Effect of thickness of CuI hole injection layer on properties of organic light emitting diodes

Zenon Hotra, Pavlo Stakhira, Vladyslav Cherpak, Dmytro Volynyuk, Lesya Voznyak, Volodymyr Gorbulyk, Bogdan Tsizh

Abstract


We report the influence of the thickness of a copper iodide (CuI) hole injection layer (HIL) on the performance of organic light-emitting diodes (OLEDs) with tris-8-hydroxyquinoline aluminum (Alq3) active layer and aluminum cathode layer. The investigation of structural and morphological properties of thermally evaporated CuI thin films indicates that they are amorphous. OLEDs with the ITO/CuI/Alq3/poly(ethylene glycol) dimethyl ether/Al structures were fabricated and current density-voltage, luminance-voltage and current efficiency-current density were analyzed. The maximal luminescence current efficiency is obtained for the devices with a CuI thickness of 12nm.

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References:
  1. W. Brütting, S. Berleb, A.G. Mückl, "Device physics of organic light-emitting diodes based on molecular materials", Organic Electronics 2, 1 (2001).CrossRef
  2. H. Kubota et al., "Organic LED full color passive-matrix display", Journ. of Lumin. 87-89, 56 (2000).CrossRef
  3. J. Kido,, "Organic displays", Phys. World 12, 27 (1999).DirectLink
  4. M. Stossel, J. Staudigel, F. Steuber, J. Simmer, A. Winnacke,, "Impact of the cathode metal work function on the performance of vacuum-deposited organic light emitting-devices", Appl. Phys. A: Mater. Sci. Process 68, 387 (1999).CrossRef
  5. T.M. Brown, R.H. Friend, I.S. Millard, P.J. Lacey, J.H. Burroughes, F. Cacialli, "Efficient electron injection in blue-emitting polymer light-emitting diodes with LiF/Ca/Al cathodes ", Appl. Phys. Lett. 79, 174 (2001).CrossRef
  6. B. Choi, H. Yoon, H.H. Lee., "Surface treatment of indium tin oxide by SF6 plasma for organic light-emitting diodes ", Appl. Phys. Lett. 76, 412 (2000).CrossRef
  7. K. Fehse, G. Schwartz, K. Walzer, K. Leoa,, "Combination of a polyaniline anode and doped charge transport layers for high-efficiency organic light emitting diodes", J. Appl. Phys. 101, 124509 (2007).CrossRef
  8. N. Drolet, S. Beaupré, J.F. Morin, Y. Tao, M. Leclerc, "Red–green–blue light-emitting diodes containing fluorene-based copolymers", J. Optic Pure Appl Optic 4, S252 (2002).CrossRef
  9. B.D. Chin,, "Role of the polymeric hole injection layer on the efficiency and stability of organic light emitting diodes with small molecular emitters", J Phys D: Appl Phys. 41, 215104 (2008).CrossRef
  10. S.A. Van Slyke, C.H. Chen, C.W. Tang., "Organic electroluminescent devices with improved stability", Appl. Phys. Lett. 69, 2160 (1996).CrossRef
  11. Y. Shen, D.B. Jacobs, G.G. Malliaras, G. Koley, M.G. Spencer, A. Ioannidis,, "Modification of Indium Tin Oxide for Improved Hole Injection in Organic Light Emitting Diodes", Adv. Mater 13, 1234 (2001).CrossRef
  12. C. Qiu, Z. Xie, H. Chen, M. Wong, H.S. Kwok, "Comparative study of metal or oxide capped indium–tin oxide anodes for organic light-emitting diodes", J. Appl. Phys. 93, 3253 (2003).CrossRef
  13. P.Y. Stakhira, V.V. Cherpak, "The properties of heterojunction based on CuI/pentacene/Al", Vacuum 83, 1129 (2009).CrossRef
  14. P. Stakhira, V. Cherpak, D. Volynyuk, F. Ivastchyshyn, Z. Hotra, V. Tataryn, G. Luka, Thin Solid Films. 518, 7016 (2010)., "Characteristics of organic light emitting diodes with copper iodide as injection layer".CrossRef
  15. P.M. Sirimanne, T. Soga, M. Kunst,"Observation of microwave conductivity in copper iodide films and relay effect in the dye molecules attached to CuI photocathode", J. Solid. State Chem. 178, 3010 (2005).CrossRef
  16. T.H. Lee et al., Adv. Funct. Mater. 18, 3036 (2008), "Organic-Oxide Cathode Buffer Layer in Fabricating High-Performance Polymer Light-Emitting Diodes", .CrossRef
  17. T.F. Stoica et al., "Characterization of ITO thin films prepared by spinning deposition starting from a sol-gel process", J. Optoelectron. Adv. Mater. 2, 684 (2000).DirectLink
  18. T. Maruyama, K. Fukui, "Indium-tin oxide thin films prepared by chemical vapor deposition", J. Appl. Phys. 70, 3848 (1991).CrossRef
  19. Y. Shirota et al., "Multilayered organic electroluminescent device using a novel starburst molecule, 4,4′,4″?tris(3?methylphenylphenylamino)triphenylamine, as a hole transport material", Appl. Phys. Lett. 65, 807 (1994).CrossRef
  20. Ch. Jonda, A.B.R. Mayer, U. Stolz, A. Elschner, A. Karbach,, "Surface roughness effects and their influence on the degradation of organic light emitting devices ", J. Mater. Sci. 35, 5645 (2000).CrossRef
  21. A.V. Kukhto,, "Electroluminescence of Thin Films of Organic Compounds (Review)", J. Appl. Spectrosc. 70, 165 (2003).CrossRef
  22. P.M. Sirimanne, M. Rusop, T. Shirata, T. Soga, T. Jimbo,,"Characterization of transparent conducting CuI thin films prepared by pulse laser deposition technique", Chem. Phys. Lett. 366, 485 (2002).CrossRef
  23. J. Shinar, Organic light-emitting devices: a survey (New York, Springer 2004).

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Photonics Letters of Poland - A Publication of the Photonics Society of Poland
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ISSN: 2080-2242