Systematic Control of the Orientation of Organic Phosphorescent Pt Complexes in Thin Films for Increased Optical Outcoupling

Jongchan Kim, Thilini Batagoda, Jaesang Lee, Daniel Sylvinson, Kan Ding, Patrick J.G. Saris, Ushasree Kaipa, Iain W.H. Oswald, Mohammad A. Omary, Mark E. Thompson, Stephen R. Forrest

Research output: Contribution to journalArticlepeer-review


Orienting light-emitting molecules relative to the substrate is an effective method to enhance the optical outcoupling of organic light-emitting devices. Platinum(II) phosphorescent complexes enable facile control of the molecular alignment due to their planar structures. Here, the orientation of Pt(II) complexes during the growth of emissive layers is controlled by two different methods: modifying the molecular structure and using structural templating. Molecules whose structures are modified by adjusting the diketonate ligand of the Pt complex, dibenzo-(f,h)quinoxaline Pt dipivaloylmethane, (dbx)Pt(dpm), show an ≈20% increased fraction of horizontally aligned transition dipole moments compared to (dbx)Pt(dpm) doped into a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl, CBP, host. Alternatively, a template composed of highly ordered 3,4,9,10-perylenetetracarboxylic dianhydride monolayers is predeposited to drive the alignment of a subsequently deposited emissive layer comprising (2,3,7,8,12,13,17,18-octaethyl)-21H,23H-porphyrinplatinum(II) doped into triindolotriazine. This results in a 60% increase in horizontally aligned transition dipole moments compared to the film deposited in the absence of the template. The findings provide a systematic route for controlling molecular alignment during layer growth, and ultimately to increase the optical outcoupling in organic light-emitting diodes.

Original languageEnglish
Article number1900921
JournalAdvanced Materials
Issue number32
Publication statusPublished - 2019

Bibliographical note

Funding Information:
This work was supported by the Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy, under Award Number DE-EE0007626, and Universal Display Corporation. The authors thank Dr. Zhongrui Li and Dr. Kai Sun for the helpful comments and suggestions. The authors thank Dr. Jeff Kampf and Dr. Ralf Haiges for help with the crystallographic studies of Tint, PtD, and (dpm)Pt(dbx). M.A.O. gratefully acknowledges support by the Welch Foundation (Grant No. B-1542) and the U.S. National Science Foundation (Grant No. CHE-1413641).

Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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