The Orientation of Ir Complexes Doped in Organic Amorphous Layers

  • Chang-Ki Moon
Part of the Springer Theses book series (Springer Theses)


Molecular orientation in organic semiconductor is an important factor influencing electrical and optical properties [1]. In OLEDs, emitting dipole orientation (EDO) is directly related to the outcoupling efficiency of the light. Therefore, employing horizontally oriented emitter is one of the effective methods to enhancing the outcoupling efficiency of OLEDs [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]. Recent researches have focused on molecular structure of emitters [5, 8, 10, 12, 13] or changing deposition temperature to understand the preferred EDO of emitters doped in host layers [14, 15].


  1. 1.
    Yokoyama D (2011) Molecular orientation in small-molecule organic light-emitting diodes. J Mater Chem 21:19187. Scholar
  2. 2.
    Flämmich M et al (2011) Oriented phosphorescent emitters boost OLED efficiency. Org Electron 12:1663–1668CrossRefGoogle Scholar
  3. 3.
    Liehm P et al (2012) Comparing the emissive dipole orientation of two similar phosphorescent green emitter molecules in highly efficient organic light-emitting diodes. Appl Phys Lett 101:253304ADSCrossRefGoogle Scholar
  4. 4.
    Kim S-Y et al (2013) Organic light-emitting diodes with 30% external quantum efficiency based on a horizontally oriented emitter. Adv Func Mater 23:3896–3900. Scholar
  5. 5.
    Kim KH et al (2014) Phosphorescent dye-based supramolecules for high-efficiency organic light-emitting diodes. Nat Commun 5:4769. Scholar
  6. 6.
    Wasey JAE, Barnes WL (2000) Efficiency of spontaneous emission from planar microcavities. J Mod Opt 47:725–741. Scholar
  7. 7.
    Schmidt TD et al (2011) Evidence for non-isotropic emitter orientation in a red phosphorescent organic light-emitting diode and its implications for determining the emitter’s radiative quantum efficiency. Appl Phys Lett 99:163302. Scholar
  8. 8.
    Kim KH, Moon CK, Lee JH, Kim SY, Kim JJ (2014) Highly efficient organic light-emitting diodes with phosphorescent emitters having high quantum yield and horizontal orientation of transition dipole moments. Adv Mater 26:3844–3847. Scholar
  9. 9.
    Flämmich M et al (2010) Orientation of emissive dipoles in OLEDs: quantitative in situ analysis. Org Electron 11:1039–1046CrossRefGoogle Scholar
  10. 10.
    Penninck L, Steinbacher F, Krause R, Neyts K (2012) Determining emissive dipole orientation in organic light emitting devices by decay time measurement. Org Electron 13:3079–3084CrossRefGoogle Scholar
  11. 11.
    Shin H et al (2014) Blue phosphorescent organic light-emitting diodes using an exciplex forming co-host with the external quantum efficiency of theoretical limit. Adv Mater 26:4730–4734. Scholar
  12. 12.
    Taneda M, Yasuda T, Adachi C (2011) Horizontal orientation of a linear-shaped platinum(II) complex in organic light-emitting diodes with a high light out-coupling efficiency. Appl Phys Express 4:071602. Scholar
  13. 13.
    Mayr C, Taneda M, Adachi C, Brütting W (2014) Different orientation of the transition dipole moments of two similar Pt(II) complexes and their potential for high efficiency organic light-emitting diodes. Org Electron 15:3031–3037. Scholar
  14. 14.
    Komino T, Tanaka H, Adachi C (2014) Selectively controlled orientational order in linear-shaped thermally activated delayed fluorescent dopants. Chem Mater 26:3665–3671. Scholar
  15. 15.
    Komino T, Nomura H, Koyanagi T, Adachi C (2013) Suppression of efficiency roll-off characteristics in thermally activated delayed fluorescence based organic light-emitting diodes using randomly oriented host molecules. Chem Mater 25:3038–3047. Scholar
