碳纳米材料与金属复合结构中空位缺陷产生和作用机制的理论研究
发布时间：2018-08-09 12:53
【摘要】：从上个世纪90年代开始,碳纳米材料就成为了很多前沿领域的研究热点,这主要归功于其独特的结构和优异的物理、化学性质。碳纳米材料主要包括零维的富勒烯、一维的碳纳米管和二维材料石墨烯等,由于其独特的几何结构特性,在当今新型功能材料、微纳电子学器件等高新领域有着非常广阔的应用前景。例如,在新能源的核电池领域,辐射损伤所致的电池效能和寿命降低一直是一个棘手的问题,美国研究者Liviu Popa-simil提出了基于碳纳米管和金属复合材料的核电池设计方案,来实现核能到电能的高效转换(设计转化效率高达50%),其设计中就是利用了碳纳米管的耐辐照特性。本文的研究工作,就是基于这样一个设计方案,采用分子动力学方法,进一步研究了多壁碳纳米管中包覆金属后,对整体耐辐照性能的影响。同时又考虑了辐照损伤所产生的单空位缺陷,对石墨烯与金属的复合材料的稳定性以及其中碳原子和金属原子结合强度的影响。首先基于分子动力学的方法,本文通过构建三层碳纳米管中包覆金属的模型,并在100eV-1000eV的能量范围内,模拟用碳原子轰击整个体系,得出了辐照后体系中产生的配位缺陷、完美结构缺陷(perfect structure defect,pst缺陷)[1]和溅射原子的数目,并统计了总的辐射损伤量,与同样体系中,没有金属内嵌的情况作了对比。结果表明,在三层碳纳米管中内嵌金属铜后,整个体系的辐射损伤量有明显降低,从而提高了整体的耐辐照性能,同时也验证了碳纳米管材料在核电池中应用的可行性。本文运用密度泛函理论,研究了单空位缺陷对石墨烯和金属复合材料中碳原子和镍原子结合强度的影响机理,探讨了不同位置的缺陷所产生的不同的作用。计算时,我们选择了与石墨烯晶格匹配最接近的金属镍,使得石墨烯在Ni(111)面上形成1×1的结构,构建了6层镍原子和一层石墨烯的4×4的模型。根据镍与单层石墨烯结合的相对位置,我们构建了四种不同的结构,并分别模拟了在其中引入单空位缺陷后,体系的结构变化,最终发现,缺陷的引入,增强了缺陷趋于的石墨烯层和第一层Ni的结合,进而使得整个体系更加稳定;不同的缺陷位置也有不同的影响,top位的缺陷比hollow位缺陷对二者结合的加强更加明显。综上所述,本论文基于分子动力学的方法,模拟研究了碳原子轰击碳纳米管包覆金属这个模型体系,初步获得了结构缺陷与辐射损伤量的变化关系。论文通过运用密度泛函理论,研究了单空位缺陷对石墨烯和金属复合材料中碳原子和镍原子结合强度的影响机理,探讨了不同位置缺陷所产生的作用差异性。这些研究结果可为今后进一步开展石墨烯与金属的界面结合研究提供一定的理论参考。基于目前的研究工作,未来可开展更加系统性的研究,如研究除铜和镍之外的金属原子与石墨烯材料的结合强度与缺陷的关系等。
[Abstract]:Since the 90s of last century, carbon nanomaterials have become a hot spot in many frontiers, mainly due to their unique structure and excellent physical and chemical properties. Carbon nanomaterials mainly include zero dimensional fullerenes, one-dimensional carbon nanotubes and two-dimensional material graphene, due to their unique geometric properties, in the case of their unique geometric properties. This new type of functional materials, micro nanoelectronics devices and other high-tech fields have a very broad application prospects. For example, in the field of new energy nuclear batteries, the reduction of battery efficiency and life caused by radiation damage has been a difficult problem. Liviu Popa-simil of the United States proposed nuclear power based on carbon nanotubes and metal composites. The design of the pool is designed to achieve an efficient conversion of nuclear energy to electrical energy (up to 50% of the design conversion efficiency). In its design, the radiation resistance of carbon nanotubes is used in the design. This paper is based on a design scheme, using molecular dynamics method to further study the overall resistance of multi wall carbon nanotubes after the coating of metal. The effects of radiation properties on the single vacancy caused by radiation damage, the stability of the composites of graphene and metal and the influence of the bond strength of carbon atoms and metal atoms are considered. First, based on the method of molecular dynamics, the model of coating metal in three layers of carbon nanotubes is constructed and in 100eV-100 In the energy range of 0eV, the whole system was bombarded with carbon atoms, and the coordination defects produced in the irradiated system, the number of perfect structural defects (perfect structure defect, PST defect) [1] and the sputtering atom were obtained, and the total radiation damage was calculated, and the results were compared with those in the same system, without metal inlay. The radiation damage of the whole system is reduced obviously in the three layer carbon nanotubes, and the radiation resistance of the whole system is improved. At the same time, the feasibility of the application of the carbon nanotube materials in the nuclear battery is also verified. The influence mechanism of the bond strength of the nickel atom is discussed, and the different functions of the defects at different positions are discussed. In the calculation, we choose the closest metal nickel with the graphene lattice, making the graphene formed 1 x 1 Structure on the Ni (111) surface and constructing the 4 * 4 model of the 6 layer nickel atom and the one layer of graphene. In the relative position of the binding, we constructed four different structures, and simulated the structural changes of the system after the introduction of single vacancy defects. Finally, it was found that the introduction of the defects enhanced the binding of the graphene layer and the first layer of Ni, which made the whole system more stable, and different defect positions were different. As a result, the defect of the top bit is more obvious than that of the two. To sum up, based on the method of molecular dynamics, this paper simulated the model system of carbon nanotube cladding metal by carbon atom bombardment, and preliminarily obtained the relationship between the structural defects and the change of radiation damage. The effect of single vacancy on the bonding strength of carbon atoms and nickel atoms in graphene and metal composites is studied. The differences in the effect of defects in different positions are discussed. These results can provide some theoretical reference for further development of the interface of graphene and metal. In the future, more systematic research can be carried out, such as the relationship between the binding strength of metal atoms and Shi Moxi materials except for copper and nickel.
