OPE和PBM分子在石墨表面自组装结构的STM研究
发布时间：2018-12-15 07:20
【摘要】：本论文利用扫描隧道显微技术(STM)为主要研究手段,结合密度泛函理论计算(DFT)研究了两种有机化合物在石墨表面的吸附行为,提出了通过客体分子的浓度调控组装结构的研究新思路。选取两组功能化合物体系,研究了其表面的吸附行为,总结分子在表面组装特点和规律。主要研究结果如下:一、利用STM技术与DFT计算相结合,研究了一系列不同长度的骨架和侧链的低聚芳撑乙炔分子(OPE)分子在石墨表面的自组装结构。研究发现,这些低聚物根据它们的化学结构的不同可以形成不同的自组装结构,其中两个分子间侧链形成的分子间相互作用的不同是主要影响因素。这些组装的结构通过两分子之间的侧链交叉以及分子和HOPG底物之间形成的范德华力结合在一起。这些研究将在功能性共轭分子的设计和应用中提供重要的指导。二、利用STM研究了两种共轭芳香大环分子(PBM)在石墨表面的自组装。主要探究了主体分子的大小,形状和客体分子的浓度对PBMs/COR主-客体系统自组装的影响。STM图像显示PBM1(主体部分为三角形)分子呈现规则的线性网络结构,而PBM2(主体部分为四边形)分子形成了有序的纳米孔网络结构。当引入客体分子COR分子时,PBM1的自组装结构保持不变,而PBM2分子则可以与客体分子形成主客体组装结构。此外,随着客体分子COR浓度的增加,PBM2/COR组装结构发生变化。借助密度泛函理论计算,发现在引入COR客体分子后,尺寸匹配和浓度依赖效应在PBM2主机网络的结构转换中起着重要的作用。该工作将有助于我们深入了解表面上自组装和控制分子图形形成的动态过程。
[Abstract]:In this paper, the adsorption behavior of two organic compounds on graphite surface was studied by means of scanning tunneling microscopy (STM) and density functional theory (DFT). A new way to study the assembly structure by the concentration regulation of guest molecules is proposed. The adsorption behavior of two groups of functional compounds on the surface was studied, and the characteristics and rules of molecular assembly on the surface were summarized. The main results are as follows: firstly, the self-assembly structure of a series of (OPE) molecules with different lengths of skeleton and side chain on graphite surface has been studied by using STM technique and DFT calculation. It is found that these oligomers can form different self-assembled structures according to their different chemical structures, in which the intermolecular interactions formed by the side chains between two molecules are the main influencing factors. These assembled structures are bound by the side chain crossing between the two molecules and the van der Waals force formed between the molecule and the HOPG substrate. These studies will provide important guidance in the design and application of functional conjugated molecules. Secondly, STM was used to study the self-assembly of two conjugated aromatic macrocyclic molecules (PBM) on graphite surface. The effects of the size, shape and concentration of host molecule on the self-assembly of host guest system of PBMs/COR are studied. STM images show the linear network structure of PBM1 (the host part is triangular). However, PBM2 (quadrilateral) molecules form an ordered network structure of nano-pores. When the guest molecule COR molecule is introduced, the self-assembly structure of PBM1 remains unchanged, while the PBM2 molecule can form the host-guest assembly structure with the guest molecule. In addition, the PBM2/COR assembly structure changes with the increase of the concentration of guest molecule COR. Based on density functional theory (DFT), it is found that the size matching and concentration dependent effects play an important role in the structural transformation of PBM2 host networks after the introduction of COR guest molecules. This work will help us to understand the dynamic process of surface self-assembly and controlling the formation of molecular patterns.
【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】：O647.31
本文编号：2380236
[Abstract]:In this paper, the adsorption behavior of two organic compounds on graphite surface was studied by means of scanning tunneling microscopy (STM) and density functional theory (DFT). A new way to study the assembly structure by the concentration regulation of guest molecules is proposed. The adsorption behavior of two groups of functional compounds on the surface was studied, and the characteristics and rules of molecular assembly on the surface were summarized. The main results are as follows: firstly, the self-assembly structure of a series of (OPE) molecules with different lengths of skeleton and side chain on graphite surface has been studied by using STM technique and DFT calculation. It is found that these oligomers can form different self-assembled structures according to their different chemical structures, in which the intermolecular interactions formed by the side chains between two molecules are the main influencing factors. These assembled structures are bound by the side chain crossing between the two molecules and the van der Waals force formed between the molecule and the HOPG substrate. These studies will provide important guidance in the design and application of functional conjugated molecules. Secondly, STM was used to study the self-assembly of two conjugated aromatic macrocyclic molecules (PBM) on graphite surface. The effects of the size, shape and concentration of host molecule on the self-assembly of host guest system of PBMs/COR are studied. STM images show the linear network structure of PBM1 (the host part is triangular). However, PBM2 (quadrilateral) molecules form an ordered network structure of nano-pores. When the guest molecule COR molecule is introduced, the self-assembly structure of PBM1 remains unchanged, while the PBM2 molecule can form the host-guest assembly structure with the guest molecule. In addition, the PBM2/COR assembly structure changes with the increase of the concentration of guest molecule COR. Based on density functional theory (DFT), it is found that the size matching and concentration dependent effects play an important role in the structural transformation of PBM2 host networks after the introduction of COR guest molecules. This work will help us to understand the dynamic process of surface self-assembly and controlling the formation of molecular patterns.
【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】：O647.31
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