Efficient Doped Red Organic Electroluminescent Devices with a New Host System

• Main Authors: TSWEN-HSIN LIU, 劉醇炘
• Other Authors: Chin Hsin Chen
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/84292797465155065387

碩士 === 國立交通大學 === 應用化學系 === 91 === In this thesis, we have studied the device optimization of red 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyl-julolidyl-9-enyl)-4H-pyran（DCJTB）dye doped Alq3 emitters in OLED. By varying the hole injection materials and thickness of hole-transport layer, efficiency of 2.52 cd/A and near saturated CIE color coordinates of x = 0.641, y = 0.356 was achieved without needing additional doping of emitting assist dopant (rubrene). From experiments with film thickness variation, it is concluded that the improved EL performance and color saturation are due to the synergistic effects of microcavity, device structural optimization as well as optimal doping of DCJTB. Furthermore, we have also developed what appears to be one of the highest luminance efficiency ever reported for the archetypical DCJTB doped red emitter at 4.44 cd/A at 20 mA/cm2 and 6.77 V with a near saturated CIEx,y red color coordinate of [0.65, 0.35]. By doping DCJTB into the novel co-host matrix emitting system of rubrene/Alq3, we have also successfully eliminated the problem of luminescence quenching at high drive voltage and achieved a “flat” cd/A vs J response that is highly desirable for passive as well as active matrix full color OLED flat panel display applications.