process was introduced to synthesize silica-coated Gd2(CO3)3:Tb nanoparticles. The morphology and particle size of the nanoparticles were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy spectrum(EDS), and infrared spectrum(IR). The results showed that nanoparticles have obvious core-shell structure and perfect spherical morphology. The particles with an average diameter of16nm, including8-10nm of Gd2(CO3)3:Tb core and3-5nm of SiO2shell, can be dispersed well in water. As in vitro cell imaging of the nanoprobe shows, the nanoprobe accomplished delivery to gastric SGC7901cancer cells successfully in a short time, as well as NCI-H460lung cancer cells. Furthermore, it presents no evidence of cell toxicity or adverse affect on kidney cell growth under high dose, which makes the nanoprobe’s optical bio-imaging modality available. The possibility of using the nanoprobes for magnetic resonance imaging is also demonstrated, and the nanoprobe diplays a clear T1-weighted effect and could potentially serve as bimodal T1-positive contrast agent. Therefore, the new nanoprobe formed from carbonate nanoprobe doped with rare earth ions provides the dual modality of optical and magnetic resonance imaging. A new type of dual modal nanoprobe to combine optical and magnetic resonance bioimaging was developed.[2] Ln3+doped Gd2O(CO3)2nanoparticles with uniform particle size have been prepared via urea homogeneous precipitation. The properties of as-prepared nanoparticles were characterized by SEM, TEM, XRD and IR. The fluorescent properties and magnetic resonance relaxivity were measured and the effect of the sedimentation time on the morphology and particle size was examined. The results showed that the morphology of the nanoparticles was changed from spherical to diamond with reflux time increased from2h to10h, and the size was growing too. The spherical Gd2O(CO3)2:Tb@pvp emit bright green light at about543nm under274nm excitation, and would be a good T1MRI contrast agent in solution and a good optical imaging agent in cell environment. The sensitivity and accuracy of detection of the tumor cells would be improved through combining these two functions. It indicated that Gd2O(CO3)2:Tb nanoparticles provides the dual modality of optical and magnetic resonance imaging. At the same time, nanosized spherical Gd2O3:Fu fluorescent powder could be obtained by calcination of the Gd2O(CO3)2:Fu precipitate at800℃.[3] Spherical Ln3+doped Gd2(CO3)3nanoparticles with uniform particle size were prepared by a simple hydrothermal method. The morphology and particle size of the as prepared particles were characterized by SEM, TEM, XRD and IR. The results showed that the morphology, phase structure, particle size and the properties of the nanoparticles would be changed with the hydrothermal conditions. The hydrothermal crystallization mechanism of the nanoparticles was preliminary discussed.[4] LaPO4:Ce,Tb phosphor was prepared by a rreduction calcination of the precursor obtained by the simple mechanical grinding method. The results of SEM, XRD and FL showed that the luminance and morphology of the phosphors were affected by the synthesis conditons including grinding time, calcination temperature, washing method and the cosolvent used. The as-prepared nanosized green LaPO4:Ce,Tb phosphors showed higher brightness and smaller size than the current commercial aluminate green powder (CAT). This method provides potential applicaton in large scale industrial production because of its characterization of simple, mild, and environment friendly. [5] LaP04:Ce,Tb phosphor was prepared by a reduction calcination of the precursor obtained by a simple co-precipitation method. The results of SEM, XRD and FL showed the luminescence and morphology of the phosphors were also influenced by the aging time, feeding mode, ionic concentration and pH value.更多还原