【学位授予单位】：中国科学院研究生院(上海应用物理研究所)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;O613.71
本文编号：2174135
[Abstract]:Since the 90s of last century, carbon nanomaterials have become a hot spot in many frontiers, mainly due to their unique structure and excellent physical and chemical properties. Carbon nanomaterials mainly include zero dimensional fullerenes, one-dimensional carbon nanotubes and two-dimensional material graphene, due to their unique geometric properties, in the case of their unique geometric properties. This new type of functional materials, micro nanoelectronics devices and other high-tech fields have a very broad application prospects. For example, in the field of new energy nuclear batteries, the reduction of battery efficiency and life caused by radiation damage has been a difficult problem. Liviu Popa-simil of the United States proposed nuclear power based on carbon nanotubes and metal composites. The design of the pool is designed to achieve an efficient conversion of nuclear energy to electrical energy (up to 50% of the design conversion efficiency). In its design, the radiation resistance of carbon nanotubes is used in the design. This paper is based on a design scheme, using molecular dynamics method to further study the overall resistance of multi wall carbon nanotubes after the coating of metal. The effects of radiation properties on the single vacancy caused by radiation damage, the stability of the composites of graphene and metal and the influence of the bond strength of carbon atoms and metal atoms are considered. First, based on the method of molecular dynamics, the model of coating metal in three layers of carbon nanotubes is constructed and in 100eV-100 In the energy range of 0eV, the whole system was bombarded with carbon atoms, and the coordination defects produced in the irradiated system, the number of perfect structural defects (perfect structure defect, PST defect) [1] and the sputtering atom were obtained, and the total radiation damage was calculated, and the results were compared with those in the same system, without metal inlay. The radiation damage of the whole system is reduced obviously in the three layer carbon nanotubes, and the radiation resistance of the whole system is improved. At the same time, the feasibility of the application of the carbon nanotube materials in the nuclear battery is also verified. The influence mechanism of the bond strength of the nickel atom is discussed, and the different functions of the defects at different positions are discussed. In the calculation, we choose the closest metal nickel with the graphene lattice, making the graphene formed 1 x 1 Structure on the Ni (111) surface and constructing the 4 * 4 model of the 6 layer nickel atom and the one layer of graphene. In the relative position of the binding, we constructed four different structures, and simulated the structural changes of the system after the introduction of single vacancy defects. Finally, it was found that the introduction of the defects enhanced the binding of the graphene layer and the first layer of Ni, which made the whole system more stable, and different defect positions were different. As a result, the defect of the top bit is more obvious than that of the two. To sum up, based on the method of molecular dynamics, this paper simulated the model system of carbon nanotube cladding metal by carbon atom bombardment, and preliminarily obtained the relationship between the structural defects and the change of radiation damage. The effect of single vacancy on the bonding strength of carbon atoms and nickel atoms in graphene and metal composites is studied. The differences in the effect of defects in different positions are discussed. These results can provide some theoretical reference for further development of the interface of graphene and metal. In the future, more systematic research can be carried out, such as the relationship between the binding strength of metal atoms and Shi Moxi materials except for copper and nickel.
【学位授予单位】：中国科学院研究生院(上海应用物理研究所)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;O613.71
【参考文献】
相关期刊论文 前1条
1 宋虎;杨文宁;周晓松;罗顺忠;彭汝芳;;富勒烯~(60)Co γ辐照的稳定性研究[J];辐射研究与辐射工艺学报;2011年01期
，本文编号：2174135
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