对ZnO纳米片薄膜的硫化—氧化后处理及其光电极应用研究

发布时间：2018-05-28 15:38

  本文选题：染料敏化太阳电池 + 水热法　； 参考：《南京大学》2014年硕士论文

【摘要】：染料敏化太阳电池(Dye-sensitized Solar Cells, DSSCs),作为一种基于光电化学原理的光电转换器件,因其简单的制备工艺、相对低廉的成本及较高的光电转换效率而受到人们的广泛关注。与传统的硅基太阳电池不同,染料敏化太阳电池主要由光电极、染料、电解液及对电极四部分构成,其中,光电极承担着吸附染料和传导电子的作用,是DSSCs光电转换的核心环节之一。迄今为止研究最多的的光电极材料主要为TiO2、ZnO及SnO2等,其中以TiO2效率最高。ZnO具有和TiO2相似的半导体特性和更大的电子迁移率,更有利于光生电子的传输。而且,ZnO还可通过多样化的制备方法实现丰富的微观形貌调控,使其成为DSSCs中最有可能替代TiO2的光电极材料。目前,多种ZnO纳米结构已被应用于DSSCs光电极的制备,尤其以低维结构最多。然而作为光电极应用的低维的ZnO纳米结构,如纳米线、纳米棒、纳米管及纳米片阵列等,虽然可发挥其载流子定向迁移的优势,但是其较小的比表面积限制了染料吸附量的提高,进而限制了DSSCs器件的光捕获能力。因此,如何制备出大比表面积的ZnO纳米结构,是将其应用于DSSCs光电极需要解决的重要问题之一本论文主要是在FTO(氟掺杂的SnO2)基底上生长ZnO纳米片阵列,然后对其进行硫化-氧化处理,研究硫化-氧化处理对ZnO纳米片的结构、结晶性等的影响。最后将硫化-氧化处理前后的ZnO纳米片作为光电极应用于DSSCs中,对电池光电转换性能进行比较研究。(1)使用水热法在FTO基底上制备得到(110)取向的ZnO纳米片,用硫代乙酰胺溶液通过水热法对ZnO纳米片进行硫化处理,得到ZnS纳米片。然后在空气氛围下,不同温度下对ZnS纳米片进行热氧化处理,研究确定由ZnS向ZnO转变的温度,大约在500℃左右可得到(002)取向的ZnO纳米片。进一步计算、分析了不同温度热氧化处理对样品晶粒大小、晶格畸变的影响,发现热氧化温度越高,晶粒越大且晶格畸变度越小。最后研究不同温度热氧化处理对样品光学带隙的影响,结果显示其光学带隙都发生了一定红移。(2)将硫化-氧化处理前后的ZnO纳米片作为光电极应用于DSSCs中,并对其光电转换性能进行了比较。通过扫描电子显微镜、比表面和孔径分析仪进一步分析造成这种性能差异的原因,结果表明硫化-氧化处理能增加ZnO纳米片的比表面积,进而有助于染料的吸附,使光电转化性能有33%的提升。
[Abstract]:Dye-sensitized Solar cells (DSSCs), as a photoelectric conversion device based on photochemical principle, have attracted wide attention due to its simple preparation process, relatively low cost and high photoelectric conversion efficiency. Unlike traditional silicon based solar cells, dye sensitized solar cells are mainly composed of four parts: photoelectrode, dye, electrolyte and opposite electrode, in which the photoelectrode is responsible for the adsorption of dyes and conduction of electrons. DSSCs photoelectric conversion is one of the core links. So far, the most studied photoelectrode materials are TiO2ZnO and SnO2, among which TiO2 has similar semiconductor properties to TiO2 and larger electron mobility, which is more favorable for photoelectron transport. Moreover, it can be used to control the morphology of DSSCs by various preparation methods, which makes it the most likely photoelectrode material to replace TiO2 in DSSCs. At present, a variety of ZnO nanostructures have been used in the preparation of DSSCs photoelectrodes, especially in low dimensional structures. However, low-dimensional ZnO nanostructures, such as nanowires, nanorods, nanotubes and nanochip arrays, which are used as optoelectronic poles, may take advantage of their carrier directional migration. However, its small specific surface area limits the increase of dye adsorption, which limits the photocapture ability of DSSCs devices. Therefore, how to fabricate ZnO nanostructures with large specific surface area is one of the important problems to be solved in the application of DSSCs photoelectrodes. In this paper, ZnO nanoarrays are grown on FTO (fluorine-doped Sno _ 2) substrates. The effect of vulcanization-oxidation treatment on the structure and crystallinity of ZnO nanoparticles was studied. Finally, the ZnO nanocrystals before and after vulcanization-oxidation treatment were used as photoelectrodes in DSSCs. The photovoltaic conversion properties of the cells were compared. 1) the ZnO nanocrystals were prepared on FTO substrates by hydrothermal method. ZnO nanoparticles were vulcanized with thioacetamide solution by hydrothermal method to obtain ZnS nanoparticles. Then the ZnS nanocrystals were thermally oxidized at different temperatures in air atmosphere. The transition temperature from ZnS to ZnO was determined, and the ZnO nanocrystals were obtained at about 500 鈩，

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