【摘要】 用原子力显微镜(AFM)研究了LiBq4/ITO样品表面形貌,结果表明LiBq4层中存在很多裂缝和空隙。用X射线光电子谱(XPS)研究样品表面和界面的电子状态,发现C1s谱在高结合能端出现氧化特征的肩峰,表明真空蒸发沉积的LiBq4分子存在明显的氧化现象;对B1s谱的分析发现,界面处B原子的相对值远低于理论值,说明界面处存在B原子离解,导致了LiBq4分子的更高氧化态;从C1s谱发现,表面污染C的比例很高,而界面处大为下降,原因是表面吸附了气体,从而证实了LiBq4表面存在大量空隙和裂缝。定量研究发现,界面处存在N原子与In、Sn原子的相互作用,这将影响LiBq4的发光颜色。更多还原

【Abstract】 Blue OLED is very crucial to realize full-color displays. It was harder to gain highly efficiency blue OLEDs compared with red and green OLEDs. LiBq₄ was supposed to be a newly potential blue organic light-（emitting） material. As the states of the interface between organic layer and electrode and the film quality of （organic） layer affect the properties of OLEDs, we investigated the surface and interface states of LiBq₄/ITO by using atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. LiBq₄ was deposited on ITO coated glass by routine vacuum evaporation. The thickness of LiBq₄ was about 200 nm. The surface morphology of LiBq₄ was checked by AFM within a area of 8.0 μm×8.0 μm both in lateral and topographic force contact modes. XPS was introduced to study the surface and interface electronic states of LiBq₄/ITO. The scan spectrum was analyzed and the peaks of elements were deconvoluted to further investigate the chemical states of LiBq₄.AFM results show that the surface of LiBq₄ on ITO was very rough with many cracks and pores, indicating poor film quality of LiBq₄ on ITO. From the analysis of the XPS spectrum, we found that, the concentration of contaminated C atoms was very high in the surface of LiBq₄/ITO, which reduced significantly in the interface. This was another proof of the existence of cracks and pores in LiBq₄, that these cracks and pores can lead to heavy absorption of gas molecules; LiBq₄ was partially oxidized showed by the emergency of an oxidizing cha-（racterized） shoulder peak in the C1s spectrum; The relative concentration of B atoms reduced in the interface, which indicate that some B atoms detached from LiBq₄ and lead to the further oxidization of LiBq₄; from the spectrum of N1s, we found that unlike the case in Alq₃, no evidence shows B atoms bonding to N atoms through coordination, which leads to blue shift of the EL spectrum of LiBq₄. But in the interface, a new shoulder peak emerged which may be caused by N atoms bonding with In and Sn atoms came from ITO layer. It may affects the EL spectrum of LiBq₄ based OLEDs. From the B1s spectrum, we can also see that B atoms were in high valence, which agreement with LiBq₄ molecular structure.更多还原