【作者】 陈中；

【导师】 黄靖云； 叶志镇；

【作者基本信息】 浙江大学 ， 材料科学与工程， 2012， 硕士

【摘要】 碱金属铌酸盐体系中的诸多化合物都具有很好的铁电性能、压电性能、介电性能、声光性能、电光性能、荧光性能、光折变性能以及非线性光学性能等,同时还具有良好的机械性能和化学稳定性等特点,是集诸多优点于一身的多功能光电材料,因此引起了众多学者的广泛兴趣。目前许多碱金属铌酸盐已得到了广泛应用,例如铌酸钾、铌酸锂等材料已被广泛用在许多电光设备、激光器变频和表面声波等器件中。随着微纳加工技术的发展,微纳结构材料以其在电学、光学等方面独特优异的性能受到了人们的广泛关注。微纳结构材料在电、光器件方面具有十分巨大的应用前景,例如可以制作生物系统荧光探针、量子点激光器、二极管、纳米传感器,可广泛应用于逻辑集成电路、集成光路、光催化、纳米机械系统等领域。随着现代信息产业技术的迅速发展,对器件的微型化要求越来越高,此时微纳材料的制备加工技术将成为器件微型化的基础、成为现代信息技术发展的重要支柱。虽然大尺寸块体碱金属铌酸盐以其优异的性能已得到了广泛的应用,但微纳结构碱金属铌酸盐的研究工作仍处于起步阶段。因此微纳结构碱金属铌酸盐材料的制备工作及其性能的研究对现代生物医学、新信息技术等高新技术产业的发展都有十分重要的意义。本文采用水热法,以KOH和去离子水作为反应原料,可以在多晶A1203衬底上制备得到KNbO3纳米针和微纳结构K3Nb7O19六棱片。同时在没有衬底的条件下制备得到了KNbO3纳米线,以KNbO3纳米线作为反应物分别与Li2CO3、LiNO3发生熔盐反应可以制备得到Li3Nb04、LiNbO3纳米颗粒。以Nb粉和尿素作为反应物采用水热法制备得到NH4Nb3O8纳米线,以NH4Nb3O8纳米线作为反应物与Li2CO3发生熔盐反应可制备得到沿c轴取向生长的菱方结构LiNbO3纳米线。随后对制得微纳结构碱金属铌酸盐的形貌、物相、结构等进行了表征分析,并对微纳结构碱金属铌酸盐的压电性能、荧光特性以及粉末倍频效应进行了进一步的深入研究,本文中微纳结构碱金属铌酸盐材料的制备及其性能研究方面的相关工作为微纳结构碱金属铌酸盐的进一步发展和应用提供了很好的指导意义。本文中通过实验还发现以下结果：(1)所制备得到KNbO3纳米针、KNbO3纳米线、K3Nb7O19六棱片、Li3Nb04纳米颗粒、LiNbO3纳米颗粒以及LiNbO3纳米线的结晶性很好；(2) K3Nb7O19六棱片和LiNbO3纳米线都具有很好的压电响应性能,压电系数的最大值可分别达到80pm/V和100 pm/V左右,都是很好的微纳结构无铅压电材料；(3)微纳结构LiNbO3、KNbO3在室温下观察不到明显的荧光现象,Li3NbO4纳米颗粒在室温下具有很好的荧光特性,Li3NbO4纳米颗粒在247nm的氙灯光源的激发下可以激发出376nm荧光,其对应的荧光寿命约为119.6μs, Li3NbO4纳米颗粒可以作为很好的纳米荧光粉材料；(4) Li3NbO4纳米颗粒没有明显的粉末倍频(SHG)效应,KNbO3纳米颗粒、KNbO3纳米针、KNbO3纳米线、LiNbO3纳米颗粒以及LiNbO3纳米线都显示出了很好的粉末倍频现象,它们相对于250～300目K103粉末的平均相对倍频转换效率分别为0.95、0.28、0.13、1.2、0.52。更多还原

