| Summary: | 碩士 === 國立中正大學 === 化學暨生物化學研究所 === 105 === The purpose of this research is to find a self-assembled monolayer system to modify gold surface and maximize the change in its work function, so as to facilitate charge injection in organic electronic devices when using the metal as electrode. The change of work function relates to the dipole moment of the molecule used to modify the electrode surface along the surface normal. However, the CF3SO2BnCH2SH (dipole : 6.52 debye) -modified Au has lower work function(work function : 5.33 eV) than CF3BnCH2SH(dipole : 3.99 debye) -modified Au (work function : 5.81 eV). It is presumed that with higher dipole of molecule, there is stronger electrostatic repulsion between molecules so that either a closely-packed monolayer cannot be formed or the direction of the dipole is pushed away from the normal of the surface.
To reduce the repulsion, two methods are proposed. One is to use mixed monolayer containing molecules with the same terminal functional group but with different molecular length. The other is to improve the intermolecular attractions in a mixed layer with electron-poor and electron-rich arenes. In specific mixing ratios, both methods can achieve a work function higher than what a single component monolayer can achieve. It is worth noting that in the former one, the adsorption density of mixed monolayer is ~10% more than single component monolayer by cyclic voltammetry and X-ray photon spectrum.
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