Design And Fabrication Of Organic Light-Emitting Devices

The basic organic light-emitting device(OLED) consists of a number of ultra-thin organic layers between two electrode. Under low applied voltage, the recombination of carriers coming from cathode and anode can produce intense light output. Since 1987, OLEDs have received much attention and now are beginning to enter the display markets where they may eventually be the dominant flat panel display devices.This thesis mainly discusses the OLED device design, fabrication and characterization.The second chapter is a review of the concepts and theories describing the mechanisms of organic electroluminescence. Making use of these concepts, chapter 4 discusses the main characteristics of the OLED with ITO/TPD/Alqs/LiF/Al structure.Chapter 3 provides the in-line processing system for fabricating OLED. A simple matrix display panel is made and measured using hand-made luminous characteristics test system. Negative differential resistance, luminance uniformity, electrical and the optical crosstalk are observed and studied independently with device models to describe the experimental results. The models results are presented which show that pinholes in layers, electrode resistivity, reverse current of OLED, waveguided light are the key issues for the design of OLED display device. The models also give quantitative description to minimize the impact of these effects on display characteristics.Based on above principles and techniques, we demonstrate both organic light-emitting diodes and seven segment OLED display having adequate performance for display applications.The storage and operation stability of OLED are measured using hand-made lifetime test system. Two sealing technique which use gastight casing and multi-layer to achieve H2O, Oa barriers are presented, and successfully improve the2stability of the OLED.In many applications, it is advantageous to employ an OLED display having topside light output. An Ag/MgFa multi-layer structure cathode is presented and the semitransparent OLED has been demonstrated in chapter 6.Finally, the conclusion of this thesis and the prospects for OLED displays are considered. Only after critical issues such as device efficiency, sealing and the manufacturability of matrix display panel are dissolved, will OLED technology prove itself profitable in display market.