Researching On The Functional Layer And The Mutually Doped Transitional Layer Of OLED

Organic/polymeric electroluminescence is a newly-emerging display technique. From the aspects of display area, contrast color fidelity, response time, visual angle and brightness, the organic electroluminesent display device has the advantages over other display techniques. It is expected to replace liquid crystal display in the future. How to further improve the luminous efficiency, brightness, life length and operating voltage of organic light-emitting diodes (OLEDs) is still in research. To achieve these goals, we should pay attention to the significance of the design of the device structure as well as materials. In this paper, we introduce a mutually doped transitional layer to modify the interface structure used commonly, expecting to increase the performance of OLED. This paper has five chapters:The first chapter: describing the evolution of the Organic/polymeric electroluminescent device, analyzing its advantages and disadvantages when acting as flat display, introducing the OLED structure, luminous mechanics and the methods of increasing the luminous efficiency, etc.The second chapter: discussing the effects on the performance of OLED if the LiF acts as an electron inject layer and/or CuPc acts as a hole inject layer.The third chapter: studying three mutually doped transitional layer structures' effects on the performance of OLED. The three structures are the thin mutually doped transitional layer with concentration gradually changing structure, the thicker transitional layer with uniform concentration structure and the transitional layer doped with fluorescent dye structure.The fourth chapter: introducing the display techniques in the future and pointing out that the OLED has a brilliant prospect.The fifth chapter: summing up the conclusions of this paper.The influence of functional layer upon the performance of the OLED is studied ahead the mutually doped transitional layer. LiF acting as the electron inject layer can increase the luminous efficiency and decrease the operating voltage; CuPc acting as the hole inject layer can improve the device's stability, but at the same time, it will cause the reduction of brightness and efficiency. In the study of the mutually dopedtransitional structure, we discover that the interfaces of organic have great effects on the device's performance. When a mutually doped transitional layer is introduced, no matter it is added to the interspace of electron transport layer and hole transport layer or to the interspace of the hole transport layer and hole inject layer, it can reduce the defects of the interface and result in the increase of brightness and the decrease of the operating voltage obviously. We also discover that luminous efficiency is increased markedly and two zones emission phenomenon appears if a fluorescent dye is added to the transitional layer between the ETL and HTL. This paper supports the standpoint that the interfaces of organic layers should be removed to make charge carriers move smoothly in order to improve the performance of OLED. At the end of the paper, other new present display techniques are compared with OLED, pointing out that the OLED is the most promising display technique to replace liquid crystal display in the future and has a brilliant future.