Rubrene/TPD表面及其界面的AFM和XPS研究

Surface and interface analysis of Rubrene/TPD using AFM and XPS

在indium-tin-oxide(ITO)玻璃上采用多源蒸发的方法制备了红荧烯(Rubrene)/TPD样品。由原子力显微镜(AFM)得到的表面形貌图显示Rubrene膜具有良好的均匀性。利用X射线光电子能谱仪(XPS)研究了两种材料表面和界面的电子态。由Rubrene/TPD的表面分析可知,C1s精细谱中有3个峰最强的峰是由氧化造成的,而不是对应于芳香碳(284.55eV)。空气中的O2和H2O扩散到样品里形成O1s峰。用氩离子束溅射剥蚀表面,随着时间的增长,芳香碳对应的峰越来越强,282.45和289.62eV处的峰则迅速消失,当溅射时间超过4920s时,在2847eV处引入了一个新的峰,对应于C—N键。O1s峰迅速减弱是因为氧沾污的去除。N1s谱中的N—C键缓慢增强,到达界面附近时峰的强度变得稳定。C1sN1s和O1s谱中都有峰发生化学位移。

The Rubrene/TPD sample is prepared by using multiple source evaporation on the ITO coated glass.The surface topography obtained by using AFM indicates that the Rubrene film has excellent evenly distribution.The electronic states of the surface and interface of Rubrene/TPD are investigated by using XPS.From the surface analysis,it is obtained that there are three peaks in the fine spectra of C1s.The main peak is formed not by C—C bond but by the oxidation of C.With the increasing of sputtering time,the peak corresponding to the aromatic C becomes stronger and stronger but the other two peaks disappear swiftly.The O1 speaks are weakened because of the removal of the oxygen contamination.The N—C bond strengthens slowly in the N1s spectrum.The N1speak＇s intensity becomes stable when it comes to the interface.The peak corresponding to the aromatic C has a chemical shift of 0.25eV and a chemical shift of 0.2eV is found at the peak corresponding to the N—C bond.The peak formed by O contamination has the biggest shift.