Transactions on Electrical and Electronic Materials

  • 제6권5호
  • /
  • Pages.221-224
  • /
  • 2005
  • /
  • 1229-7607(pISSN)
  • /
  • 2092-7592(eISSN)
한국전기전자재료학회 (The Korean Institute of Electrical and Electronic Material Engineers)
권호 표지
DOI QR코드

DOI QR Code

Improved Electron Injection on Organic Light-emitting Diodes with an Organic Electron Injection Layer

  • 발행 : 2005.10.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

To overcome of poor electron injection in organic light-emitting diodes (OLEDs) with Al cathode, a thin layer of inorganic insulating materials, like as LiF, is inserted between an Al cathode and an organic electron transport layer. Though the device, mentioned above, improves both turn on voltage and luminescent properties, it has some problems like as thickness restriction, less than 2 nm, and difficulty of deposition control. On the other hand, Li organic complex, Liq, is less thickness restrictive and easy to deposit and it also enhances the performance of devices. This paper reports the improved electron injection on OLEDs with another I A group metal complex, Potassium quinolate (Kq), as an electron injection material. OLEDs with organic complexes showed improved turn-on voltage and luminous efficiency which are remarkably improved compared to OLEDs with Al cathode. Especially, OLEDs with Kq have longer life time than OLEDs with Liq.

키워드

참고문헌

  1. C. W. Tang, S. A. VanSlkye, and C. H. Chen, 'Electroluminescence of doped organic thin films', J. Appl. Phys., Vol. 65, No.9, p. 3610, 1989
  2. M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thompson, and S. R. Forrest, 'Very high-efficiency green organic light-emitting devices based on electrophosphorescence', Appl. Phys. Lett., Vol. 75, No.1, p. 4, 1999
  3. J. H. Kim, S. P. Lee, J. S. Kim, Y. K. Kim, and S. H. Lee, 'Hole block effect on the organic electroluminescent device using Eu complex', Mol. Cryst. and Liq. Cryst., Vol. 371, p. 455, 2001
  4. J. H. Kim, Y. M. Kim, Y Ha, Y. K. Kim, and J. S. Kim, 'Electrical characteristics of green emitting phosphor $Ir(ppy)_3$ doped OLEDs', KIEE International Transactions on EA, Vol. 11C-3, p. 53, 2001
  5. J. H. Kim, E. J. Nam, S. Y Hong, B. O. Kim, S. M. Kim, S. S. Yoon, J. H. Suh, Y. Ha, and Y. K. Kim, 'Study on electrical characteristics of organic electrophophorescent devices based on new Ir complex', Materials Science and Engineering C, Vol. 24, p. 167, 2004
  6. C. W. Tang and S. A. VanSlkye, 'Organic electroluminescent diodes', Appl. Phys. Lett., Vol. 51, No. 12, p. 913, 1987
  7. G. E. Jabbour, Y. Kawabe, S. E. Shaheen, J. F. Wang, M. M. Morrell, B. Kippelen, and N. Peyghambarian, 'Highly efficient and bright organic electroluminescent devices with an aluminum cathode', Appl. Phys. Lett., Vol. 71, No. 13, p. 1762, 1997
  8. T. Mori, H. Fujikawa, S. Tokito, and Y. Taga, 'Electronic structure of 8-hydroxyquinoline aluminum/LiF/Al interface for organic electroluminescent device studied by ultraviolet photoelectron spectroscopy', Appl. Phys. Lett., Vol. 73, No. 19,p. 2763, 1998 https://doi.org/10.1063/1.122583
  9. M. Matsumera and Y. Jinde, 'Analysis of currentvoltage characteristics of organic light emitting diodes having a LiF/Al cathode and an Alhydroxyquinoline/diamine junction', Appl. Phys. Lett., Vol. 73, No. 20, p. 2872, 1998
  10. L. S. Hung, C. W. Tang, and M. G. Mason, 'Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode', Appl. Phys. Lett., Vol. 70, No.2, p. 152, 1997
  11. H. Heil, J. Steiger, S. Karg, M. Gastel, H. Ortner, H. Von Seggem, and M. Stopel, 'Mechanisms of injection enhancement in organic light-emitting diodes through an Al/LiF electrode', J. Appl. Phys., Vol. 89, No.1, p. 420, 2001
  12. M. G. Mason, C. W. Tang, L. S. Hung, P. Raychaudhuri, J. Madathil, D. J. Giesen, L. 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. Bredas, 'Interfacial chemistry of $Alq_3$ and LiF with reactive metals', J. Appl. Phys., Vol. 89, No.5, p. 2756, 2001 https://doi.org/10.1063/1.1339859
  13. H. Fujikawa, T. Mori, K. Noda, M. Ishii, S. Tokito, and W. Taga, 'Organic electroluminescent devices using alkaline-earth fluorides as an electron injection layer', J. Lumin., Vol. 87-89, p. 1177, 2000
  14. P. Jeffrey Hay, 'Theoretical studies of the ground and excited electronic states in cyclometalated phenylpyridine Ir(III) complexes using density functional theory', J. Phys. Chem. A, Vol. 106, No.8, p. 1634, 2002 https://doi.org/10.1021/jp0133743