https://scholars.lib.ntu.edu.tw/handle/123456789/415915
Title: | Carrier Transport and Recombination Mechanism in Blue Phosphorescent Organic Light-Emitting Diode with Hosts Consisting of Cabazole- and Triazole-Moiety | Authors: | Cheng, T.-Y. JIUN-HAW LEE Chen, C.-H. Chen, P.-H. Wang, P.-S. Lin, C.-E. Lin, B.-Y. Lan, Y.-H. Hsieh, Y.-H. Huang, J.-J. Lu, H.-F. Chao, I. MAN-KIT LEUNG Chiu, T.-L. Lin C.-F. |
Issue Date: | 2019 | Journal Volume: | 9 | Journal Issue: | 1 | Source: | Scientific Reports | Abstract: | In this study, we demonstrated a blue phosphorescent organic light-emitting diode (BPOLED) based on a host with two carbazole and one trizole (2CbzTAZ) moiety, 9,9′-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)-1,3-phenylene)bis(9H-carbazole), that exhibits bipolar transport characteristics. Compared with the devices with a carbazole host (N,N’-dicarbazolyl-3,5-benzene, (mCP)), triazole host (3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, (TAZ)), or a physical mixture of mCP:TAZ, which exhibit hole, electron, and bipolar transport characteristics, respectively, the BPOLED with the bipolar 2CbzTAZ host exhibited the lowest driving voltage (6.55 V at 10 mA/cm 2 ), the highest efficiencies (maximum current efficiency of 52.25 cd/A and external quantum efficiency of 23.89%), and the lowest efficiency roll-off, when doped with bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) as blue phosphor. From analyses of light leakage of the emission spectra of electroluminescence, transient electroluminescence, and partially doped OLEDs, it was found that the recombination zone was well confined inside the emitting layer and the recombination rate was most efficient in a 2CbzTAZ-based OLED. For the other cases using mCP, TAZ, and mCP:TAZ as hosts, electrons and holes transported with different routes that resulted in carrier accumulation on different organic molecules and lowered the recombination rate. © 2019, The Author(s). |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062613276&doi=10.1038%2fs41598-019-40068-w&partnerID=40&md5=04b62d5f65ff318ebc63742b5edd8996 https://scholars.lib.ntu.edu.tw/handle/123456789/415915 |
ISSN: | 20452322 | DOI: | 10.1038/s41598-019-40068-w |
Appears in Collections: | 化學系 |
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