掺杂、缺陷修饰石墨烯吸附性能的第一性原理研究

论文总字数：26917字

目 录

一、 绪论 6

1.1石墨烯的研究背景 6

1.2石墨烯的基本结构 6

1.3石墨烯的性质 10

1.3.1力学性质 10

1.3.2热学性质 10

1.3.3电学性质 11

1.4石墨烯的吸附性能 11

二、理论及计算方法 12

2.1第一性原理 12

2.2 密度泛函理论 12

2.2.1两大近似 12

2.2.2 Hohenberg-Kohn定理 13

2.3 相关软件介绍 17

三、本征石墨烯的吸附性能 18

3.1 引言 18

3.2构建模型和计算方法 18

3.3结果分析 18

四、 掺杂石墨烯的吸附性能 21

4.1 引言 21

4.2 构建模型和计算方法 21

五、 缺陷石墨烯的吸附性能 24

5.1引言 24

5.2构建模型和计算方法 24

5.3结果分析 26

六、 总结与展望 29

致谢 30

参考文献 31

掺杂、缺陷修饰石墨烯吸附性能的第一性原理研究

叶晨钰

，China

Abstract：In recent years, the study of graphene has received more and more attention, mainly due to the superior structure and performance of graphene. Graphene is widely used in today's physical electronics, optics, and sensor devices. Among them, graphene has become an ideal adsorbent material due to its large specific surface area, high electron transfer rate, and good thermal stability.

In this paper, we have calculated the adsorption energy, density of states, and energy band structure of intrinsic graphene, doped graphene and defect graphene. In the process, the CASTEP software package in the Material Studio software was used to establish the model. The adsorption of NH3 molecules on the intrinsic structure, single-vacancy defects, and double-vacancy defects and topological defects of Graphene, as well as, graphenes doped with Al atoms, Pb atoms and Li atoms were systematically studied. Graphene NH3 molecule structure.

The full text consists of six chapters. The first chapter is a brief introduction to graphene. The first is the development status of graphene and some research prospects at home and abroad, followed by a brief analysis of the crystal structure of the graphene material. Finally, graphite is introduced, the properties of graphene, include its mechanical, thermal and electrical properties as well as the adsorption properties of graphene.

The second chapter analyzes the principle and the method of the calculation, and introduces the related points of the first-principles and density functional theory. The density functional theory includes adiabatic approximation, Hartree-Fock self-consistent field approximation, Hohenberg-Kohn theorem and Kohn-Sham equation. Finally, it briefly introduces the model solution software Material Studio and the CASTEP software package in this article.

In the third chapter, the model was solved, and the performance of NH3 molecule and the pollution it brought about were briefly analyzed, which led to the important application of graphene as a sensor. The third chapter studies the adsorption energy of intrinsic graphene, and the energy obtained is 0.28 eV. Due to the stable structure of graphene, the adsorption of NH3 molecule is physical, and the adsorption energy is not high.

In the fourth chapter, based on the third chapter, we study the influence of the introduction of impurity atoms on the intrinsic stable structure of graphene and its effect on the adsorption energy. In this paper, Al atoms, Pb atoms and Li atoms were selected for doping. The corresponding adsorption energy is 1.32 eV, 1.08 eV, and 4.43 eV. From the results, it can be seen that when graphene is doped with metal atoms, its adsorption energy is greatly improved, especially the adsorption energy of Li atoms.

The fifth chapter is also based on the third chapter, which studies the adsorption model of NH₃ on the defect graphene. Three models of single vacancy defects, double vacancy defects and topological defects are selected. The obtained adsorption energies were 0.40 eV, 1.19 eV, and 1.82 eV, respectively, and the adsorption energy also improved to some extent compared to the intrinsic graphene, and the more the graphene structure deformed, the higher the adsorption energy.

Chapter 6 summarizes this article and looks forward to future research.

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