| Autor: |
Jou, Jwo-Huei, Chen, Cheng-Hua, Tseng, Jing-Ru, Peng, Shiang-Hau, Chen, Po-Wei, Chiang, Cheng-I., Jou, Yung-Cheng, Hong, James H., Wang, Ching-Chiun, Chen, Chien-Chih, Tung, Fu-Ching, Chen, Szu-Hao, Wang, Yi-Shan, Chin, Chih-Lung |
| Zdroj: |
Journal of Materials Chemistry C; 2012, Vol. 1 Issue: 3 p394-400, 7p |
| Abstrakt: |
We discovered in this study the feasibility of using regular light-emitting dyes as an effective co-host, rather than a sensitizer, to markedly improve the efficiency of phosphorescent organic light emitting diodes. At 10 000 cd m−2, for example, the efficacy of a yellow emitter containing device was increased from 11.7 lm W−1to 15.4 lm W−1, an increment of 32%, as a sky-blue phosphorescent dye, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(iii) (FIrpic), was blended into a host of 4,4′,4′′-tri(N-carbazolyl)triphenylamine (TCTA). The efficacy at 1000 cd m−2was 26.7 lm W−1, the highest among all reported yellow OLEDs with a solution-processed emissive layer. The marked efficiency improvement may be attributed to the co-host having an electron trapping character, enabling excitons to generate on itself instead of on the guest, creating an additional efficiency-effective energy transfer route, and having a very efficient co-host to guest energy transfer. The most effective co-host may vary with the variation of the host employed, depending on the energy level pairing of the co-host and host. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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