Based On The Pt Organic Phosphorescent Devices And Woled

Organic Light-Emitting Diode (OLED) is a new generation of flat panel display technology having advantages of low driving voltage, all solid-state, light-emitting brightness, wide angle, fast response rate, etc. But the device mechanism of OLED is still not clear in some places. The life of device, aging problems and high manufacturing costs prevent its rapid development to a large extent. Aiming at those problems, some basic and systematic works have been performed to focus on performance of new phosphorescent material and fabrication process.1.A new type of red phosphorescent Pt-based materials TOPPPt has been researched including synthesis, UV-visible spectrum and lifetime. Using TOPPPt doped into polymer host material PVK in the emitting-layer with different doped concentration, the devices have been fabricated as following structure: ITO/PVK:TOPPPt (x wt%)/ BCP(10 nm)/Alq3(10 nm)/Mg:Ag, x=0.5,1,2,4. The fabrication of emitting-layer used method of spin-coating process which could simplify the process flow, and this is also an explore on the preparation of small molecule light-emitting materials device. Different doping concentration got different performance indicated that both energy transfer and charge trapping have a significant influence on the performance. With 4% doping concentration, the devices obtained maximum brightness of 2100 cd/m2 at the drive voltage of 24 V. Electroluminescence of devices did not change with the bias voltage and doping concentration varity, so the device had good stability.2.Through changing the thickness of BCP and Alq3 layer, the optimized device structure have been obtained. With BCP thickness 20nm and doped concentration 0.5%, device achieved the maximum current efficiency of 2.3 cd/A.The important factors for the improvement of device performance have been investigated by electron transport layer between the emitting-layer and the cathode. This method had some guidance for optimizing the OLED structure.3.Based on the fourth chapter, WOLED has been fabricated with two doping emitting layer. Blue dye EB53 is doped in Alq3, and red dye EY52 doped in NPB, through blue light and orange light colors mixing, white light has been achieved which determined by dye layers'thickness and doping concentration. With structure of ITO/ NPB(20 nm) / NPB:EY52(1.6%; 20 nm) /Alq3: EB53(3%;40 nm) / Alq3(20 nm) / Mg:Ag device has gotten the color coordinates of (0.31,0.35) within the white range. The max efficiency of this device was 8.78 cd/A while current density is 18 mA/cm2 .Under the 13.5 V voltage, device has obtained maximum brightness of 5650 cd/m2.4.White device'color coordinate had drift phenomenon at under different applied voltage. In order to optimize the color stability of white device, the device has been fabricated as follows structure: ITO / NPB (20 nm) / NPB: EY52 (1.6%; 20 nm) / Alq3: EB53(3%; 40 nm) / BCP(20 nm) / Alq3(20 nm) / Mg: Ag. A layer of BCP has been introduced as hole blocking layer to adjust the device within the carrier's balance and carrier recombination region. With voltage changed from 9 to 13 V, electroluminescence spectra almost unchanged, CIE color coordinates varied from (0.32,0.36) changed to (0.31,0.34) which changed small in the white area relatively. The structure of the device had good color stability.