Co_xS_y及其石墨烯复合材料制备及在DSSC中的应用研究

发布时间：2018-01-13 07:43

本文关键词：Co_xS_y及其石墨烯复合材料制备及在DSSC中的应用研究　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：染料敏化太阳能电池,又称第三代太阳能电池,以其较低的成本、相对较高的效率引起了人们的广泛关注。典型的染料敏化太阳能电池通常由三部分组成:光阳极(经过染料分子敏化的Ti O2介孔膜)、电解质(通常为I3ˉ/Iˉ氧化还原电对)及对电极。其中,对电极作为染料敏化太阳能电池的重要组分,起着收集外电路中电子并将电解质中I3ˉ还原为Iˉ的作用。目前,由于其优越的电催化活性,金属铂一直被作为常用的对电极材料。但是铂的储量有限,而且价格居高不下,大大增加了染料敏化太阳能电池的成本。因此,开发低成本、高催化活性的非铂对电极材料具有重要意义。近年来,硫化钴作为低成本的对电极材料被引入染料敏化太阳能电池领域,对于I3ˉ的还原已表现出良好的电催化性能,因此硫化钴被认为是有望替代昂贵Pt电极的新型对电极材料。但是硫化钴本身的电导性不高、常规的合成方法中毒性硫源的使用会使反应过程释放有毒气体硫化氢,这些问题成为其大规模应用的障碍。因此,本文旨在发展环境友好、过程简单的方法合成高效的硫化钴对电极,同时采用高电导材料与其复合以克服其电导率低的问题,并且使二者发挥协同催化作用以改善材料的催化性能。本论文文主要研究内容如下:采用有机分子诱导的方法成功合成了三维花状硫化钴(Co S)分级结构。阐述了三维分级结构的生长机制,并首次将三维花状Co S分级结构作为电极材料引入染料敏化太阳能电池领域,考察了其电催化性能及光伏性能。电化学测试表明,对于I3ˉ的还原,三维花状Co S分级结构具有良好的电催化活性,归因于构成分级结构的纳米片结构不仅促进了电解质的扩散,而且增大了材料的比表面积进而提高了其催化活性。结果,基于三维花状Co S分级结构对电极的染料敏化太阳能电池获得了与基于铂对电极的器件相近的效率。采用一步水热法合成了石墨烯包覆的硫化钴三维分级多孔球复合(CSHPS-G)材料,并且通过电化学测试研究了单组分的硫化钴(Co S)、还原的氧化石墨烯(RGO)及CSHPS-G的电催化活性。研究表明,相比于单组分材料,CSHPS-G复合材料表现出了更好的电催化性能,进而使器件获得了较高的效率。这是因为复合材料的多孔结构不仅为电解质提供了有效的扩散通道,增加了催化反应的活性位点,而且由于石墨烯的包覆,在CoS球之间创造了三维导电网络,弥补了Co S材料本身导电性差的缺点同时有效抑制了石墨烯片层在高温条件下的团聚。结果,基于CSHPS-G复合材料对电极的器件获得了高于铂电极的效率。采用层层自组装结合热解法直接在FTO表面制备了硫化钴纳米粒子修饰的石墨烯透明薄膜(CSG)电极。避免了常规电极制备过程中浆料混合、刮涂等复杂过程。更重要的是制备的薄膜厚度可控制在纳米尺度范围,而且高度透明,有望应用于透明电子器件领域。电化学测试说明CSG对碘电对间氧化还原反应具有良好的电催化活性。J-V测试中,基于CSG透明电极的器件表现了与相应Pt基器件相近的光伏特性。发展了一种改性的自组装技术:利用离子及功能化石墨烯所带电荷不同的特点,通过静电吸附的方法直接在FTO导电基底上制备了功能化石墨烯/硫化钴复合薄膜(CFG)电极。此过程不仅避免了常规层层自组装过程中聚电解质及其它辅助材料的使用,而且利用了功能化石墨烯表面官能团与硫化钴纳米粒子间的相互作用,促进了硫化钴纳米粒子的分散。同时对复合薄膜电极进行电化学测试,CFG电极表现了良好的电催化性能。因此,光电测试中,基于CFG薄膜电极的器件获得了与Pt基器件相近的电池效率。
[Abstract]:Dye-sensitized solar cells, also known as the third generation solar cells, with its low cost, relatively high efficiency has attracted widespread attention. The dye-sensitized solar cell typically consists of three parts: the light anode (after Ti O2 mesoporous film dye sensitized), electrolyte (usually I3 - /I - redox couple) and the counter electrode. The electrode as an important group of dye-sensitized solar cells, plays in the circuit and the collected electronic effect in the electrolyte I3 - reduced to I -. At present, due to its superior electrocatalytic activity of platinum metal, has been used as the electrode material but platinum reserves are limited, and the price is high, greatly increasing the dye-sensitized solar cell cost. Therefore, the development of low cost, non platinum and high catalytic activity is of great significance to the electrode material. In recent years, as a low cobalt sulfide The counter electrode materials have been used in dye-sensitized solar cell field, for the reduction of I3 - has exhibited excellent electrocatalytic properties, so the cobalt sulfide is expected to replace the expensive Pt electrode model of electrode material. But the conductivity of cobalt sulfide itself is not high, the use of conventional synthetic methods of toxic sulfur source the reaction process of releasing toxic gas hydrogen sulfide, these problems have become obstacles to its large-scale application. Therefore, this paper aims at the development of environmental friendly, simple process and efficient synthesis of cobalt sulfide on the electrode, the high conductivity material and composite to overcome the problem of low conductivity, and make the two play a synergistic catalytic effect to improve the catalytic properties of materials. In this paper the main research contents are as follows: the successful synthesis of 3D flowerlike cobalt sulfide by using organic molecules induced