微腔效应在有机电致发光二极管中的研究与应用

发布时间：2018-01-26 14:36

本文关键词： 有机电致发光器件微腔效应底发光顶发光出光耦合层　出处：《南京邮电大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文采用了金属分别做为半反射电极和全反射电极的双金属电极结构制备了高性能的有机微腔电致发光器件,电极都是由金属Al构成,具体工作包含以下几个方面:(1)在底发光OLED中,首先优化半透明阳极Al的厚度,使其光学和电学性能获得最佳协调性,半反射电极厚度为16nm时器件的性能最优,电流效率最大值为4.03cd/A。由于在半透明的金属电极出光侧加上耦合层会改善发光性能,基于此我们研究了耦合层材料的厚度和折射指数与器件性能之间的关系。本论文选用Alq3和BCP作为出光耦合层研究其对微腔性能的影响。实验中获得:50nm厚度的BCP作为出光耦合层时可使电极在530nm处的透光率从45%提高到56%,相应发光器件的电流效率也达到5.49cd/A,比ITO标准器件的效率(5.0cd/A)提高了10%。并且当观察角度从0o增加到60o时,EL谱谱峰移动的距离也从28nm减小到了12nm,大幅度减弱了微腔器件角度依赖的特性。(2)在顶发光OLED中,由于作为顶电极的薄金属Al极易在空气中氧化,因此器件在蒸镀完成之后需要在氮气环境中进行封装,本节采用传统的盖玻片封装方式对器件进行封装处理。另外,选用折射指数较高的有机材料BCP作为光输出耦合层蒸镀在器件阴极的上方,有效地改善了阴极的透光率,使器件的效率提高了12%,达到6.51cd/A。由于微腔效应强度的减弱,器件的角度依赖问题也得到了显著地改善。(3)研究了MoO3和V2O5作为空穴注入层时对双Al电极结构的倒置发光器件的修饰作用,器件结构为glass/Al/LiF/Alq3/NPB/MoO3 or V2O5/Al。结果表明V2O5可以更有效地提高阳极Al的空穴注入能力,器件的开启电压均有所下降:底发光倒置OLED的开启电压从4.0V降到3.0V,顶发光倒置OLED的开启电压从3.8V降低到3.2V;效率方面,也分别从3.70cd/A提高到3.85cd/A,6.05cd/A提高到6.18cd/A。
[Abstract]:In this thesis, high performance organic microcavity electroluminescent devices were fabricated by using metal as semi-reflective electrode and total reflection electrode, respectively. The electrodes were all composed of metal Al. The specific work includes the following aspects: 1) in the bottom luminescent OLED, the thickness of translucent anode Al is optimized to achieve the optimum coordination between optical and electrical properties. The maximum current efficiency of the device is 4.03 CD / A when the thickness of the semi-reflective electrode is 16 nm. Due to the addition of coupling layer to the output side of the translucent metal electrode, the luminescence performance can be improved. Based on this, we study the relationship between the thickness and refractive index of the coupling layer material and the performance of the device. In this thesis, we choose Alq3 and BCP as the optical coupling layer to study the effect of the coupling layer on the performance of the microcavity. 50 nm thick BCP can increase the transmittance of the electrode from 45% to 56% at 530 nm as the optical coupling layer. The current efficiency of the corresponding device is 5.49 cdr / A, which is 10% higher than that of the ITO standard device, and when the viewing angle is increased from 0 o to 60 o. The distance of El peak shift also decreased from 28 nm to 12 nm, which greatly weakened the angle-dependent characteristics of microcavity devices. As the thin metal Al as the top electrode is easily oxidized in air, the device needs to be encapsulated in nitrogen environment after evaporation. In this section, the traditional cover glass packaging method is used to package the device. In addition, BCP, an organic material with high refraction index, is used as the photo-output coupling layer to be evaporated over the cathode of the device. The transmittance of the cathode is improved effectively, and the efficiency of the device is improved by 12%, reaching 6.51 CD / A. The intensity of the microcavity effect is weakened. The effect of MoO3 and V _ 2O _ 5 as the hole implantation layer on the inverted light-emitting devices with double Al electrode structure is also studied. The device structure is glass/Al/LiF/Alq3/NPB/MoO3 or. The results of V _ 2O _ 5 / Al _ 2O _ 5 show that V _ 2O _ 5 can improve the hole implantation ability of anode Al more effectively. The switching voltage of the device is decreased: the starting voltage of the bottom luminous inverted OLED is decreased from 4.0V to 3.0V, and the top-luminous inverted OLED voltage decreases from 3.8V to 3.2V; Efficiency also increased from 3.70 cdr.A to 3.85cdpA6.05cdpA to 6.18cdpr.a.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN383.1

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