High efficiency phosphorescent organic light-emitting diode by incorporating an electron transport material into emitting layer

• Main Authors: Bo-Syen Hsieh, 謝博旬
• Other Authors: Fuh-Shyang Juang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/x9tmtt

碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 98 === In this study, the hole transport-type host material (TCTA) was incorporated with the electron transport material (TmPyPB) as a mixed-host structure to future improving the injection of charge carriers and reduce the driving voltage of the phosphorescent organic light-emitting diodes (PHOLEDs). The charge carrier balance of PHOLED was achieved by using CsF as electron injection layer and optimizing the doping ratio of TCTA and TmPyPB (1:1). At a luminance of 1000 cd/m2, highly efficiency blue PHOLED shown the best yield of 34.7 cd/A and power efficiency of 24.8 lm/W. Furthermore, a highly efficiency two-components system white PHOLED can be obtained by doping Os(bpftz)2(PPh2Me)2 into the emitting layer of optimizing blue PHOLED. The driving voltage of 4.6V, yield of 37.4 cd/A, and power efficiency of 25.5 lm/W at a luminance of 1000 cd/m2 can be obtained. Finally, a high efficiency three-components system white PHOLED was fabricated by co-doping three phosphor dopant (Os(bpftz)2(PPh2Me)2, Ir(ppy)3 and FIrpic) into mixed-host (TCTA:TmPyPB) structure and optimizing the doping region and each layer thickness. From the experimental results, the optimal white PHOLED showed the driving voltage of 4.4 V, yield of 34 cd/A, and power efficiency of 24.2 lm/W at a luminance of 1000 cd/m2 can be observed. Furthermore, the efficiencies can be increased to 43.8 cd/A and 32 lm/W by attaching an outcoupling brightness enhancement film (BEF) onto glass substrate and the CIE coordinate exhibited blue-shift from (0.346, 0.374) to (0.316, 0.364) under different driving voltages.