【Abstract】 Many compounds in the system of alkali niobate have attracted extensive research interests due to their outstanding ferroelectric, piezoelectric, dielectric, acoustic-optical, electro-optical, fluorescence, photorefractive and nonlinear optical properties, as well as their superior mechanical and chemical stability. This kind of multi-functional optical and electric material has many advantages. At present, alkali niobate materials have been widely used, such as LiNbO3 and KNbO3 which have been widely used in electro-optical devices, frequency converter of laser, and surface acoustic wave devices.With the development of micro-/nano fabrication technology, micro-/nano structural materials have drawn increasing attention because of their advanced performance compared to their bulk counterparts. Micro-/nano structural materials have great potential applications in such electric and optical devices as biological imaging probes, quantum dot lasers, diode, and nano sensors. They could also be used in logical integrated circuits, light integrated circuits, photocatalysis, and nanoelectromechanical systems (NEMS). With the rapid development of modern information industry, the demands of miniaturization of the devices have become increasingly high. The preparation process technology of micro-/nano structural materials will become the basis for device miniaturization and the development of modern information technology. Although bulk alkali niobate materials have been widely used due to their excellent properties, the research of micro-/nano structural alkali niobate materials is still in its infancy. Therefore, the synthesis of micro-/nano structured alkali niobate materials and the researches on their properties are very important for the development of modern biomedical research, new modern information technology and other high-tech industries.In this thesis, KNbO3 nanoneedles and K3Nb7O19 micro-hexagonal tablets are synthesized through hydrothermal reaction with KOH, H2O and Nb2O5 as source materials by using a polycrystalline Al2O3 as substrate. KNbO3 nanowires are also prepared without any substrate. Li3NbO4 and LiNbO3 nanoparticles are synthesized by using KNbO3 nanowires as starting materials based on the molten salt reaction with Li2CO3 and LiNO3 powders in the KC1 melt. NH4Nb3O8 nanowires are prepared through hydrothermal reaction by using Nb and urea solution as source materials, and rhombic LiNbO3 nanowires along the c-axis were synthesized by using the wire-like g as starting materials based on the molten salt reaction with Li2CO3 powders in the KC1 melt. Subsequently, the obtained micro-/nano structured alkali niobate materials are characterized to analyze their morphologies. phase compositions. and structures. Their piezoelectric properties, fluorescence properties and powder SHG effects are also further studied. The synthesis of micro-/nano structured alkali niobate materials and the related research works on their properties will provide a good guide for the further developments and applications of micro-/nano structured alkali niobate materials.In this thesis, the results are presented as follows:(1) The as-prepared KNbO3 nanoneedles, KNbO3 nanowires, K3Nb7O19 micro-hexagonal tablets, Li3NbO4 nanoparticles, LiNbO3nanoparticles, and LiNbO3 nanowires are all highly crystallized;(2) Piezoresponse force microscopy measurements show strong piezoactivities of the K3Nb7O19 micro-hexagonal tablet and LiNbO3 nanowire. The max d33 value could reach 80pm/V and 100pm/V, respectively.(3) At room temperature, there are no obvious luminescence properties of LiNbO3 and KNbO3. Li3NbO4 nanoparticles, however, exhibit excellent luminescence property. The photoluminescence (PL) spectra excited at 247 nm have a strong blue emission band maximum at 376 nm, and it has a long lifetime which is up to 119.6μs. So it could be used as a good kind of nanophosphors.(4) Li3NbO4 nanoparticles have no powder SHG effect, while KNbO3 nanoparticles, KNbO3 nanoneedles, KNbO3 nanowires. LiNbO3 nanoparticles, and LiNbO3 nanowires exhibit excellent powder SHG effect. Compared to 250～300 mesh KIO3 powders, their relative powder SHG transfer efficiency are around 0.95,0.28, 0.13,1.2, and 0.52, respectively.更多还原