【作者】 徐丽娟；

【导师】 崔屾；

【作者基本信息】 天津大学 ， 物理化学， 2008， 硕士

【摘要】 场发射显示器件（FED）是继电致发光显示器件（LED）之后的第四代显示器件。碳纳米管（Carbon nanotubes-CNTs）是制备FED场发射阴极的理想材料。丝网印刷方法是实现低成本、大面积制备CNTs场发射阴极的有效方法。纳米荧光粉不仅有可能满足CNTs-FED的特殊要求,还有可能使其质量进一步提高。本文采用化学共沉淀法制备了ZnGa₂O₄荧光粉,采用固相反应法制备了ZnGa₂O₄:Eu³⁺荧光粉;借助TEM、SEM和XRD等对所制备产物进行了表征,并对所制备的荧光粉的发光性能进行了定性测试;采用丝网印刷法制备了CNTs薄膜阴极,借助SEM表征方法考察了超声时间、制浆剂、丝网目数、研磨和高温处理对CNTs薄膜形貌的影响;分别以商品化低压荧光粉和自制的CNTs薄膜制作阳极和阴极,自主设计、组装了CNTs-FED原位发光器件及其发光性能定性测试装置。SEM和TEM表征结果显示,对于化学法制备的ZnGa₂O₄荧光粉,当ZnO与Ga₂O₃的初始投料摩尔比不同时,所得产物的颗粒尺寸和形貌各不相同;XRD定性物相分析结果表明,虽然ZnO与Ga₂O₃初始投料摩尔比不同,但制得的产物均以ZnGa₂O₄相为主;ZnGa₂O₄荧光粉的发光性能定性测试结果表明,当ZnO:Ga₂O₃=1:2时,荧光粉发较弱的绿光;当ZnO:Ga₂O₃=2:1时,荧光粉在本实验的测试条件下基本不发光。SEM表征结果显示,固相法制备的ZnGa₂O₄:Eu³⁺荧光粉颗粒形状不规则,团聚现象较严重;其发光性能定性测试结果表明,掺杂Eu³⁺离子后的ZnGa₂O₄荧光粉由发绿光改为发红光。SEM表征结果表明,采用丝网印刷法制备的CNTs薄膜在低倍的SEM照片中显示排列比较规整;CNTs在浆料中超声时间越长,所制备的薄膜中CNTs的分散状态越好;CNTs经研磨后制成的薄膜表面的单位面积CNTs端点明显增多;与未加制浆剂制备的CNTs薄膜相比,加制浆剂制备的CNTs薄膜表面比较平整,CNTs分布较均匀,分散状态较好;未加制浆剂制备的CNTs薄膜经450℃恒温2h热处理后其表面更加洁净,杂质显著减少,而加制浆剂制备的CNTs薄膜只有经过430℃恒温2h热处理后,大部分CNTs才裸露出来,但薄膜表面仍有一些制浆剂分解后的残余物。本文的研究结果对于推动CNTs-FED的研制具有一定的积极作用。更多还原

【Abstract】 The field emission display （FED） is the fourth generation display, following the light emission display （LED）. The carbon nanotubes（CNTs） is the ideal material for fabrication of the field emission cathode （FEC）. Screen-printing is an effective method to make the large-area FEC at a low cost. The nanophosphors will not only satisfy the special requirements of CNTs-FED, but also improve its quality.In this work, the ZnGa₂O₄ phosphor was prepared by chemical co-precipitation method and ZnGa₂O₄:Eu³⁺ phosphor was prepared by solid-phase reaction. The phosphors were characterized by SEM, TEM and XRD, and their luminescent properties were investigated qualitatively. The CNTs film cathodes were prepared by screen-printing method. The effects of ultrasonication time, plasm, screen mesh size, grinding and high-temperature treatment on the morphology of CNTs film were investigated by SEM measurement. The anodes were prepared with the commercial phosphors. The apparatus to in-situ test the luminescent properties of CNTs-FED was designed and assembled by ourselves.The results of SEM and TEM measurements show that the particle sizes and the morphology of ZnGa₂O₄ phosphors prepared by chemical method are different, if the molar ratio of the raw materials ZnO and Ga₂O₃ is changed. The analysis results about XRD patterns indicate that the main phase in the products is ZnGa₂O₄, under the molar ratio of ZnO and Ga₂O₃ at both 1:2 and 2:1. The qualitative measurements of their luminescent properties show that when the molar ratio of ZnO and Ga₂O₃ is 1:2, the phosphor emits weak green color, but when the molar ratio is 2:1, the phosphor is nonluminescence. The results of SEM measurement show that the morphology of the ZnGa₂O₄:Eu³⁺ phosphor prepared by solid-phase reaction is not regular. The Eu³⁺-doped ZnGa₂O₄ phosphor emits red color.The results of SEM measurement show that the surface of the CNTs films presents some regular grid distribution in the SEM images of low magnification. The distribution of the CNTs is better with the increasing ultrasonication time. The tips per unit area on the CNTs films were increased obviously, if the raw CNTs were grinded beforehand. The CNTs in the films are more uniform and well-dispersed, if the plasm was added, compared with those without plasm added. After calcining for 2h at 450℃, the CNTs films without the plasm added became much clearer than before. Only being calcined for 2h at 430℃, many CNTs can be seen in the film which was prepared with the plasm added.The above results will play an active role in promoting the development of CNTs-FED.更多还原