Phosphorescence Quantum Efficiency and Intermolecular Interaction of Iridium(III) Complexes in Co-Deposited Films with Organic Semiconducting Hosts

Abstract

We accurately measured the absolute photoluminescence (PL) quantum efficiency (ηPL) of organic solid-state thin films by using an integrating sphere. We measured the ηPL of conventional organic materials used in organic light emitting diodes, such as a tris (8-quinolionolato)aluminum(III) complex (Alq3), and a phosphorescent 1.5mol%-/ac-tris(2-phenylpyridyl)iridium(in):4,4'-bis(carbazol-9-yl)-2,2'-biphenyl [Ir(ppy)3:CBP] co-deposited film. Alq3 and Ir(ppy)3:CBP showed a ηPL = 20 ± 1% and 97 ± 2%, which corresponded well to external electroluminescence efficiency using these materials. We also measured red emitting bis[2-(2'-benzothienyl)pyridinato-N,C3'] (acetylacetonato) iridium(III) [Btp2Ir(acac)] with CBP, and the blue complex, bis[(4,6-difluorophenyl)pyridinato -N,C2](picolinato)iridium(III) [FIrpic], with m-bis(N-carbazolyl)benzene. The maximum ηpl values for Btp2lr(acac), and FIrpic were 51±1% (at 1.4mol%), and 99±1% (1.2mol%), respectively. These results suggest that the ηel of red phosphorescent OLEDs using Btp2Ir(acac) as the dopant can be as high as 10%, and blue devices using FIrpic can reach the theoretical limit of 20%.

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References

  1. 1.

    C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett. 51, 913 (1987).

    CAS  Article  Google Scholar 

  2. 2.

    M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thomson and S. R. Forrest, Appl. Phys. Lett. 75, 4 (1999).

    CAS  Article  Google Scholar 

  3. 3.

    C. Adachi, M. A. Baldo, M. E. Thompson and S. R. Forrest, J. Appl. Phys. 90, 5048 (2001).

    CAS  Article  Google Scholar 

  4. 4.

    M. Ikai, S. Tokito, Y. Sakamoto, T. Suzuki and Y. Taga, Appl. Phys. Lett. 79, 156 (2001).

    CAS  Article  Google Scholar 

  5. 5.

    F. Hide, M. A. Diaz-García, B. J. Schwartz, M. R. Andersonn, Q. Pei, and A. J. Heeger, Science 273, 1833 (1996).

    CAS  Article  Google Scholar 

  6. 6.

    V. G. Kozlov, V. Bulovic, P. E. Burrows, and S. R. Forrest, Nature (London) 389, 362 (1997).

    CAS  Article  Google Scholar 

  7. 7.

    H. Yamamoto, T. Oyamada, H. Sasabe and C. Adachi, Appl. Phys. Lett. 84, 1401 (2004).

    CAS  Article  Google Scholar 

  8. 8.

    Y. Kawamura, H. Yamamoto, K. Goushi, H. Sasabe, C. Adachi and H. Yoshizaki, Appl. Phys. Lett. 84, 2724 (2004).

    CAS  Article  Google Scholar 

  9. 9

    T. Sakanoue, E. Fujiwara, R. Yamada and H. Tada, Appl. Phys. Lett. 84, 3037 (2004).

    CAS  Article  Google Scholar 

  10. 10

    S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, C. Adachi, P. E. Burrows, S. R. Forrest and M. E. Thompson, J. Am. Chem. Soc. 123, 4303 (2001).

    Article  Google Scholar 

  11. 11

    K. Goushi, Y. Kawamura, H. Sasabe and C. Adachi, Jpn. J. Appl. Phys. 43, L937 (2004).

    CAS  Article  Google Scholar 

  12. 12

    K. L. Eckerle, J. W. H. Vanable and V. R. Weidner, Appl. Opt. 15, 703 (1976).

    CAS  Article  Google Scholar 

  13. 13

    N. C. Greenham, I. D. W. Samuel, G. R. Hayes, R. T. Phillips, Y. A. R. R. Kessener, S. C. Moratti, A. B. Holms and R. H. Friend, Chem. Phys. Lett. 241, 89 (1995).

    CAS  Article  Google Scholar 

  14. 14

    H. Mattoussi, H. Murata, C. D. Merritt, Y. Iizumi, J. Kido and Z. H. Kafafi, J. Appl. Phys. 86, 4642 (1999).

    Google Scholar 

  15. 15

    Y. Kawamura, H. Sasabe and C. Adachi, Jpn. J. Appl. Phys, 43, 7729 (2004)

    CAS  Article  Google Scholar 

  16. 16.

    G. Gu, D. Z. Garbuzov, P. E. Burows, S. Venkatesh, S. R. Forrest and M. E. Thompson, Opt. Lett. 22, 396 (1997).

    CAS  Article  Google Scholar 

  17. 17.

    S. A. Vanslyke, P. S. Bryan and C. W. Tang, Ext. Abstr. p.195 (The 8th International Workshop on Inorg. and Org. Electroluminescence/EL96 Berlin).

  18. 18.

    Y. Kawamura, K. Goushi, J. Brooks, J. J. Brown, H. Sasabe and C. Adachi, Appl. Phys. Lett. (in press).

  19. 19

    C. Adachi, R. C. Kwong, P. Djurovich, V. Adamovich, M. A. Baldo, M. E. Thompson and S. R. Forrest, Appl. Phys. Lett. 79, 2082 (2001).

    CAS  Article  Google Scholar 

  20. 20

    R. Holmes, S. R. Forrest, Y.-J. Tung, R. C. Kwong, J. J. Brown, S. Garon and M. E. Thompson, Appl. Phys. Lett. 82, 2422 (2003).

    CAS  Article  Google Scholar 

Download references

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Correspondence to Yuichiro Kawamura.

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Kawamura, Y., Goushi, K., Brooks, J. et al. Phosphorescence Quantum Efficiency and Intermolecular Interaction of Iridium(III) Complexes in Co-Deposited Films with Organic Semiconducting Hosts. MRS Online Proceedings Library 846, 45 (2004). https://doi.org/10.1557/PROC-846-DD4.5

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