Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-25T21:04:08.128Z Has data issue: false hasContentIssue false

The Effects of Processing Conditions on the Efficiency and Lifetime of Organic Light Emitting Devices Incorporating a New Oxadiazole Derivative

Published online by Cambridge University Press:  15 March 2011

G.Y. Jung
Affiliation:
School of Engineering and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
C. Wang
Affiliation:
Department of Chemistry and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
P. Cea
Affiliation:
School of Engineering and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
C. Pearson
Affiliation:
School of Engineering and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
M.R. Bryce
Affiliation:
Department of Chemistry and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
M.C. Petty
Affiliation:
School of Engineering and Centre for Molecular and Nanoscale Electronics, University of Durham, South Road, Durham, DH1 3LE, UK
Get access

Abstract

The effects of processing conditions on the properties of organic light emitting devices (LEDs) based on rubrene-doped poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and a new electron transporting material, 2,5-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]pyridine, are reported. These dual-layer LEDs exhibited a higher quantum efficiency than observed for structures incorporating the more widely used electron transport compound 1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene (OXD-7). However, the as-prepared devices degraded relatively rapidly on storage (10-1 mbar, no applied bias). Thermal annealing of the degraded devices at 160 °C for 30 minutes restored the currents and light outputs close to those measured for fresh devices. The annealed LEDs exhibited a significant increase in their operating lifetime. Lifetime improvements could also be achieved by increasing the deposition rate and thickness of the thermally evaporated aluminium top electrode. These effects are attributed to better adhesion between the aluminium top electrode and the underlying electron transport layer.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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. Burroughes, J.H., Bradley, D.D.C., Brown, A.R., Marks, R.N., Mackay, K., Friend, R.H., Burn, P.L. and Holmes, A.B., Nature 347, 539 (1990).Google Scholar
2. Baldo, M.A., Lamansky, S., Burrows, P.E., Thompson, M.E. and Forrest, S.R., Appl. Phys. Lett. 75, 4 (1999).Google Scholar
3. Adachi, C., Tsutsui, T. and Saito, S., Appl. Phys. Lett. 55, 1489 (1989).Google Scholar
4. Strukelj, M., Papadimitrakopoulos, F., Miller, T.M., Rothberg, L.J. and Chandross, E.A., Science 267, 1969 (1995).Google Scholar
5. Weaver, M.S., O'Brien, D., Bleyer, A., Lidzey, D.G. and Bradley, D.D.C., in Proceedings of the 8th International Workshop on Organic and Inorganic Electroluminescence, Berlin, 1996, 207.Google Scholar
6. Hamada, Y., Adachi, C., Tsutsui, T. and Saito, S., Jpn. J. Appl. Phys. 31, 1812 (1992).Google Scholar
7. Dailey, S., Halim, M., Rebourt, E., Horsburgh, L.E., Samuel, I.D.W. and Monkman, A.P., J. Phys: Condens. Matter 10, 5171 (1998). C. Wang, M. Kilitziraki, J. A. H. MacBride, M. R. Bryce, L. Horsburgh, A. Sheridan, A. P. Monkman and I. D. W. Samuel, Adv. Mater. 12, 217 (2000).Google Scholar
8. Wang, C., Jung, G.Y., Hua, Y., Pearson, C., Bryce, M.R., Petty, M.C., Batsanov, A.S., Goeta, A.E. and Howard, J.A.K., Chem. Mater. 13, 1167 (2001).Google Scholar
9. Jung, G.Y., Wang, C., Pearson, C., Bryce, M.R., Samuel, I.D.W. and Petty, M.C., in Proceedings of the 45th SPIE Annual Meeting, San Diego, 4105, 307 (2000).Google Scholar
10. Miyamae, T., Yoshimura, D., Ishii, H., Ouchi, Y., Seki, K., Miyazaki, T., Koike, T. and Yamamoto, T., J. Chem. Phys. 103, 2738 (1995).Google Scholar
11. Aziz, H., Popovic, Z., Xie, S., Hor, A.M., Hu, N.X., Tripp, C. and Xu, G., Appl. Phys. Lett. 72, 756 (1998).Google Scholar
12. Schaer, M., Nhesch, F., Berner, D., Leo, W. and Zuppiroli, L., Adv. Func. Mater. 11, 116 (2001).Google Scholar
13. Lee, T.W., and Park, O.O., Adv. Mater. 12, 801 (2000).Google Scholar
14. Heeger, A. J. and Braun, D., US Patent, 5408109 (1995).Google Scholar
15. Gun, G. Y., PhD thesis, University of Durham, UK (2001).Google Scholar
16. McElvain, J., Antoniadis, H., Hueschen, M. R., Miller, J. N., Roitman, D. M., Sheats, J. R. and Moon, R. L., J. Appl. Phys. 80, 6002 (1996).Google Scholar
17. Logdlund, M., and Bredas, J.L., J. Chem. Phys. 101, 4357 (1994).Google Scholar
18. Hollars, C. W. and Dunn, R. C., Rev. Sci. Instr. 69, 1747 (1998).Google Scholar