DOI QR코드

DOI QR Code

Effects of BCP Electron Transport Layer Thickness on the Efficiency and Emission Characteristics of White Organic Light-Emitting Diodes

BCP 전자수송층 두께가 백색 OLED의 효율 및 발광 특성에 미치는 영향

  • Seo, Yu-Seok (Department of Materials Engineering, Soonchunhyang University) ;
  • Moon, Dae-Gyu (Department of Materials Engineering, Soonchunhyang University)
  • 서유석 (순천향대학교 신소재공학과) ;
  • 문대규 (순천향대학교 신소재공학과)
  • Received : 2013.10.29
  • Accepted : 2013.11.26
  • Published : 2014.01.01

Abstract

We have fabricated white organic light-emitting diodes (OLEDs) using several thicknesses of electron-transport layer. The multi-emission layer structure doped with red and blue phosphorescent guest emitters was used for achieving white emission. 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was used as an electron-transport layer. The thickness of BCP layer was varied to be 20, 55, and 120 nm. The current efficiency, emission and recombination characteristics of multi-layer white OLEDs were investigated. The BCP layer thickness variation results in the shift of emission spectrum due to the recombination zone shift. As the BCP layer thickness increases, the recombination zone shifts toward the electron-transport layer/emission-layer interface. The white OLED with a 55 nm thick BCP layer exhibited a maximum current efficiency of 40.9 cd/A.

References

  1. C. W. Tang and S. A. Vanslyke, Appl. Phys. Lett., 51, 913 (1987). https://doi.org/10.1063/1.98799
  2. B. W. D'Andrade and S. R. Forrest, Adv. Mater., 16, 1585 (2004). https://doi.org/10.1002/adma.200400684
  3. M. A. Baldo, D. F. O’Brien, Y. You, A. Shoustikov, S. Sibley, M. E. Thompson, and S. R. Forrest, Nature, 395, 151 (1998). https://doi.org/10.1038/25954
  4. B. W. D'Andrade, R. J. Holmes, and S. R. Forrest, Adv. Mater., 16, 624 (2004). https://doi.org/10.1002/adma.200306670
  5. B. W. D'Andrade, M. E. Thompson, and S. R. Forrest, Adv. Mater., 14, 147 (2002). https://doi.org/10.1002/1521-4095(20020116)14:2<147::AID-ADMA147>3.0.CO;2-3
  6. Y. Sun and S. R. Forrest, Appl. Phys. Lett., 91, 263503 (2007). https://doi.org/10.1063/1.2827178
  7. H. Kanno, R. J. Holmes, Y. Sun, S. Kena-Cohen, and S. R. Forrest, Adv. Mater., 18, 339 (2006). https://doi.org/10.1002/adma.200501915
  8. M. A. Baldo, C. Adachi, and S. R. Forrest, Phys. Rev., B62, 10967 (2000).
  9. Y. S. Seo and D. G. Moon, J. Phys. D: Appl. Phys., 43, 305101 (2010). https://doi.org/10.1088/0022-3727/43/30/305101
  10. V. Maiorano, E. Perrone, S. Carallo, A. Biasco, P. P. Pompa, R. Cingolani, A. Croce, R. Blyth, and J. Thompson, Synth. Met., 151, 147 (2005). https://doi.org/10.1016/j.synthmet.2005.03.022
  11. A. Endo and C. Adachi, Chem. Phys. Lett., 483, 224 (2009). https://doi.org/10.1016/j.cplett.2009.10.064
  12. C. Adachi, R. C. Kwong, P. Djurovich, V. Adamovich, M. A. Baldo, and S. R. Forrest, Appl. Phys. Lett., 79, 2082 (2001). https://doi.org/10.1063/1.1400076
  13. L. S. Hung and C. W. Tang, Appl. Phys. Lett., 74, 3209 (1999). https://doi.org/10.1063/1.124107
  14. G. G. Malliaras and J. C. Scott, J. Appl. Phys., 83, 5399 (1998). https://doi.org/10.1063/1.367369