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Journal of Display Technology

Journal of Display Technology

| A JOINT IEEE/OSA PUBLICATION

  • Vol. 3, Iss. 2 — Jun. 1, 2007
  • pp: 193–199

Efficient White OLEDs Employing Phosphorescent Sensitization

Chih-Hao Chang, Yin-Jui Lu, Chih-Che Liu, Yung-Hui Yeh, and Chung-Chih Wu

Journal of Display Technology, Vol. 3, Issue 2, pp. 193-199 (2007)


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Abstract

We have investigated white-emitting organic light-emitting devices (WOLEDs) making use of both blue-phosphor-sensitized orange-red fluorescence and the residual blue phosphorescence. By carefully adjusting the concentrations the phosphor and the fluorophore in the emitting layer and choosing the carrier-transport layers in the device structure, WOLEDs containing a single phosphor-sensitized emitting layer (type-I devices) can give colors close to the equal-energy white (0.33, 0.33), CRI up to 75, and efficiencies up to (10%, 23 cd/A, 13.4 lm/W). Furthermore, by doping a green phosphor into the poorly emitting electron-transport layer (type-II devices) to recycle excitons formed there, the EL efficiencies can be further enhanced up to (12.1%, 35.3 cd/A, 23.9 lm/W). In both types of devices, the phosphor sensitization reduces population of triplet excitons in the emitting region and substantially mitigates the efficiency roll-off with the driving current or brightness that is often observed in all-phosphor OLEDs. At the brightness of 1000 cd/m2, both types of devices retain quantum and cadmium per ampere (cd/A) efficiencies similar to their peak values.

© 2007 IEEE

Citation
Chih-Hao Chang, Yin-Jui Lu, Chih-Che Liu, Yung-Hui Yeh, and Chung-Chih Wu, "Efficient White OLEDs Employing Phosphorescent Sensitization," J. Display Technol. 3, 193-199 (2007)
http://www.opticsinfobase.org/jdt/abstract.cfm?URI=jdt-3-2-193


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References

  1. U.S. Gov. Printing Office, U. S. Dep. of EnergyWashingtonDCNational Lighting Inventory and Energy Consumption Estimate (2001)1.
  2. U.S. Gov. Printing Office, U. S. Dep. of EnergyWashingtonDCIlluminating the Challenges: Solid State Lighting Program Planning Workshop Report (2003).
  3. J. Kido, M. Kimura, K. Nagai, Science (, 1994) pp. 1332-1334.
  4. R. H. Jordan, A. Dodabalapur, M. Strukelj, T. M. Miller, "White organic electroluminescence devices," Appl. Phys. Lett. 68, 1192-1194 (1996).
  5. R. S. Deshpande, V. Bulovic', S. R. Forrest, "White-light-emitting organic electroluminescent devices based on interlayer sequential energy transfer," Appl. Phys. Lett. 75, 888-890 (1999).
  6. F. Steuber, J. Staudigel, M. Stössel, J. Simmerer, A. Winnacker, H. Spreitzer, F. Weissörtel, J. Salbeck, "White light emission from organic LEDs utilizing spiro compounds with high-temperature stability," Adv. Mater. 12, 130-133 (2000).
  7. C. W. Ko, Y. T. Tao, "Bright white organic light-emitting diode," Appl. Phys. Lett. 79, 4234-4236 (2001).
  8. B. W. D'Andrade, M. E. Thompson, S. R. Forrest, "Controlling exciton diffusion in multilayer white phosphorescent organic light emitting devices," Adv. Mater. 14, 147-151 (2002).
  9. S. Tokito, T. Iijima, T. Tsuzuki, F. Sato, "High-efficiency white phosphorescent organic light-emitting devices with greenish-blue and red-emitting layers," Appl. Phys. Lett. 83, 2459-2461 (2003).
  10. B. W. D'Andrade, R. J. Holmes, S. R. Forrest, "Efficient organic electrophosphorescent white-light-emitting device with a triple doped emissive layer," Adv. Mater. 16, 624-628 (2004).
  11. C. Adachi, M. A. Baldo, M. E. Thompson, S. R. Forrest, "Nearly 100% internal phosphorescence efficiency in an organic light emitting device," J. Appl. Phys. 90, 5048-5051 (2001).
  12. M. A. Baldo, M. E. Thompson, S. R. Forrest, "High-efficiency fluorescent organic light-emitting devices using a phosphorescent sensitizer," Nature (London) 403, 750-753 (2000).
  13. B. W. D'Andrade, M. A. Baldo, C. Adachi, J. Brooks, M. E. Thompson, S. R. Forrest, "High-efficiency yellow double-doped organic light-emitting devices based on phosphor-sensitized fluorescence," Appl. Phys. Lett. 79, 1045-1047 (2001).
  14. G. Lei, L. Wang, Y. Qiu, "Blue phosphorescent dye as sensitizer and emitter for white organic light-emitting diodes," Appl. Phys. Lett. 85, 5403-5405 (2004).
  15. Y. Kawamura, K. Goushi, J. Brooks, J. J. Brown, H. Sasabe, C. Adachi, "100% phosphorescence quantum efficiencies of Ir(III) complexes in organic semiconductor films," Appl. Phys. Lett. 86, 071104 (2005).
  16. R. J. Holmes, S. R. Forrest, Y.-J. Tung, R. C. Kwong, J. J. Brown, S. Garon, M. E. Thompson, "Blue organic electrophosphorescence using exothermic host-guest energy transfer," Appl. Phys. Lett. 82, 2422-2424 (2003).
  17. M.-H. Tsai, H.-W. Lin, H.-C. Su, T.-H. Ke, C.-C. Wu, F.-C. Fang, Y.-L. Liao, K.-T. Wong, C.-I. Wu, "Highly efficient organic blue electrophosphorescent devices based on 3,6-Bis(triphenylsilyl)carbazole as the host material," Adv. Mater. 18, 1216-1220 (2006).
  18. T.-C. Chao, Y.-T. Lin, C.-Y. Yang, T.-H. Hung, H.-C. Chou, C.-C. Wu, K.-T. Wong, "Highly efficient UV organic light-emitting devices based on bi(9,9-diarylfluorene)s," Adv. Mater. 17, 992-996 (2005).
  19. C.-C. Wu, Y.-T. Lin, K.-T. Wong, R.-T. Chen, Y.-Y. Chien, "Efficient organic blue-light-emitting devices with double confinement on terfluorenes with ambipolar carrier transport properties," Adv. Mater. 16, 61-65 (2004).
  20. V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, S. R. Forrest, "Bright, saturated, red-to-yellow organic light emitting devices based on polarization-induced spectral shifts," Chem. Phys. Lett. 287, 453-460 (1998).
  21. C. F. Madigan, V. Bulović, "Solid state salvation in amorphous organic thin films," Phys. Rev. Lett. 91, 247403-1-247403-4 (2003).
  22. B. W. D'Andrade, S. R. Forrest, "White organic light-emitting devices for solid-state lighting," Adv. Mater. (2004) pp. 1585-1595.
  23. Y. Sun, N. C. Giebink, H. Kanno, B. Ma, M. E. Thompson, S. R. Forrest, "Management of singlet and triplet excitons for efficient white organic light-emitting devices," Nature (London) 440, 908-912 (2006).

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