by the (Co S) explains the three hierarchical structure. The growth mechanism of dimensional hierarchical structure, and for the first time the 3D flower like Co S hierarchical structure as electrode materials into dye-sensitized solar cell field, studied its electrocatalytic properties and photovoltaic properties. The electrochemical tests show that for the reduction of I3 - Co S, 3D flowerlike hierarchical structure has good electrocatalytic activity, attributed to the a nano sheet structure hierarchical structure not only promoted the diffusion of the electrolyte, but also increases the surface area of the material and improve its catalytic activity. As a result, the 3D flower like Co S hierarchical structure on the electrode of dye-sensitized solar cell based on the efficiency and the platinum electrode device based on similar three-dimensional classification. Synthesis of sulfide cobalt coated with graphene composite porous spheres by one-step hydrothermal method (CSHPS-G) material, and through the electrochemical test of single component of the cobalt sulfide (Co S), graphene oxide reduction (RGO) Electrocatalytic activity and CSHPS-G. The results show that compared with the single component material, CSHPS-G composites exhibited better electrocatalytic performance, so that the device achieves high efficiency. This is because the porous structure of the composite electrolyte not only provides an effective diffusion channel, increase the active site catalytic reaction but, because of the coated graphene, in between the CoS ball creates a three-dimensional conductive network, make up for the Co S material has poor electrical conductivity also can effectively restrain the disadvantages of graphite under high temperature agglomeration. As a result, device CSHPS-G composite electrode based on the obtained efficiency is higher than that of platinum electrode. The use of layer self assembly with pyrolysis directly on the surface of FTO prepared graphene cobalt sulfide nanoparticles modified transparent thin film electrode (CSG). To avoid the routine preparation of electrode slurry mixing process, scraping too complex The process is more important. The film thickness can be controlled in the preparation of nanometer scale, and highly transparent, is expected to be applied to the field of transparent electronic devices. The electrochemical test showed that CSG of iodine electroreduction of interlayer oxidation has good electrocatalytic activity to test.J-V, CSG transparent electrode of the device performance of the photovoltaic properties similar to the corresponding Pt based devices. Based on the development of a self-assembly technique modified by ion and functionalized graphene with different charge characteristics, through electrostatic adsorption directly on FTO conductive substrate were functionalized graphene / cobalt sulfide composite films were prepared (CFG) electrode. This process not only avoid the use of polyelectrolyte and other auxiliary materials self-assembly process of conventional layers, but also the interaction of functionalized graphene surface functional groups and sulfide cobalt nanoparticles of cobalt sulfide nanoparticles promoted At the same time, the electrochemical performance of the composite thin film electrode is tested. The CFG electrode shows good electrocatalytic performance. Therefore, based on the CFG thin film electrode, the cell efficiency is similar to that of Pt based devices.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB332

【相似文献】