摘要
使用真空热蒸发镀膜法,在OLED层状结构中引入不同厚度的LiF作阳极修饰层,制备了结构为ITO/LiF/TPD/Alq3/Al的器件。LiF超薄层的引入较好地修饰了ITO表面,减少了阳极和有机层界面缺陷态的形成,增强了器件的稳定性。实验结果表明:LiF层有效地阻挡空穴注入,增强载流子注入平衡,提高了器件的亮度和效率,含有1nm厚LiF空穴缓冲层器件的性能最好,效率较不含缓冲层器件提高了近1.5倍。
Tremendous progress has been made in the science and technology of organic light-emitting diode in developing flat panel displays. OLED efficiency and lifetime are the primary issues limiting the widespread commercial use. To solve the problem, finding out novel materials and applying new structure are usual methods. The degradation of the interfaces between electrode and organic layer is also an important factor for the stability. Up to now, different treatment both physical and chemical technique has been used to modify the interface, and also, there is a good choice of inserting a nano-layer into the interface.
Organic light-emitting diodes inserted LiF film, which usually is used for cathode modifying layer, between anode and organic layer were fabricated by vapor thermal deposition. The structure of the diode is ITO / LiF/TPD（30 nm）/Alq3 （40 nm）/Al（ 100 nm） （TPD： N, N′-diphenyl-N, N′-bis（3-methylphenyl ）-1,1′ -biphenyl-4, 4′-diamine, Alq3 ： tris （ 8-quinolinolato）- aluminum）, and the thicknesses of the LiF film are 0.5,1.0,1.5 and 2.0 nm detected by INFCON XTM/2 deposition monitor. The insertion of the ultra-thin LiF layer between ITO and organic layer improves the photoelectric characteristics of the diodes directly, which blocks the hole injection and improves the efficiency of the diodes. Firstly, the ITO surface is smoothed after depositing a LiF film and that may reduces the formation of non-emissive traps and block the diffusion of In ^＋ ion from ITO to organic layer. The efficient recombination of holes and electrons in emissive layer improves the luminance and efficiency. Secondly, the LiF buffer layer can blocks hole injection and improves the properties of the diodes, however, a thicker LiF layer can reduce the characteristic of the diodes and it was necessary to optimize the LiF thickness. Finally, it was found that the luminance and efficiency of the diode are maximized when 1.0 nm LiF hole buffer layer is inserted between ITO and TPD.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2009年第1期55-58,共4页
Chinese Journal of Luminescence
基金
广东省自然科学基金资助项目(06025173)