  16. 16.
    Lamansky S et al (2001) Highly phosphorescent bis-cyclometalated iridium complexes: synthesis, photophysical characterization, and use in organic light emitting diodes. J Am Chem Soc 123:4304–4312CrossRefGoogle Scholar
  17. 17.
    Frischeisen J, Yokoyama D, Adachi C, Brütting W (2010) Determination of molecular dipole orientation in doped fluorescent organic thin films by photoluminescence measurements. Appl Phys Lett 96:29CrossRefGoogle Scholar
  18. 18.
    Moon CK, Kim SY, Lee JH, Kim JJ (2015) Luminescence from oriented emitting dipoles in a birefringent medium. Opt Express 23:A279–A291. Scholar
  19. 19.
    Kim K-H et al (2014) Phosphorescent dye-based supramolecules for high-efficiency organic light-emitting diodes. Nat Commun 5Google Scholar
  20. 20.
    Kim K-H, Ahn ES, Huh J-S, Kim Y-H, Kim J-J (2016) Design of heteroleptic Ir complexes with horizontal emitting dipoles for highly efficient organic light-emitting diodes with an external quantum efficiency of 38%. Chem Mater 28:7505–7510CrossRefGoogle Scholar
  21. 21.
    Jurow MJ et al (2016) Understanding and predicting the orientation of heteroleptic phosphors in organic light-emitting materials. Nat Mater 15:85–91. Scholar
  22. 22.
    Kim K-H et al (2015) Controlling emitting dipole orientation with methyl substituents on main ligand of Iridium complexes for highly efficient phosphorescent organic light-emitting diodes. Adv Opt Mater 3:1191–1196. Scholar
  23. 23.
    Graf A et al (2014) Correlating the transition dipole moment orientation of phosphorescent emitter molecules in OLEDs with basic material properties. J Mater Chem C 2:10298–10304. Scholar
  24. 24.
    Moon C-K, Kim K-H, Lee JW, Kim J-J (2015) Influence of host molecules on emitting dipole orientation of phosphorescent Iridium complexes. Chem Mater 27:2767–2769. Scholar
  25. 25.
    Lampe T et al (2016) Dependence of phosphorescent emitter orientation on deposition technique in doped organic films. Chem Mater 28:712–715. Scholar
  26. 26.
    Materials science suite 2016-2, Schrödinger, LLC, New York, NY (2016).
  27. 27.
    Banks JL et al (2005) Integrated modeling program, applied chemical theory (IMPACT). J Comput Chem 26:1752–1780CrossRefGoogle Scholar
  28. 28.
    Xiang H-F, Xu Z-X, Roy V, Che C-M, Lai P (2007) Method for measurement of the density of thin films of small organic molecules. Rev Sci Instrum 78:034104ADSCrossRefGoogle Scholar
  29. 29.
    Gupta J, Nunes C, Vyas S, Jonnalagadda S (2011) Prediction of solubility parameters and miscibility of pharmaceutical compounds by molecular dynamics simulations. J Phys Chem B 115:2014–2023. Scholar
  30. 30.
    Főrster T (1959) 10th Spiers memorial lecture. Transfer mechanisms of electronic excitation. Discuss Faraday Soc 27:7–17. Scholar
  31. 31.
    Jaguar 9.2, Schrödinger, LLC, New York, NY (2016)Google Scholar
  32. 32.
    Desmond Molecular Dynamics System 4.6, D. E. Shaw Research, New York, NY (2016); Maestro-Desmond Interoperability Tools, Schrödinger, New York, NY (2016)Google Scholar
  33. 33.
    Bowers KJ et al (2006) Scalable algorithms for molecular dynamics simulations on commodity clusters, SC ’06. Proceedings of the 2006 ACM/IEEE Conference on Supercomputing, Tampa, FL, 2006, pp 43.

Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Chang-Ki Moon
    • 1
  1. 1.Department of Materials Science and Engineering, The Graduate SchoolSeoul National UniversitySeoulKorea (Republic of)

Personalised recommendations