Hostname: page-component-848d4c4894-v5vhk Total loading time: 0 Render date: 2024-06-30T18:55:19.197Z Has data issue: false hasContentIssue false

Current Density Dependence of Transient Electroluminescence in Phosphorescent Organic Light-Emitting Diodes

Published online by Cambridge University Press:  14 January 2011

Hirotake Kajii
Affiliation:
Center for Advanced Science and Innovation, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Noriyoshi Takahota
Affiliation:
Center for Advanced Science and Innovation, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Yadong Wang
Affiliation:
Center for Advanced Science and Innovation, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Yutaka Ohmori
Affiliation:
Center for Advanced Science and Innovation, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Get access

Abstract

The transient electroluminescence (EL) of phosphorescent organic light-emitting diodes (OLEDs) was investigated. The behaviors of the transient characteristics are analyzed using the triplet-triplet annihilation model. The device exhibited a gradual decrease in quantum current efficiency owing to the triplet-triplet annihilation at a high current density. At a higher current density, the reduced rise and decay times are due to high-density triplet excitons related to the enhanced triplet-triplet annihilation and the increase of the nonradiative process. The modulation speed of the devices is mainly limited by the phosphorescent recombination lifetime.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Reineke, S., Lindner, F., Schwartz, G., Seidler, N., Walzer, K., Lüssem, B. and Leo, K., Nature 459, 234 (2009).Google Scholar
2. Kajii, H., Takahota, N., Sekimoto, Y. and Ohmori, Y., Jpn. J. Appl. Phys. 48, 04C176 (2009).Google Scholar
3. Baldo, M. A., Lamansky, S., Burrows, P. E., Thompson, M. E. and Forrest, S. R., Appl. Phys. Lett. 75, 4 (1999).Google Scholar
4. Hosokawa, C., Tokailin, H., Higashi, H. and Kusumoto, T., Appl. Phys. Lett. 60, 1220 (1992).Google Scholar
5. Kajii, H., Tsukagawa, T., Taneda, T., Yoshino, K., Ozaki, M., Fujii, A., Hikita, M., Tomaru, S., Imamura, S., Takenaka, H., Kobayashi, J., Yamamoto, F. and Ohmori, Y., Jpn. J. Appl. Phys. 41, 2746 (2002).Google Scholar
6. Ohmori, Y., Kajii, H., Kaneko, M., Yoshino, K., Ozaki, M., Fujii, A., Hikita, M., Takenaka, H. and Taneda, T., IEEE J. Sel. Top. Quantum Electron. 10, 70 (2004).Google Scholar
7. Borek, C., Hanson, K., Djurovich, P. I., Thompson, M. E., Aznavour, K., Bau, R., Sun, Y., Forrest, S. R., Brooks, J., Michalski, L. and Brown, J. J., Angew. Chem., Int. Ed. 46, 1109 (2007).Google Scholar
8. Baldo, M. A., Adachi, C. and Forrest, S. R., Phys. Rev. B 62, 10967 (2000).Google Scholar