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Balancing Charge Injection and Transport in Organic Light-emitting Diodes with a Transparent Conductive Tungsten Oxide Layer

Published online by Cambridge University Press:  20 February 2014

R. Acharya ,
X. M. Li ,
Y. Lu  and
X. A. Cao
R. Acharya
Affiliation:
Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA
X. M. Li
Affiliation:
Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA
Y. Lu
Affiliation:
Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA
X. A. Cao
Affiliation:
Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA
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Abstract

High-brightness green phosphorescent hybrid inorganic-organic light-emitting diodes (HyLEDs) and inverted HyLEDs (IHyLEDs) have been demonstrated. The devices comprised a transparent and conductive WO3 layer deposited by thermal evaporation, which improved both hole injection and transport, and led to more balanced charge injection and significant performance enhancement. At 20 mA/cm2, the HyLEDs had a low operation voltage of 6.1 V, 0.8 V lower than that of OLEDs with an organic hole transport layer. With an optimized layer structure, the HyLEDs reached 104 cd/m2 brightness at 7.3 V. At this brightness level, the current efficiency was 55.2 cd/A, 57% higher than that of the OLEDs. In the IHyLEDs, facile hole injection and transport through WO3 was balanced by electron injection from the indium-tin-oxide (ITO) cathode overcoated with nanometer-thick Ca, leading to a low turn-on voltage of ∼6 V. Brightness of 8133 cd/m2 was reached at 20 mA/cm2 and the corresponding current efficiency was 40 cd/A. The hybrid devices also exhibited markedly improved stability under constant-current stressing due to the robust WO3 hole transport layer.

Keywords

optoelectronicorganicelectronic material
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1629: Symposium N - Functional Aspects of Luminescent and Photoactive Organic and Soft Materials , 2014 , mrsf13-1629-n08-26
Copyright
Copyright © Materials Research Society 2014 

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References

REFERENCES

Nuesch, F., Carrara, M, Schaer, M, Romero, D., Zuppiroli, L, Chem. Phys. Lett. 347, 311 (2001).CrossRefGoogle Scholar
Ding, X. M., Hung, L. M., Cheng, L. F., Deng, Z. B., Hou, X. Y., Lee, C. S., and Lee, S. T., Appl. Phys. Lett. 76, 2704 (2000).CrossRefGoogle Scholar
Li, J., Yahiro, M., Ishida, K., Yamada, H., and Matsushige, K., Synth. Met. 151, 141 (2005).CrossRefGoogle Scholar
Meyer, J., Hamwi, S., Bülow, T., Johannes, H.H., Riedl, T., and Kowalsky, W., Appl. Phys. Lett. 91, 113506 (2007)CrossRefGoogle Scholar
Cao, X. A. and Zhang, Y. Q., Appl. Phys. Lett. 100, 183304 (2012).CrossRefGoogle Scholar
Zhang, Y. Q., Acharya, R., and Cao, X. A., J. Appl. Phys. 112, 013103 (2012).CrossRefGoogle Scholar
Chu, T. Y., Chen, J. F., Chen, S. Y., Chen, C., Chen, C. H., Appl. Phys. Lett. 89, 053503 (2006).CrossRefGoogle Scholar
Lee, Y., Kim, J., Kwon, S., Min, C., Yi, Y., Koo, B., Hong, M., Org. Electron. 9, 407 (2008).CrossRefGoogle Scholar
Bolink, H. J., Coronado, E., Repetto, D., Sessolo, M., Barea, E. M., Bisquert, J., Garcia-Belmonte, G., Prochazka, J., and Kavan, L., Adv. Funct. Mater. 18, 145 (2008).CrossRefGoogle Scholar
Lee, H., Park, I., Kwak, J., Yoon, D. Y., and Lee, C., Appl. Phys. Lett. 96, 153306 (2010).CrossRefGoogle Scholar
Wood, V., Panzer, M., Halpert, J., Caruge, J., Bawendi, M., Bulovic, V., ACS Nano 3, 3581 (2009).CrossRefGoogle Scholar
Han, S., Shin, W., Seo, M., Gupta, D., Moon, S., Yoo, S., Appl. Phys. Lett. 96, 193501 (2010).Google Scholar
Shaheen, S. E., Jabbour, G. E., Morrell, M. M., Kawabe, Y., Kippelen, B., Peyghambarian, N., Nabor, M. F., Schlaf, R., Mash, E. A., Armstrong, N. R., J. Appl. Phys., 84, 2324 (1998).CrossRefGoogle Scholar