Journal of the Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회논문지)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Effects of Emission Layer Thickness on the Efficiency of Blue Phosphorescent Organic Light Emitting Diodes with Triple Layer Structure

발광층 두께가 삼층 구조 청색 인광 OLED의 효율 특성에 미치는 영향

  • 서유석 (순천향대학교 디스플레이신소재공학과) ;
  • 문대규 (순천향대학교 디스플레이신소재공학과)
  • Published : 2010.02.01
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Abstract

We have fabricated simple triple-layer blue-emitting phosphorescent organic light emitting diodes (OLEDs) using different thicknesses of N,N'-dicarbazolyl-3,5-benzene (mCP) host layers doped with bis[(4,6-di-fluorophenyl)-pyridinate-N,$C^{2'}$]picolmate (FIrpic) guest materials. The thicknesses of mCP:FIrpic layers were 5, 10, and 30 nm. Driving voltage, current and power efficiencies were investigated. The current efficiency was higher in the 10 nm thick mCP:FIrpic device, resulting from the better electron-hole balance. The device with 10 nm mCP:FIrpic layer exhibited the maximum current efficiency of 22.5 cd/A and power efficiency of 7.4 lm/W at a luminance of 1000 cd/$m^2$.

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References

  1. C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes", Appl. Phys. Lett., Vol. 51, No. 12, p. 913, 1987. https://doi.org/10.1063/1.98799
  2. 정동희, 김상걸, 홍진웅, 이준웅, 김태완, “버퍼층과 음전극에 따른 유기 발광 소자의 전기적 특성과 발광 효율”, 전기전자재료학회논문지, 16권, 5호, p. 409, 2003. https://doi.org/10.4313/JKEM.2003.16.5.409
  3. M. A. Baldo, D. F. O'Brien, Y. You, A. Shoustikov, S. Sibley, M. E. Thompson, and S. R. Forrest, "Highly efficient phosphorescent emission from organic electroluminescence", Nature, Vol. 395, p. 151, 1998. https://doi.org/10.1038/25954
  4. C. Adachi, R. C. Kwong, P. Djurovich, V. Adamovich, M. A. Baldo, M. E. Thompson, and S. R. Forrest, "Endothermic energy transfer: A mechanism for generating very efficient high-energy phosphorescent emission in organic crystals", Appl. Phys. Lett., Vol. 79, No. 13, p. 2082, 2001. https://doi.org/10.1063/1.1400076
  5. R. J. Holmes, S. R. Forrest, Y. J. Tung, R. C. Kwong, J. J. Brown, S. Garon, and M. E. Thompson, "Blue electrophosphorescence using exothermic host-guest energy transfer", Appl. Phys. Lett., Vol. 82, No. 15, p. 2422, 2003. https://doi.org/10.1063/1.1568146
  6. D. R. Whang, Y. You, S. H. Kim, W. I. Jeong, Y. S. Park, J. J. Kim, and S. Y. Park, “A highly efficient wide-band-gap-host material for blue electrophosphorescent lightemitting devices", Appl. Phys. Lett., Vol. 91, p. 233501, 2007. https://doi.org/10.1063/1.2821116
  7. H. Kanno, R. J. Holmes, Y. Sun, S. K. Cohen, and S. R. Forrest, "White stacked electrophosphorescent organic light-emitting devices employing MoO3 as a chargegeneration layer", Adv. Mater., Vol. 18, p. 339, 2006. https://doi.org/10.1002/adma.200501915
  8. J. Lee, N. Chopra, S. H. Eom, Y. Zheng, J. Xue, F. So, and J. Shi, "Effects of triplet energies and transporting properties of carrier transporting materials on blue phosphorescent organic light emitting devices", Appl. Phys. Lett., Vol. 93, p. 123306, 2008. https://doi.org/10.1063/1.2978235
  9. I. G. Hill and A. Kahn, "Organic semiconductor heterointerfaces containing bathocuprine", J. Appl. Phys., Vol. 86, No. 8, p. 4515, 1999. https://doi.org/10.1063/1.371395
  10. Y. Li, K. Fung, Z. Xie, S. T. Lee, L. S. Hung, and J. Shi, "An efficient pure blue organic light-emitting device with low driving voltages", Adv. Mater., Vol. 14, No. 18, p. 1317, 2002. https://doi.org/10.1002/1521-4095(20020916)14:18<1317::AID-ADMA1317>3.0.CO;2-S
  11. M. A. Baldo, C. Adachi, and S. R. Forrest, "Transient analysis of organic electrophosphorescence II. transient analysis of triplet-triplet annihilation", Phys. Rev. B, Vol. 62, No. 16, p. 10967, 2000. https://doi.org/10.1103/PhysRevB.62.10967
  12. K. Goushi, R. Kwong, J. J. Brown, H. Sasabe, and C. Adachi, "Triplet exciton confinement and unconfinement by adjacent hole-transport layers", J. Appl. Phys., Vol. 95, No. 12, p. 7798, 2004. https://doi.org/10.1063/1.1751232