Toward high efficiency green phosphorescent organic light-emitting diodes by fine tuning the charge transporting properties of 1,2,4-thiadiazole based hosts
| Autor: | Lei Wang, Wenzhi Zhang, Jiangjiang Jin, Shaoqing Zhuang, Biao Pan, Zhi Huang |
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| Rok vydání: | 2015 |
| Předmět: |
Benzimidazole
Materials science Maximum power principle Carbazole business.industry Charge (physics) General Chemistry Condensed Matter Physics Electronic Optical and Magnetic Materials Biomaterials chemistry.chemical_compound chemistry Materials Chemistry OLED Optoelectronics Quantum efficiency Electrical and Electronic Engineering Phosphorescence business Voltage |
| Zdroj: | Organic Electronics. 16:177-185 |
| ISSN: | 1566-1199 |
| DOI: | 10.1016/j.orgel.2014.11.004 |
| Popis: | Two novel host materials, from bipolar-type BzCzTHZ (5-(2-(9H-carbazol-9-yl)phenyl)-3-(3-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,2,4-thiadiazole) to electron-type DBzTHZ (3,5-bis(3-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,2,4-thiadiazole), were designed and synthesized utilizing the unsymmetric intermediate of 3-bromo-5-chloro-1,2,4-thiadiazole as the center. Their thermal, photoelectronic, energy levels, charge transport mobility properties can be easily tuned by changing the radio of benzimidazole/carbazole moieties. Using a common device structure ITO/MoO3 (10 nm)/TAPC (50 nm)/TCTA (5 nm)/host: Ir(ppy)3 (3 wt%) (20 nm)/TmPyPB (45 nm)/LiF (1 nm)/Al (100 nm), highly efficient green electrophosphorescent devices were successfully achieved. Devices hosted by DBzTHZ and BzCzTHZ achieved maximum power efficiencies (ηp, max) of 95.2 and 86.2 lm/W, corresponding to maximum quantum efficiency (ηEQE, max) of 23.4 and 22.2%, respectively. Moreover, the electron-type host DBzTHZ based device exhibits an ideal turn-on voltage (2.5 V at 1.0 cd/m2). These results demonstrate that electron-type hosts are competitive with bipolar hosts. |
| Databáze: | OpenAIRE |
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