石墨烯透明导电薄膜的制备和表征

发布时间：2018-05-15 00:38

本文选题：氧化石墨烯 + 石墨烯　；参考：《北京交通大学》2017年硕士论文

【摘要】：石墨烯作为单原子层厚度的二维新型材料,具有比表面积大、电子迁移率高、机械强度好、高透光率等一系列性质,因此它可能是取代氧化铟锡(ITO)作为电极的材料,同时,在储能、半导体、光电子器件、能源材料等领域也体现出巨大应用前景。因此需要开发新颖和简单的方法用于大规模制备具有高导电性和高透明度的石墨烯薄膜。本文采用Hummers法获得氧化石墨烯(GO),通过旋涂成膜得到GO薄膜;并使用SnC12界面缩减还原方法获得rGO薄膜,探究其还原效果以及影响薄膜性能的各种因素;并进一步探究利用CNTs和GO的混合液制备透明导电薄膜。所得成果概括如下:(1)通过SnCl_2界面缩减方法可在不同尺寸和材质的基底制备石墨烯薄膜。探究了影响石墨烯薄膜性能的各种因素,确定最佳转速是100Or/min;最佳还原剂浓度是 1.5 M;得到 GO 浓度为 2 mg/ml 时,在 550 nm 处,T=80%,Rs=10.5 kΩ/sq的石墨烯薄膜。相比VC还原,XRD图表明SnC12还原方法对应rGO层间距更小,还原性更强;Raman表征结果表明SnC12还原的薄膜I2D/ID+G更大,还原效果更显著;由FT-IR图可知,这是由于SnC12方式对GO中含氧官能团的还原更彻底;相同透光率下,SnC12还原的薄膜方阻比VC还原平均减少约20kΩ/sq,这说明薄膜还原越彻底,薄膜二维晶格结构恢复越好,电子传输能力更强。(2)对比一次还原(SnC12)与二次还原(SnC12+VC),Raman图谱表明,二次还原I2D/ID+G更大,因此二次还原的还原性要强于一次还原;对应XRD衍射图中二次还原特征峰位相对于一次还原发生右移,二次还原对应rGO的层间距更小,即二次还原的还原性强于一次还原;由FT-IR图可知,这主要是因为二次还原能够除去的含氧官能团的种类更多、更彻底。此外,二次还原薄膜相比一次还原方阻更小,其结果也证实二次还原的效果更显著;相同透光率下,二次还原得到的薄膜方阻平均减小约3 kΩ/sq。(3)CNTs/石墨烯导电薄膜制备过程中,少量CTAB对CNTs进行修饰,可减轻其易团聚和不易分散的特性。得到能够改善导电薄膜导电性能的最佳配比,即等体积的CNTs浓度:GO浓度=1:8;前驱体分散液浓度小于3 mg/ml时,复合薄膜导电性的改善显著,平均方阻下降2 kΩ/sq;CNTs/石墨烯导电薄膜中,石墨烯片层能够填补CNTs组成的导电网络的空隙,为载流子的迁移提供更多通道,因此可以改善石墨烯薄膜导电性能。
[Abstract]:Graphene, as a new two-dimensional material with monatomic layer thickness, has a series of properties, such as large specific surface area, high electron mobility, good mechanical strength, high transmittance and so on. Therefore, graphene may replace indium tin oxide (ITO) as electrode material, at the same time, Energy storage, semiconductors, optoelectronic devices, energy materials and other fields also show great application prospects. Therefore, novel and simple methods need to be developed for large-scale preparation of graphene thin films with high conductivity and transparency. In this paper, go thin films are obtained by Hummers method, go films are obtained by spin coating, and rGO thin films are obtained by SnC12 interface reduction method, and the reduction effect and various factors affecting the properties of the films are investigated. The transparent conductive films were prepared by using the mixture of CNTs and go. The results are summarized as follows: (1) graphene thin films can be prepared on substrates of different sizes and materials by SnCl_2 interface reduction. Various factors affecting the properties of graphene thin films were investigated. The optimum rotational speed was 100Orr / min, the optimum concentration of reductant was 1.5m, and the graphene films with 2 mg/ml go concentration were obtained at 550 nm. Compared with VC reductive X-ray diffraction diagram, the SnC12 reduction method shows that the rGO layer spacing is smaller and the reductive property is stronger. The results show that the I2D/ID G of the SnC12 reduced film is larger and the reduction effect is more significant than that of the SnC12 reduction method, and the results can be seen from the FT-IR diagram. This is due to the fact that the reduction of oxygen functional groups in go by SnC12 method is more thorough, and that the square resistance of thin films reduced by SnC12 at the same transmittance is about 20k 惟 / sqm compared with VC reduction, which indicates that the more thorough the reduction of the thin films, the better the two-dimensional lattice structure of the films is restored. The results show that the second reduction I2D/ID G is larger than the second reduction I2D/ID G, so the reducibility of the secondary reduction is stronger than that of the primary reduction. In the corresponding XRD diffraction pattern, the peak position of the secondary reduction is shifted to the right, and the interval between the layers of the secondary reduction corresponding to the rGO is smaller, that is, the reducibility of the secondary reduction is stronger than that of the first reduction. This is mainly due to the second reduction can remove more types of oxygen-containing functional groups, more thorough. In addition, the second reduction film has a smaller square resistance than that of the first reduction, and the results show that the second reduction is more effective, and at the same light transmittance, the square resistance of the second reduction film is reduced by about 3 k 惟 / sq.3C / graphene in the preparation process of CNTsS / graphene conductive thin films. A small amount of CTAB modifies CNTs to reduce its agglomeration and dispersion. The optimum ratio of the conductive properties of the conductive thin films was obtained, that is, when the concentration of CNTs was equal to 1: 8, the concentration of precursor dispersion was less than 3 mg/ml, the conductivity of the composite films was improved significantly, and the average square resistance was decreased by 2 k 惟 / sqnn / graphene conductive thin films. The graphene layer can fill the gap of the conductive network formed by CNTs and provide more channels for carrier migration, so it can improve the conductivity of graphene film.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TB383.2

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