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基于共轭聚合物光电器件的性能与聚合物的表面形貌、分子取向、以及与金属电极形成的界面结构密切相关.本文利用原子力显微镜(AFM)、同步辐射光电子能谱(SRPES)和近边X射线吸收精细结构谱(NEXAFS)等,研究了聚(9,9-二辛基芴并苯噻二唑)(F8BT)薄膜的表面形貌、分子取向及其与Al电极形成界面过程的结构变化.结果表明,在略低于F8BT玻璃转变温度(Tg=130℃)条件下对F8BT薄膜进行退火,可明显增加薄膜的表面粗糙度,薄膜中F8BT的分子取向角约为49,9,9-二辛基芴单元(F8)与苯噻唑单元(BT)几乎在同一平面.在Al/F8BT界面形成过程中,Al与F8BT中的C,N和S均发生不同程度的化学反应,并导致价带结构和未占据分子轨道(LUMO)态密度的变化.Al对F8BT进行n型掺杂引起F8BT能带弯曲的同时,未占据能级被部分占据,更多的电子将被注入到LUMO+1中.通过考察价带电子结构、芯能级位移及二次截止边的变化,绘制了清晰的Al/F8BT界面能级图.
The properties of conjugated polymer based optoelectronic devices are closely related to the surface morphology, molecular orientation, and interface structure of the polymer electrodes.In this paper, atomic force microscopy (AFM), synchrotron radiation photoelectron spectroscopy (SRPES) X-ray absorption fine structure spectrum (NEXAFS) and so on. The surface morphology, molecular orientation and the structure of the interfacial process with polycrystalline (9,8-dioctylfluorenobenzothiazole) (F8BT) The results show that annealing the F8BT thin film at a temperature slightly lower than the F8BT glass transition temperature (Tg = 130 ℃) can obviously increase the surface roughness of the film, and the molecular orientation angle of F8BT in the film is about 49,9,9 - dioctylfluorene unit (F8) is nearly in the same plane as that of the benzothiazole unit (BT) .Cu, N and S in Al and F8BT chemically react to some extent during Al / F8BT interface formation, Valence band structure and unoccupied molecular orbital (LUMO) state density.Al-doped F8BT n-type doping caused F8BT band bending while the unoccupied level is partially occupied, more electrons will be injected into the LUMO + 1 by examining the valence band electronic structure, the core level displacement and the second cut-off edge Change, drawing a clear Al / F8BT interface states FIG.