摘要
主要报道在器件结构为玻璃衬底/Ag(阳极)/NPB(空穴传输层)/Alq3(电子传输及发光层)/Sm(半透明阴极)/Alq3的顶发射有机电致发光器件中,利用氧等离子体对阳极银的表面进行处理来降低阳极和空穴传输层(Ag/NPB)界面处的空穴注入势垒,提高顶发射有机电致发光器件的性能。主要研究了氧等离子体处理时间对阳极银和顶发射有机电致发光器件光电特性的影响。紫外光电子能谱表明,氧等离子体处理能有效降低Ag/NPB界面处的空穴注入势垒。通过优化处理时间获得最佳器件性能,优化后的器件最大效率可达6.14cd/A。
Organic light-emitting diodes （OLEDs） with a top-emitting configuration have been widely studied since they can realize high-performance active matrix flat panel display with integration of thin-film transistors within the substrates. Top-emitting OLEDs are generally composed of a reflective bottom anode, organic layers, and a semi-transparent top cathode for light out-coupling. The modification of the bottom anodes is essential for achieving high light-emitting efficiency. Here, efficient top-emitting OLEDs are fabricated with a structure of A1/Ag with O2-plasma modification/NPB （35 nm）/Alq3 （40 nm）/Sm （25 nm）/Alq3 （50 nm）, where N, N′-di （ naphthalene-1 -yl） -N, N′-diphenyl-benzidine （ NPB ） and tris （8-hydroxyquinolinato） alumi- num （Alq3） are used as a hole-transport layer and an electron-transport/emissive layer, respectively. The metals of silver （Ag） and samarium （Sm） are used as the reflective anode and the semitransparent cathode,respectively. A layer of Alq3 overlaid on Sm aims at enhancing light out-coupling efficiency and preventing Sm from oxidation rapidly. The Ag anode is subjected to 02 plasma treatment before depositing organic layers. The ultraviolet photoelectron spectroscopy （UPS） analysis shows that the hole injection barrier at Ag/NPB interface is effectively reduced from 1.43 to 1.10 eV by O2-plasma treatment. The influence of the 02 plasma treatment time on the device performance is also studied. The device performance of the top-emitting OLEDs is remar- kably enhanced by using Ag anode with O2-plasma modification. A maximum current efficiency of 6.14 cd/A is achieved at an optimal treating time of 60 s.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第6期859-863,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金面上基金(50573076)
吉林大学集成光电子实验室开放课题(2006-JLU-01)资助项目
关键词
有机电致发光
顶发射
注入势垒
氧等离子体
organic electroluminescence
top-emitting
injection barrier
02 plasma
