溶液加工有机电致发光器件阴极界面层的应用与研究

发布时间：2018-01-15 03:26

本文关键词：溶液加工有机电致发光器件阴极界面层的应用与研究　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：有机发光二极管(OLEDs)因其独特的优势,在大面积平板显示器和固态照明上展现出巨大潜力,受到了各类研发单位和企业的重视。OLEDs制备工艺主要有蒸镀技术和溶液加工技术。相比于蒸镀技术,溶液加工制备OLEDs技术具备低成本易于大面积生产的优势,目前,溶液加工制备OLEDs仍然存在一些技术难题,如器件的效率,寿命,稳定性等。如何在现有的材料基础之上,对器件性能进行大幅度改善,这就主要取决于器件的结构和物理机制的研究。有机电致发光器件(OLEDs)是双注入型器件,器件效率主要依赖于电子和空穴载流子从两端平衡有效的注入,器件界面工程的研究是帮助电子和空穴有效注入一种可行的方法。由于大多数有机发光材料具有较低LUMO能级,发光层和金属阴极存在较大注入势垒,要想获得高效稳定的器件,这就需要降低电子的注入势垒。通常,通过在阴极引进阴极界面层,以降低电极和有机发光层界面之间的势垒,帮助电子有效注入。本文中采用了商业化的聚合发光材料P-PPV和简单的器件结构,以阴极界面层作为研究对象,基于溶液加工的方式来研究发光器件的阴极界面层,以获得高效稳定的发光器件。立足于高效率稳定的印刷型的聚合物电致发光器件,我们把新颖的交联基团的、醇溶性的、胺基功能化共轭聚合物(PF3N-OX)和少量环氧树脂(Epoxy)共混形成功能缓冲层,引入到阴极喷墨的聚合物发光二极管中,制备出了低启亮电压、高效率的印刷型的器件。缓冲层位于印刷阴极和发光层之间,它能够阻止溶剂侵蚀,保证电子有效注入。阴极印刷Ag电极器件的启亮电压降低到3.25 V,最大电流效率(LEmax)达到8.77 cd/A,相比于蒸镀型Ag电极器件,喷墨打印Ag电极器件的启亮电压降低了2.25 V,器件的最大亮度提高了70%。值得注意,采取喷墨打印制备的导电纳米颗粒阴极能保证高分辨率的阴极图案,以及精细阴极的良好导通,且加工过程中不会对有机层产生机械压力。我们用含有氧化乙烯官能团的醚溶剂修饰阴极界面制备高效稳定铝阴极聚合物电致发光器件。实验中,我们通过旋涂适量的醚溶剂到聚合物发光层薄膜表面,随后,蒸镀金属铝(Al)电极。器件光电性能测试结果表明,醚溶剂处理后,Al阴极器件最大电流效率是19.54 cdA-1,此时电压5.25 V,相比没有醚溶剂处理的器件,效率有三十几倍的提高。效率的提高是由于有机功能层和Al电极的阴极界面层电子注入势垒降低,光生伏打测试和X射线光电子能谱仪的结果证明,真空蒸镀的Al可以氧化残留的醚溶剂,产生了碳化物,这种碳化物有利于电子注入势垒降低,帮助了电子注入。
[Abstract]:Organic light emitting diodes (OLEDs) show great potential in large-area flat-panel displays and solid-state lighting due to their unique advantages. All kinds of R & D units and enterprises pay attention to. OLEDs preparation technology mainly includes evaporation technology and solution processing technology, compared with evaporation technology. Solution processing (OLEDs) technology has the advantages of low cost and easy to be produced in large area. At present, there are still some technical problems in the preparation of OLEDs by solution processing, such as the efficiency and lifetime of devices. How to improve the performance of the device based on the existing materials. This mainly depends on the research of the structure and physical mechanism of the device. The organic electroluminescent device (OLEDs) is a dual-injection device. The device efficiency mainly depends on the effective injection of electron and hole carriers from both ends. The study of device interface engineering is a feasible method to help the effective injection of electrons and holes. Because most organic luminescent materials have lower LUMO energy level, there are large injection barriers in the luminescent layer and metal cathode. In order to obtain efficient and stable devices, it is necessary to reduce the electron injection barrier. Generally, the cathode interface layer is introduced at the cathode to reduce the barrier between the electrode and the organic luminescent layer interface. In this paper, a commercial polymeric luminescent material P-PPV and a simple device structure are used, and the cathode interface layer is used as the research object. Based on the solution processing method, the cathode interface layer of the luminescent device is studied to obtain the high efficiency and stable luminescent device, which is based on the high efficiency and stable printing polymer electroluminescent device. A novel cross-linked group, alcohol-soluble, amine-functionalized conjugated polymer (PF3N-OX) was blended with a small amount of epoxy resin to form a functional buffer layer. A low starting voltage and high efficiency printed device was fabricated by introducing it into the polymer light-emitting diode with cathode inkjet. The buffer layer is located between the printed cathode and the luminescent layer, which can prevent solvent erosion. To ensure effective electron injection, the starting voltage of cathode printed Ag electrode device is reduced to 3.25 V, and the maximum current efficiency is 8.77 cd/A. Compared with the evaporated Ag electrode device, the starting voltage of the ink-jet printing Ag electrode device is reduced by 2.25 V, and the maximum brightness of the device is increased by 70 parts. The conductive nano-particle cathode prepared by inkjet printing can guarantee high resolution cathode pattern and good conduction of fine cathode. In addition, there is no mechanical pressure on the organic layer in the process of processing. High efficient and stable aluminum cathode polymer electroluminescent devices are prepared by modifying the cathode interface with ether solvent containing ethylene oxide functional group. We spin-coated a proper amount of ether solvent onto the surface of the polymer luminescent film and then evaporated the Al-Al electrode. The photoelectric properties of the device showed that the solvent was treated with ether. The maximum current efficiency of Al cathode device is 19.54 cdA-1, and the voltage is 5.25 V, compared with the device without ether solvent treatment. The efficiency is improved by more than 30 times. The efficiency is due to the decrease of electron injection barrier between the organic functional layer and the cathode interface layer of Al electrode. The results of photovolt test and X-ray photoelectron spectrometer show that the increase is due to the decrease of the electron injection barrier in the cathode interface layer of the organic functional layer and the Al electrode. The vacuum evaporated Al can oxidize the residual ether solvent and produce carbides. This kind of carbides is conducive to the reduction of the electron injection barrier and helps the electron injection.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN383.1

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