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结合紫外光电子能谱(UPS),X射线光电子能谱(XPS),原子力显微镜(AFM)和掠入射X射线衍射谱(GIXRD)等实验手段,系统研究了2,7-二辛基[1]苯并噻吩并[3,2-b]苯并噻吩在Cu(100)基底上的吸附、生长过程以及界面能级结构.发现第一层的分子平躺吸附于Cu(100)上形成稳定的物理吸附.随膜厚增加,分子取向转为直立于薄膜平面,生长模式转为岛状生长模式.分子取向的变化导致膜厚大于16A的薄膜的能级结构发生变化.直立取向的分子在表面形成由内向外的电偶极层,引起真空能级下降,功函数降低;而轨道电离的各向异性使得分子从平躺到直立时UPS得到的分子最高占据轨道(HOMO)峰型发生变化,且HOMO起始边向深结合能端移动整体上随着膜厚的增加,真空能级向下弯曲,HOMO下移,电离能则先减小后增大下移的能带结构利于电子从界面向表面的迁移以及空穴从表面向界面的迁移.
In this paper, 2,7-dioctyl [1] was systematically studied by means of UV-Vis, X-ray photoelectron spectroscopy, atomic force microscopy and grazing incidence X-ray diffraction. The adsorption, growth and interfacial energy structure of benzothieno [3,2-b] benzothiophene on Cu (100) substrate were observed. The first layer of molecule was found to be adsorbed on Cu (100) Physical adsorption.With the increase of film thickness, the molecular orientation turned upright on the plane of the film, and the growth mode turned into island growth mode.The change of molecular orientation led to the change of the energy level structure of the film with the film thickness greater than 16 A. The orientation of the molecules on the surface The electric dipole layer is formed from the inside to the outside, causing the vacuum energy level to drop and the work function to decrease. The anisotropy of orbital ionization makes the HOMO peak shape of the molecule change from lying to standing, As the thickness of the HOMO increases, the vacuum energy level will bend downward. When the HOMO moves downward, the ionization energy decreases and then increases. The energy band structure that moves downwards is conducive to the electron from the interface Migration to the surface and migration of holes from the surface to the interface.