Article
  • Improved Quantum Efficiency by Inserting Thin Insulating Langmuir-Blodgett Films in Polymer Electroluminescent Devices
  • Kim YE, Shin HS, Zyung T, Kim JJ
  • Langmuir-Blodgett 절연막을 삽입한 전기발광 고분자 소자의 발광효율 향상
  • 김은영, 신형식, 정태형, 김장주
Abstract
Quantum efficiency in a polymer electroluminescent device is significantly improved by inserting thin insulating layers with the thickness of the tunneling range. Four times higher quantum efficiency was obtained without the sacrifice of the operating voltage. The Langmuir-Blodgett (LB) technique was successfully applied to form the thin and uniform tunneling barriers using PMMA. The enhancement is supposed to be due to the lowering of the effective barrier height to electron injection while increasing the effective barrier to hole injection. The effects improved the balanced injection of both charges into the light emitting devices.

전기 발광 고분자 소자에서 터널링이 가능한 범위내의 얇은 절연막을 발광층과 음극전극 사이에 삽입함으로써 발광효율을 향상시켰다. 터널링 장벽은 Langmuir-Blodgett (LB) 기술을 이용하여 얇고 균일하게 형성된 PMMA절연층을 사용하였고, 이로써 발광효율이 구동전압의 증가없이 4배 이상 증가하였다. 이러한 발광효율의 향상은 유효 에너지 장벽이 정공주입에 대해서는 증가하는 반면에 전자주입에 대해서는 낮아지게 되어, 발광소자 내부로 주입되는 전하들이 균형을 이루기 때문인 것으로 생각된다.

Keywords: quantum efficiency; polymer; electroluminescent device; tunneling barrier; Langmuir-Boldgett films

References
  • 1. Burroughes JH, Bradley DDC, Brown AR, Marks RN, Mackay K, Friend RH, Burns PL, Holmes AB, Nature, 347, 539 (1990)
  •  
  • 2. Braun D, Heeger AJ, Appl. Phys. Lett., 58, 1982 (1991)
  •  
  • 3. Zhang C, Hoger S, Pakbaz K, Wudl F, Heeger AJ, J. Electron. Mater., 22, 413 (1993)
  •  
  • 4. Zyung T, Hwang DH, Kang IN, Shim HK, Hwang WY, Kim JJ, Chem. Mater., 7(8), 1499 (1995)
  •  
  • 5. Kang IN, Hwang DH, Shim HK, Zyung T, Kim JJ, Macromolecules, 29(1), 165 (1996)
  •  
  • 6. Tachelet W, Jacobs S, Ndayikengurukiye H, Geise HJ, Guner J, Appl. Phys. Lett., 64, 2364 (1994)
  •  
  • 7. Yang Z, Sokolik I, Karasz FE, Macromolecules, 26, 1188 (1993)
  •  
  • 8. Aratani S, Zhang C, Pakbaz K, Hoger S, Wudl F, Heeger AJ, J. Electron. Mater., 22, 745 (1994)
  •  
  • 9. Greenham NC, Moratti SC, Bradley DDC, Friend RH, Holmes AB, Nature, 365, 628 (1993)
  •  
  • 10. Zhang C, Hoger S, Pakbaz K, Kraabel B, Schmidt HW, Heeger AJ, Synth. Met., 62, 35 (1994)
  •  
  • 11. Ohmori Y, Morishima C, Fujii A, Yoshino K, Jpn. J. Appl. Phys., 33, L37 (1994)
  •  
  • 12. Kim JJ, Jung SD, Roh HS, Ha JS, Thin Solid Films, 244(1-2), 700 (1994)
  •  
  • 13. Jung SD, Kim JJ, Hwang WY, Zyung T, Mol. Cryst. Liq. Cryst., 247(-), 281 (1994)
  •  
  • 14. Jung SD, Kim JJ, Choi CK, HWAHAK KONGHAK, 32(3), 393 (1994)
  •  
  • 15. Brown AR, Greenham NC, Burroughes JH, Bradley DDC, Friend RH, Burns PL, Kraft A, Holmes AB, Chem. Phys. Lett., 200, 46 (1992)
  •  
  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2022 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1996; 20(3): 522-527

    Published online May 25, 1996