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在金(111)表面组装了具有不同末端基团的硫醇单层分子膜,并利用导电原子力显微镜研究了分子膜的电输运性质,发现不同末端基团的分子自组装膜的导电能力有明显差别.结合X射线光电子能谱,研究了末端基团中碳原子的结合能与相应硫醇分子电导的关系.结果表明不同末端基团分子膜导电能力的差别可归结为末端基团碳原子电子结合能的差异.结合能越高,末端基团电子的局域化程度越强,导致电子有效注入分子主链的势垒越高,从而减弱了分子膜对电子的输运能力.此外,实验还发现不同末端基团的硫醇单层分子膜有不同的表面电势,导致分子膜电流电压特性曲线的零点产生偏离.
The thiol monolayers with different terminal groups were assembled on the surface of gold (111), and the electrical transport properties of the molecular films were studied by means of conductive atomic force microscopy. It was found that the conductivity of the molecular self-assembled films with different terminal groups was Obvious difference.Combined with X-ray photoelectron spectroscopy, the relationship between the binding energy of the carbon atoms in the terminal groups and the corresponding conductance of the thiol molecules was studied.The results show that the difference of the conductivity of the molecular films of different terminal groups can be attributed to the terminal carbon atoms The higher the binding energy is, the stronger the degree of localization of the terminal group electrons, leading to the higher barrier of the electron injection into the main chain of the molecule and the weaker electron transport ability of the molecular film.In addition, It was also found that the thiol monolayer films with different terminal groups have different surface potentials, which leads to the deviation of the zero point of the molecular film current-voltage characteristic curve.