Organic light-emitting diodes using a novel family of amorphous molecular materials containing an oligothiophene moiety as colour-tunable emitting materials

Abstract

A novel family of amorphous molecular materials containing an oligothiophene moiety with varying conjugation length function as thermally and morphologically stable, colour-tunable emitting materials for organic light-emitting diodes (LEDs). Tuning of the emission colour from light blue to orange is achieved by varying the conjugation length of the oligothiophene moiety. Double-layer organic LEDs that use this novel class of amorphous molecular materials as an emitting layer and tris(quinolin-8-olato)aluminium or 1,3,5-tris[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene as an electron-transport layer exhibit high performances.

References

1. C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett., 1987, 51, 913.
2. P. L. Burn, A. B. Holmes, A. Karft, D. D. C. Bradley, A. R. Brown, R. H. Friend and R. W. Gymer, Nature, 1992, 356, 47.
3. Y. Shirota, Proc. SPIE Int. Soc. Opt. Eng., 1997, 3148, 186 and references cited therein.
4. Y. Shirota, T. Kobata and N. Noma, Chem. Lett., 1989, 1145.
5. A. Higuchi, K. Ohnishi, S. Nomura, H. Inada and Y. Shirota, J. Mater. Chem., 1992, 2, 1109.
6. W. Ishikawa, H. Inada, H. Nakano and Y. Shirota, Mol. Cryst. Liq. Cryst., 1992, 211, 431.
7. W. Ishikawa, K. Noguchi, Y. Kuwabara and Y. Shirota, Adv. Mater., 1993, 5, 559.
8. H. Inada, K. Ohnishi, S. Nomura, A. Higuchi, H. Nakano and Y. Shirota, J. Mater. Chem., 1994, 4, 171.
9. Y. Shirota, Y. Kuwabara, H. Inada, T. Wakimoto, H. Nakada, Y. Yonemoto, S. Kawami and K. Imai, Appl. Phys. Lett., 1994, 65, 807.
10. Y. Kuwabara, H. Ogawa, H. Inada, N. Noma and Y. Shirota, Adv. Mater., 1994, 6, 677.
11. H. Inada, Y. Yonemoto, T. Wakimoto, K. Imai and Y. Shirota, Mol. Cryst. Liq. Cryst., 1996, 280, 331.
12. Y. Shirota, Y. Kuwabara, D. Okuda, R. Okuda, H. Ogawa, H. Inada, T. Wakimoto, H. Nakada, Y. Yonemoto, S. Kawami and K. Imai, J. Lumin., 1997, 72–74, 985.
13. K. Itano, T. Tsuzuki, H. Ogawa, S. Appleyard, M. R. Willis and Y. Shirota, IEEE Trans. Electron Devices, 1997, 44, 1218.
14. H. Ogawa, H. Inada and Y. Shirota, Macromol. Symp., 1997, 125, 171.
15. H. Ogawa, K. Ohnishi and Y. Shirota, Synth. Met., 1997, 91, 243.
16. T. Noda, I. Imae, N. Noma and Y. Shirota, Adv. Mater., 1997, 9, 239.
17. T. Noda, H. Ogawa, N. Noma and Y. Shirota, Appl. Phys. Lett., 1997, 70, 699.
18. T. Noda, H. Ogawa, N. Noma and Y. Shirota, Adv. Mater., 1997, 9, 720.
19. K. Katsuma and Y. Shirota, Adv. Mater., 1998, 10, 223.
20. K. Itano, H. Ogawa and Y. Shirota, Appl. Phys. Lett., 1998, 72, 636.
21. H. Ogawa, R. Okuda and Y. Shirota, Mol. Cryst. Liq. Cryst., 1998, 315, 489.
22. H. Ogawa, R. Okuda and Y. Shirota, Appl. Phys. A, 1998, 67, 599.
23. T. Noda and Y. Shirota, J. Am. Chem. Soc., 1998, 120, 9714.
24. T. Noda, H. Ogawa and Y. Shirota, Adv. Mater., 1999, 11, 283.
25. Y. Hamada, T. Sano, M. Fujita and T. Fujii, Chem. Lett., 1993, 905.
26. C. Hosokawa, H. Higashi, H. Nakamura and T. Kusumoto, Appl. Phys. Lett., 1995, 67, 3853.
27. J. Kido, M. Kimura and K. Nagai, Chem. Lett., 1996, 47.
28. J. Salbeck, N. Yu, J. Bauer, F. Weissörtel and H. Bestgen, Synth. Met., 1997, 91, 209.
29. K. Uchiyama, H. Akimichi, S. Hotta, H. Noge and H. Sakaki, Synth. Met., 1994, 63, 57.
30. F. Geiger, M. Stoldt, H. Schweizer, P. Bäuerle and E. Umbach, Adv. Mater., 1993, 5, 922.
31. G. Horowitz, P. Delannoy, H. Bouchriha, F. Deloffre, J.-L. Fave, F. Garnier, R. Hajlaoui, M. Heyman, F. Kouki, P. Valat, V. Wintgens and A. Yassar, Adv. Mater., 1994, 6, 752.
32. A. J. Pal, J. Paloheimo and H. Stubb, Appl. Phys. Lett., 1995, 67, 3909.
33. B. Servet, S. Ries, M. Trotel, P. Alnot, G. Horowitz and F. Garnier, Adv. Mater., 1993, 5, 461.
34. S. Hotta and K. Waragai, Adv. Mater., 1993, 5, 896.
35. D. Oelkrug, H.-J. Egelhaaf, D. R. Worrall and F. Wilkinson, J. Fluoresc., 1995, 5, 165.
36. R. S. Becker, J. Seixas de Melo, A. L. Maçanita and F. Elisei, J. Phys. Chem., 1996, 100, 18683.
37. D. Moses, J. Wang, A. Dogariu, D. Fichou and C. Videlot, Phys. Rev. B., 1999, 59, 7715.
38. A. Yassar, G. Horowitz, P. Valat, V. Wintgens, M. Hmyene, F. Deloffre, P. Srivastava, P. Lang and F. Garnier, J. Phys. Chem., 1995, 99, 9155.
39. R. N. Marks, R. H. Michel, W. Gebauer, R. Zamboni, C. Taliani, R. F. Mahrt and M. Hopmeier, J. Phys. Chem. B, 1998, 102, 7563.