石墨烯优化改性的染料敏化太阳能电池的研究

发布时间：2018-10-08 16:37

【摘要】：在“绿色环保”理念的引领和“能源危机”现实的推动下,染料敏化太阳能电池因其制备工艺简单、成本低廉、能量回报率高、无毒等优点广受科学研究者们的青睐。此外,二维碳系材料石墨烯也引起了科学界极大的研究兴趣。利用石墨烯的良好导电性和大的比表面积等优点,以及石墨烯量子点特殊的光学性质和能带结构,将它们分别应用到染料敏化太阳能电池中,制备石墨烯材料优化的染料敏化太阳能电池已逐渐成为本领域研究热点之一。本论文从材料制备入手,具体展开了以下研究内容并取得了相关成果： (1)石墨烯-P25复合光阳极的制备。利用简单的球磨法,以石墨烯氧化物(GO)和商业二氧化钛(P25)为原料,摸索了GO与P25的最佳比例,制备出了性能优异的石墨烯-P25复合光阳极薄膜,并将其应用到染料敏化太阳能电池中,制备出了性能明显提高的染料敏化太阳能电池。与纯P25染料敏化太阳能电池相比,以石墨烯-P25复合薄膜为光阳极的电池的光电转效率提高了20%。该种石墨烯的引入导致P25基染料敏化太阳能电池的性能得以提高,主要归因于GO退火引起薄膜比表面积的增大以及石墨烯自身良好的导电性。此外,由于DSSC光电性能的提高与金红石含量增加的变化规律的一致性,表明金红石相含量的适度增加有利于光阳极内光的反射和吸收及电池光电性能的提高。 (2)石墨烯-Ti02复合光阳极的制备及其DSSC性能的提高。利用水热法制备了一系列不同石墨烯掺杂含量的Ti02光阳极。研究了不同的石墨烯掺杂量对电池结构和性能的影响,制备出了性能最优的石墨烯掺杂Ti02光阳极膜及其电池。研究表明,石墨烯掺杂能显著影响该Ti02膜的表面形貌,增加该膜的染料吸附量,提高了所制备电池的开路电压、短路电流密度和光电转换效率。并且,在最佳的石墨烯掺杂样品中获得了电池的光电转换效率为7.02%,显著(28.6%)高于未掺杂的样品。我们初步认为石墨烯掺杂导致的电池性能的改善主要是因为薄膜比表面积的提高导致染料吸附量的增加以及石墨烯的良好导电性。 (3)石墨烯量子点优化的Ti02光阳极的制备及其在染料敏化太阳能电池中的应用。石墨烯量子点具有优越的光学特性,本研究首次成功地制备了GQDs辅助敏化的Ti02光阳极及其DSSCs。Raman谱和TEM观测证实了GQDs的特性。研究表明,光阳极的染料吸附量随GQDs负载量的增加呈先降低后增加的规律,而对应的DSSCs的短路电流Jsc、开路电压Voc及光电转换效率η呈现先增加后降低的规律。GQDs优化的最佳的DSSC的Jsc和n为14.07±0.02mA/cm2及6.10±0.01%,比传统的DSSC的Jsc和η分别提高了约30.9%和19.6%。这些DSSCs性能的改善主要归因于GQDs优良的光敏响应及其对TiO2的热电子注入效应。此研究表明GQDs不仅可改善DSSC的性能,还可在一定程度上减少染料的使用,具有经济和环保的重要意义。
[Abstract]:Under the guidance of the idea of "green environment" and the reality of "energy crisis", dye sensitized solar cells are favored by scientific researchers for their advantages of simple preparation process, low cost, high energy return rate and non-toxicity. In addition, graphene, a two-dimensional carbon-based material, has attracted great interest from the scientific community. Based on the advantages of good electrical conductivity and large specific surface area of graphene, as well as the special optical properties and band structure of graphene quantum dots, they are applied to dyestuff sensitized solar cells, respectively. Dye-sensitized solar cells with optimized graphene materials have become one of the research hotspots in this field. In this thesis, the following research contents are carried out: (1) preparation of graphene-P25 composite photoanode. The graphene P25 composite photoanode thin films with excellent properties were prepared by a simple ball milling method using graphene oxide (GO) and commercial titanium dioxide (P25) as raw materials, and the optimum ratio of GO to P25 was explored. It was applied to dye sensitized solar cells, and the dye sensitized solar cells with better performance were prepared. Compared with pure P25 dye sensitized solar cells, the photoconversion efficiency of the cells with graphene P25 composite film as the photoanode was increased by 20%. The introduction of graphene improved the performance of P25-based dye sensitized solar cells, which was mainly attributed to the increase of the specific surface area of the films caused by GO annealing and the good electrical conductivity of graphene itself. In addition, the increase of DSSC photoelectric property is consistent with the increase of rutile content, which indicates that the moderate increase of rutile phase content is beneficial to the light reflection and absorption in the photoanode and the improvement of the photovoltaic performance of the cell. (2) preparation of graphene-Ti02 composite photoanode and improvement of its DSSC properties. A series of Ti02 photoanodes with different graphene content were prepared by hydrothermal method. The effect of different amount of graphene doping on the structure and properties of the battery was studied. The graphene doped Ti02 photoanode film and its cell were prepared. The results show that graphene doping can significantly affect the surface morphology of the Ti02 film, increase the amount of dye adsorption, and improve the open circuit voltage, short circuit current density and photoelectric conversion efficiency of the prepared battery. In addition, the photovoltaic conversion efficiency of the battery was 7.022 in the best graphene doped sample, which was significantly higher than that of the undoped sample (28.6%). We preliminarily believe that the improvement of cell performance caused by graphene doping is mainly due to the increase of the specific surface area of the film and the increase of the dye adsorption capacity and the good conductivity of graphene. (3) preparation of Ti02 photoanode optimized by graphene quantum dots and its application in dye sensitized solar cells. Graphene quantum dots (QDs) have excellent optical properties. In this study, GQDs assisted sensitized Ti02 photoanodes and their DSSCs.Raman spectra and TEM measurements have been successfully prepared for the first time to confirm the properties of GQDs. The results show that the dye adsorption capacity of photoanode decreases first and then increases with the increase of GQDs loading. The corresponding short-circuit current Jsc, open-circuit voltage Voc and photoelectric conversion efficiency 畏 of DSSCs are increased first and then decreased. The Jsc and n of the optimized DSSC are 14.07 卤0.02mA/cm2 and 6.10 卤0.01, which are 30.9% and 19.6% higher than that of the traditional DSSC Jsc and 畏, respectively. The improvement of DSSCs performance is mainly due to the excellent Guang Min response of GQDs and its hot electron injection effect on TiO2. This study shows that GQDs can not only improve the performance of DSSC, but also reduce the use of dyes to a certain extent.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM914.4

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