Structure of self-assembled monolayer of decanethiol and C60 on Au(111) studied by scanning tunnelling microscope

Xia, Chunqiu (2024). Structure of self-assembled monolayer of decanethiol and C60 on Au(111) studied by scanning tunnelling microscope. University of Birmingham. Ph.D.

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Abstract

This thesis presents the structure of decanethiol and C60 on Au(111) observed by scanning tunnelling microscope (STM). STM is a real space imaging technique with resolution high enough to directly view atoms and molecules.
Gold is a noble metal providing a large flat surface on its (111) for growing selfassembled monolayer of thiols and fullerenes, both of which would exhibit regular phases with long range order on Au(111) as studied previously. I choose decanethiol as an example of long chain thiols to mix with C60 and observe their structure on Au(111) by STM.
The interaction between decanethiol and C60 is of mainly Van der Waals in nature. This is in contrast to most of the biocomponent systems reported. The lack of directional bonding the two molecules favours the formation of a range of structures.
The mixture exhibits many different phases: sheer stripped phase of decanethiols, regular phases of thiol-C60, heptamers of C60, intermediate phase and irregular phase. Different phases provide various types of information. Regular phases and heptamers can be used to construct models to identify the positions of decanethiols and C60 molecules. For the irregular phases, I have performed some statistics analysis and found the average molecule-molecule distance. Intermediates, which exhibit semi-regular structures, provide a series of images about the motion of C60 and can be used to identify the how the molecules from the irregular regions get incorporated into the regular phase.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):