低维氧化钨纳米结构的制备与性能研究

发布时间：2018-06-05 02:39

  本文选题：纳米氧化钨 + 脉冲激光沉积　； 参考：《南京理工大学》2016年硕士论文

【摘要】：三氧化钨是一种n型宽禁带半导体氧化物,具有响应速度快、着色效率高和比电容高等优异物理和化学性能,被广泛应用于电致变色、智能显示、化学传感以及超级电容器等领域。三氧化钨性能和应用依赖于其独特的形貌和微结构,通过纳米化增大其比表面积可提高三氧化钨的电致变色、超级电容器性能。本论文采用脉冲激光沉积和溶剂热反应方法制备了低维氧化钨纳米薄膜、纳米花球和纳米星,研究了制备工艺参数对低维氧化钨纳米结构的形貌、相组成、微结构和性能影响,探究了氧化钨微观结构与其电致变色和超级电容器性能之间的关联。采用脉冲激光沉积法制备了(002)晶面择优取向的单斜相三氧化钨纳米薄膜,研究了制备工艺参数对薄膜形貌、微观结构和光学性能的影响。研究发现氧化钨薄膜的形貌、结晶性和光学带隙依赖于衬底温度、气压与激光能量密度。三氧化钨薄膜的结晶性随着气压和激光能量密度增加而提高。在衬底温度低于300℃时,氧化钨薄膜呈非晶态；随着衬底温度增加,薄膜的结晶性提高、晶粒尺寸和表面粗糙程度增大,并导致光学带隙由3.22eV降低至3.05eV。采用溶剂热法,利用普朗尼克F127为表面活性剂,制备了具有高比表面积、晶态与非晶态杂化、直径约200nm的三氧化钨纳米花球。探究了普朗尼克F127含量(0.1-0.4g)、反应温度(90-240℃)、反应时间对其形貌和结构影响,以及纳米花球的自组装过程。结果表明,添加F127会促进无规则三氧化钨纳米颗粒生长成花球状形貌,过量F127导致纳米花球变得松散,表面薄片脱落。反应温度升高,三氧化钨由球状向花球状再向带状转变,相结构由非晶、正交二氧化钨与立方三氧化钨混合结构,转化为纯立方相三氧化钨,并最终转化为六方相三氧化钨；随着反应时间延长,初始的球状颗粒表面形核生长出褶皱状薄片,同时颗粒变得圆润饱满,最终生长为花球状形貌。制备的氧化钨纳米花球表现出良好的电致变色性能,着色消色对比度高于40%,着色和消色时间约2s。采用溶剂热法,通过金属钨粉和双氧水制备了高结晶性、由纳米带自组装成的六角三氧化钨纳米星,研究了乙醇与去离子水比例、反应时间和反应温度对纳米星尺寸和微观结构的影响。前驱体溶剂中乙醇含量增加,导致自组装成纳米星的纳米带宽度减小,纳米星形状趋于不规则；随反应时间增加,纳米星由中间向上下两个侧面按层状生长,每层直径逐渐减小,最终生长成为双六棱锥形。三氧化钨纳米星组装的超级电容器表现出法拉第赝电容特性,最大比电容达312.5F/g。
[Abstract]:Tungsten trioxide is an n-type wide band gap semiconductor oxide with high response speed, high coloring efficiency and excellent physical and chemical properties of specific capacitance. It is widely used in electrochromic and intelligent display. Chemical sensing and supercapacitors and other areas. The properties and applications of tungsten trioxide depend on its unique morphology and microstructure. By increasing its specific surface area, the electrochromic properties of tungsten trioxide and the properties of supercapacitors can be improved. In this paper, low-dimensional tungsten oxide nanocrystalline films, nanospheres and nanometers were prepared by pulsed laser deposition and solvothermal reaction. The effects of preparation parameters on the morphology, phase composition, microstructure and properties of low-dimensional tungsten oxide nanostructures were studied. The relationship between the microstructure of tungsten oxide and its electrochromic and supercapacitor properties was investigated. The monoclinic tungsten trioxide nanocrystalline films with preferential orientation of crystal plane were prepared by pulsed laser deposition. The effects of preparation parameters on the morphology, microstructure and optical properties of the films were studied. It is found that the morphology, crystallinity and optical band gap of tungsten oxide films depend on substrate temperature, gas pressure and laser energy density. The crystallinity of tungsten trioxide films increases with the increase of gas pressure and laser energy density. When the substrate temperature is lower than 300 鈩，

本文编号：1980077