High-efficiency, low-voltage phosphorescent organic light-emitting diode devices with mixed host
J. Appl. Phys. 104, 094501 (2008); doi:10.1063/1.3000046
Published 4 November 2008
You are not logged in to this journal. Log in
We report high-efficiency, low-voltage phosphorescent green and blue organic light-emitting diode (PHOLED) devices using mixed-host materials in the light-emitting layer (LEL) and various combinations of electron-injecting and electron-transporting layers. The low voltage does not rely on doping of the charge-transport layers. The mixed LEL architecture offers significantly improved efficiency and voltage compared to conventional PHOLEDs with neat hosts, in part by loosening the connection between the electrical band gap and the triplet energy. Bulk recombination in the LEL occurs within ~10 nm of the interface with an electron-blocking layer. A “hole-blocking layer” need not have hole- or triplet-exciton-blocking properties. Optical microcavity effects on the spectrum and efficiency were used to locate the recombination zone. The effect of layer thickness on drive voltage was used to determine the voltage budget of a typical device. The behavior of undoped devices was investigated, and the electroluminescence is attributed to an exciplex of the two host materials. Electrically detected electron paramagnetic resonance was used to study the behavior of doped and undoped PHOLED devices from 20 to 200 K, which largely mimics the behavior of the same devices at room temperature.
©2008 American Institute of Physics
| History: | Received 18 April 2008; accepted 25 August 2008; published 4 November 2008 |
| Permalink: |
http://link.aip.org/link/?JAPIAU/104/094501/1 |
REFERENCES (62)
For access to fully linked references, you need to log in.
For access to fully linked references, you need to Log in.
- M. A. Baldo, D. F. O'Brien, Y. You, A. Shoustikov, S. Sibley, M. E. Thompson, and S. R. Forrest,
Nature (London) 395, 151 (1998) . - D. Tanaka, H. Sasabe, Y. -J. Li, S. -J. Su, T. Takeda, and J. Kido,
Jpn. J. Appl. Phys., Part 2 46, L10 (2007) . - S. Watanabe, N. Ide, and J. Kido,
Jpn. J. Appl. Phys., Part 1 46, 1186 (2007) . - V. I. Adamovich, S. R. Cordero, P. I. Djurovich, A. Tamayo, M. E. Thompson, B. W. D'Andrade, and S. R. Forrest,
Org. Electron. 4, 77 (2003) . - G. He, O. Schneider, D. Qin, X. Zhou, M. Pfeiffer, and K. Leo, J. Appl. Phys. 95, 5773 (2004).
- M. Hack, M. S. Weaver, V. Adamovich, R. C. Kwong, M. H. Lu, and J. J. Brown,
Proc. SPIE 5961, 596102 (2005) . - K. Goushi, R. Kwong, J. J. Brown, H. Sasabe, and C. Adachi, J. Appl. Phys. 95, 7798 (2004).
- Y. Shirota and H. Kageyama,
Chem. Rev. (Washington, D.C.) 107, 953 (2007) . - G. He, K. Walzer, M. Pfeiffer, K. Leo, R. Pudzich, and J. Salbeck,
Proc. SPIE 5519, 42 (2004) . - G. He, M. Pfeiffer, K. Leo, M. Hofmann, J. Birnstock, R. Pudzich, and J. Salbeck, Appl. Phys. Lett. 85, 3911 (2004).
- A. B. Chwang, R. Kwong, and J. J. Brown,
Proc. SPIE 4800, 55 (2003) . - G. Lei, L. Wang, and Y. Qui,
Jpn. J. Appl. Phys., Part 2 43, L1226 (2004) . - V. V. Jarikov, R. H. Young, J. R. Vargas, C. T. Brown, K. P. Klubek, and L. -S. Liao, J. Appl. Phys. 100, 094907 (2006).
- C. Adachi, R. Kwong, and S. R. Forrest,
Org. Electron. 2, 37 (2001) . - K. P. Klubek and C. W. Tang, Proceedings of the ELN 2004 12th International Workshop on Inorganic and Organic Electroluminescence, 2004 (unpublished), p. 13.
- J. -H. Lee, H. -H. Tsai, M. -K. Leung, C. -C. Yang, and C. -C. Chao, Appl. Phys. Lett. 90, 243501 (2007).
- R. J. Holmes, B. W. D'Andrade, S. R. Forrest, X. Ren, J. Li, and M. E. Thompson, Appl. Phys. Lett. 83, 3818 (2003).
- Z. Popovic, H. Aziz, C. P. Tripp, N. -X. Hu, A. M. Hor, and G. Xu,
Proc. SPIE 3476, 68 (1998) . - Z. Popovic and H. Aziz,
IEEE J. Sel. Top. Quantum Electron. 8, 362 (2002) . - T. K. Hatwar, C. T. Brown, L. Cosimbescu, M. L. Ricks, J. P. Spindler, W. Begley, and J. R. Vargas,
Proc. SPIE 5519, 1 (2004) . - R. Kwong, M. G. Hack, T. Zhou, J. J. Brown, and T. D. Ngo, U.S. Patent No. 6,803,720 B2 (2004).
- T. D. Anthopoulos, J. P. J. Markham, E. B. Namdas, I. D. W. Samuel, S. -C. Lo, and P. L. Burn, Appl. Phys. Lett. 82, 4824 (2003).
- S. H. Kim, J. Jang, and J. Y. Lee, Appl. Phys. Lett. 91, 083511 (2007).
- S. H. Kim, J. Jang, K. S. Yook, and J. Y. Lee, Appl. Phys. Lett. 92, 023513 (2008).
