【作者】 王玲玲；

【导师】 刘益春；

【作者基本信息】 东北师范大学 ， 材料物理与化学， 2010， 博士

【摘要】 ZnO是具有高激子束缚能（60 meV）的宽带隙（3.37 eV）半导体材料。由于其独特的半导体及压热电性质,ZnO特别是ZnO纳米材料在紫外发射器件、场发射器件、纳米发电机、太阳能电池等光电器件领域具有独特的基础研究与应用价值。本文选题立足于尺寸、形貌及表面性质可控的ZnO纳米材料的化学制备,着重研究了ZnO纳米材料光致发光和表面亲疏水性质等对材料尺寸、形貌、表面SiO₂钝化处理、表面光化学反应等的依赖性,获得了具有一定价值与原创性的研究结果。具体研究内容如下:利用1,6-己二胺（HMDA）辅助的水热方法制备了椭球体、针状以及多枝的花状结构的均一的ZnO纳米粒子,对HMDA调控粒子形貌机理进行深入分析,并详细研究了ZnO粒子形貌依赖的光致发光性质。结果表明,HMDA/Zn摩尔比是ZnO粒子形貌控制的关键因素。在高HMDA/Zn摩尔比下生成的多枝的花状结构粒子与其它两种形貌的粒子相比显示出最强的近带边的紫外发射和最大的紫外与可见的发光强度比值。这可以由HMDA对ZnO粒子生长速率的调控获得合理解释。研究表明,可通过对溶液化学参数的合理调控制备具有良好紫外发射性质的ZnO纳米材料。利用溶剂热方法制备了均一的单分散的ZnO多孔微纳米球,对溶剂热下ZnO微球的形成机理进行了深入分析,并研究了ZnO表面有机物钝化依赖的光致发光性质。结果表明,高粘度、高螯合能力的乙二醇溶剂是导致ZnO纳米晶各向同性自组装生长的关键因素。ZnO微球显示了较弱的表面缺陷相关的可见发光强度,这可由乙二醇等有机物质对ZnO表面缺陷的有效钝化来合理解释。研究表明,通过对ZnO表面的钝化处理,可实现对ZnO纳米材料可见光发射的有效控制。利用水热和仿生的聚电解质层层沉积技术在玻璃衬底表面制备了ZnO@SiO₂核壳纳米线阵列,对层层沉积制备SiO₂壳层的调控生长进行了细致分析,并深入研究了核壳纳米线表面与界面相关的光致发光性质。结果表明,SiO₂壳层厚度可通过简单调节层层沉积循环次数来理性的调控。与ZnO纳米线相比,ZnO@SiO₂核壳纳米线阵列显示了明显增强的紫外发光特性和紫外发光积分强度随激发温度升高先降低、后增强、再降低的变化趋势,这可由SiO₂壳层的加入对纳米线表面和界面缺陷的影响获得合理解释。研究表明,仿生的层层沉积技术是在高曲率ZnO纳米线表面制备SiO₂壳层的有效方法,且通过表面SiO₂钝化处理可得到增强紫外发射性质的ZnO纳米复合材料。对ZnO@SiO₂纳米线阵列膜进行疏水修饰,对其表面润湿性能进行研究。结果表明,在长时间的强紫外光照射下,ZnO@SiO₂纳米线阵列表现出了与纯ZnO纳米线阵列紫外光致亲水现象完全相反的持久的超疏水性,这可由SiO₂壳层对ZnO纳米线表面光化学反应的有效抑制来合理解释。同时将此结构应用到棉布纤维的表面,得到了兼具紫外遮蔽和紫外光下持久超疏水的多功能织物。更多还原

【Abstract】 ZnO is a direct wide band gap semiconductor, which has band gap of 3.37 eV and a large binding energy of exciton （60 meV）. Because of its diverse and unique semiconducting, piezoelectric, and pyroelectric properties, ZnO, especially ZnO nanomaterials possess unique basic research and applied values in various photoelectric device areas, such as UV-emission devices, field-emission devices, nanogenerators, and solar cells. In this thesis, we based on the controllable chemical synthesize for the size, morphology and surface property of ZnO nanomaterials, mainly studied its size, morphology, surface SiO₂ passivation treatment and surface photochemical reaction dependent properties, that is photoluminescence and surface wettability. Some valuable and original research results were acquired. The details are as following:Uniform ZnO particles with ellipsoidal, needle-like and branched morphologies were prepared by a hexamethylenediamine （HMDA）-assisted hydrothermal method. The formation mechanism of the particles controlled by HMDA were further analyzed, and the morphology-dependent photoluminescent properties of ZnO particles were also studied detailedly. Results indicated that the molar ratio of HMDA/Zn was the key factor to controll the particle morphologies. The branched particles, which prepared at high molar ratio of HMDA/Zn, showing the most intense near-band-edge ultraviolet photoluminescence and the greatest ratio of ultraviolet to visible photoluminescence comparing to other two morphologies particles. This can be well explained by considering the roles of the HMDA in the growth process of ZnO particles. The studies indicated that the ZnO nanomaterials with well ultraviolet emission properties can be prepared through rational controlled the chemical parameters in solution.Uniform and monodispersed ZnO microspheres were successfully prepared through a facile solvothermal method. The formation mechanism of ZnO microspheres in the solvothermal system was studied in-depth, and the surface organic passivation-dependent photoluminescent properties of ZnO microspheres were also studied detailedly. Results indicated that the ethylene glycol solvent with high viscosity and active chelation was the key factor to induce the isotropy self-assemble growth of ZnO nanocrystals. The microspheres exhibitted weak surface defects-dependent visible emission. This can be well explained by the effective passivation of organic materials for the surface defects of ZnO. The studies indicated that the visible emission of ZnO nanomaterials can be effectively controlled through the surface passivation treatment for ZnO.The ZnO@SiO₂ core-shell nanowire arrays were succefully prepared on the glass substrate by combing the hydrothermal method and bioinspired layer-by-layer deposition technique. The tunable growth of SiO₂ shell prepared by layer-by-layer deposition technique was analyzed detailedly, and the surface/interface-dependent photoluminescent properties of core-shell nanowires were also studied further. Results indicated that the thickness of SiO₂ shell can be conveniently controlled by the number of deposition cycles. Comparing with the bare ZnO nanowires, the ultraviolet photoluminescence of ZnO@SiO₂ core-shell nanowire arrays was obvious enhanced and its temperature dependence of ultraviolet emission intensities showed an anomalous behavior. This can be well explained by the influence of SiO₂ shell for the defects existing in the surface/interface of ZnO nanowire array. The studies indicated that the bioinspired layer-by-layer deposition technique is an effective method for the formation of SiO₂ shell on the surface of highly curved ZnO nanowires with shell thickness being well controlled, and enhanced ultraviolet emission can be acquired through the surface SiO₂ passivation treatment in composite ZnO nanomaterials.The ZnO@SiO₂ nanowire arrays were treated with hydrophobic modification and their surface wettabilities have been studied. Results indicated that under the long-term ultraviolet irradiation, different from the photo-induced superhydrophilicity of bare ZnO nanowires, the ZnO@SiO₂ nanowire arrays exhibited durable superhydrophobicity. This can be well explained by the blocking effect of SiO₂ shell on the surface photochemical reactions of ZnO nanowires. Meanwhile, this core-shell nanowire array was also applied on the surface of cotton textile, and obtained a multifunctional textile which exhibited excellent ultraviolet-blocking property together with ultraviolet-durable superhydrophobicity.更多还原