STM Study Of A Self-Assembly Behavior Of Phthalocyanine And Bromic Long Chain Alkanes On HOPG

The development of nanoscience and nanotechnology in future is determined on how to obtain nanostructures. Molecular self-assembly is an effective method fabricating molecular nanostructure. A lot of molecular assembly systems are interface adsorption systems, especially solid interface adsorption systems. The study of molecular interface self-assembly behavior is very important to understand the formation regular of molecular nanostructure and to further realize the artificial control of molecular nanostructure. Scanning tunneling microscopy (STM) has emerged as a powerful tool to investigate molecular interface assembly behavior. At present, the STM study of interfacial adsorption assembly structure involves mainly the investigation of single-component systems, however, it is necessary to study multi-component systems for fabricating the functional devices.In this thesis, the self-assembly behavior of pathalocyanine and bromic long-chain alkanes molecular on highly oriented pyrolytic graphite (HOPG) has been investigate by STM, and the obtained nanostructure has been further analyzed.Part one REVIEWChapter one The nanostructure and its preparation technologyIn this chapter, the fundamental conception, preparation technology of nanostructure, and classify of nanostructure system were reviewed.Chapter two Self-assembly technologyThe self-assembly technology and molecule self-assembly were introduced simply in this chapter, and some self-assembly films from the aspects of main character, classify, influence factors, application, and prospects were also reviewed.Chapter three Scanning tunnel microscopeThe theoretical thereunder, technical achievement, advantage, application, and up-to-date evolution of STM were summarized.Part two EXPERIMENTSChapter one STM study of a self-assembly behavior of phthalocyanine and 1-bromohexadecane on HOPGThe self-assembly behavior of phthalocyanine (Pc) and 1-bromohexadecane (C16Br) is studied by STM. Binary mixtures of different molar ratio are also observed, such as 1:1, 1:2, 1:3, 1:3.5, 1:4, and 1:5. By adjusting the molar ratio of Pc to C16Br to about 1:3-1:4, the resulting high stability and the well ordered assembly can be obtained easily on the HOPG surface. Interaction of C16Br with Pc is intermolecular, not covalent, which is tested by the solution of AgNO3. It is crucial to make the solvent of the sample to be volatilized completely, so that the assembly structure can be observed more stably.Chapter twe STM study of a self-assembly behavior of phthalocyanine and 1-bromododecane on HOPGThe self-assembly behavior of phthalacyanine (Pc) and 1-bromododecane (C12Br) is studied by STM. Binary mixtures of different molar ratio are also observed, such as 1:3, 1:6, 1:9 and 1:12. By adjusting the molar ratio of Pc to C12Br to about 1:3—1:6, the resulting high stability and the ordered assembly structure can be obtained easily on the HOPG surface. Interaction of C12Br with Pc is intermolecular, not covalent, which is tested by the solution of AgNO3. The analysis of assembly structure of Pc and C12Br results that it is easy to obtain ordered structure and multi-layer structure.Chapter three ConclusionThe chapter concludes relative conclusions of the self-assembly behavior of pathalocyanine and bromic long-chain alkanes molecular on HOPG. Interaction of Pc with bromic long-chain alkanes and the reasons of deference between theory and experiment are analyzed. The further study of multi-component interface assembly system will be more potential.