- C. T. Brown, J. C. Deaton, D. W. Place, M. E. Kondakova, and D. Y. Kondakov,
SID Int. Symp. Digest Tech. Papers 36, 850 (2005) . - M. E. Kondakova, J. C. Deaton, D. Y. Kondakov, T. D. Pawlik, R. H. Young, C. T. Brown, and D. J. Giesen,
SID Int. Symp. Digest Tech. Papers 38, 837 (2007) . - J. C. Deaton, D. W. Place, C. T. Brown, M. Rajeswaran, and M. E. Kondakova,
Inorg. Chim. Acta 361, 1020 (2008) . - L. S. Hung, L. R. Zheng, and M. G. Mason, Appl. Phys. Lett. 78, 673 (2001).
- L. S. Hung, C. W. Tang, and M. G. Mason, Appl. Phys. Lett. 70, 152 (1997).
- M. G. Mason, C. W. Tang, L. -S. Hung, P. Raychaudhuri, J. Madathil, D. J. Giesen, Y. Yan, Q. T. Le, Y. Gao, S. -T. Lee, L. S. Liao, L. F. Cheng, W. R. Salaneck, D. A. dos Santos, and J. L. Brédas, J. Appl. Phys. 89, 2756 (2001).
- G. G. Malliaras, J. R. Salem, P. J. Brock, and J. C. Scott, J. Appl. Phys. 84, 1583 (1998).
- R. N. Marks, J. J. M. Halls, D. D. C. Bradley, R. H. Friend, and A. B. Holmes,
J. Phys.: Condens. Matter 6, 1379 (1994) . - B. W. D'Andrade, S. Datta, S. R. Forrest, P. Djurovich, E. Polikarpov, and M. E. Thompson,
Org. Electron. 6, 11 (2005) . - A. P. Marchetti, private communication (August 6, 2001).
- A. P. Marchetti and D. R. Kearns,
J. Am. Chem. Soc. 89, 768 (1967) . - J. B. Birks, Photophysics of Aromatic Molecules (Wiley, New York, 1970), Sec. 4.2.
- S. L. Murov, I. Carmichael, and G. L. Hug, Handbook of Photochemistry, 2nd ed. (Dekker, New York, 1993).
- A. D. Becke, Phys. Rev. A 38, 3098 (1988).
- P. J. Stephens, F. J. Devlin, C. F. Chabalowski, and M. J. Frisch,
J. Phys. Chem. 98, 11623 (1994) . - M. J. Frisch, G. W. Trucks, H. B. Schlegel et al., GAUSSIAN 98, Revision A9, Gaussian, Inc., Pittsburgh, PA, 1998.
- M. J. Frisch, G. W. Trucks, H. B. Schlegel et al., GAUSSIAN 03, Revision B.05, Gaussian, Inc., Pittsburgh, PA, 2003.
- PQS, 3.1 ed., Parallel Quantum Solutions, 2013 Green Acres Road, Fayetteville, Arkansas 72703, 2004.
- Jaguar 5.5, release 11, Schrödinger, Inc., Portland, Oregon, 2003.
- P. J. Hay and W. R. Wadt, J. Chem. Phys. 82, 299 (1985).
- M. M. Francl, W. J. Petro, W. J. Hehre, J. S. Binkley, M. S. Gordon, D. J. DeFrees, and J. A. Pople, J. Chem. Phys. 77, 3654 (1982).
- W. J. Hehre, R. Ditchfield, and J. A. Pople, J. Chem. Phys. 56, 2257 (1972).
- R. E. Easton, D. J. Giesen, A. Welch, C. J. Cramer, and D. G. Truhlar,
Theor. Chim. Acta 93, 281 (1996) . - C. P. Andrieux, A. Le Gorande, and J. -M. Savéant,
J. Am. Chem. Soc. 114, 6892 (1992) . - H. D. Burrows, M. Fernandes, J. Seixas de Melo, A. P. Monkman, and S. Navaratnam,
J. Am. Chem. Soc. 125, 15310 (2003) . - M. Cölle, C. Gärditz, and M. Braun, J. Appl. Phys. 96, 6133 (2004).
- T. Watanabe, K. Nakamura, S. Kawami, Y. Fukuda, T. Tsuji, T. Wakimoto, and S. Miyaguchi,
Proc. SPIE 4105, 175 (2001) . - V. V. Jarikov, D. Y. Kondakov, and C. T. Brown, J. Appl. Phys. 102, 104908 (2007).
- R. C. Kwong, M. R. Nugent, L. Michalski, T. Ngo, K. Rajan, Y. -J. Tung, M. S. Weaver, T. X. Zhou, M. Hack, M. E. Thompson, S. R. Forrest, and J. J. Brown, Appl. Phys. Lett. 81, 162 (2002).
- M. Pfeiffer, K. Leo, X. Zhou, J. S. Huang, M. Hofmann, A. Werner, and J. Blochwitz-Nimoth,
Org. Electron. 4, 89 (2003) . - S. Berleb, W. Brütting, and G. Paasch,
Org. Electron. 1, 41 (2000) . - D. Y. Kondakov, J. R. Sandifer, C. W. Tang, and R. H. Young, J. Appl. Phys. 93, 1108 (2003).
- J. D. Jackson, Classical Electrodynamics, 3rd ed. (Wiley, New York, 1999), Sec. 6.6.
- O. H. Crawford, J. Chem. Phys. 89, 6017 (1988).
- K. B. Kahen, Appl. Phys. Lett. 78, 1649 (2001).
- V. V. Jarikov, J. Appl. Phys. 100, 014901 (2006).
- G. Li, C. H. Kim, P. A. Lane, and J. Shinar, Phys. Rev. B 69, 165311 (2004).
- C. F. O. Graeff, G. B. Silva, F. Nuesch, and L. Zuppiroli,
Eur. Phys. J. E 18, 21 (2005) .







