High Performance NIR OLEDs with Low Efficiency Roll-Off by Leveraging Os(II) Phosphors and Exciplex Co-Host

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Original languageEnglish
Article number2102787
Journal / PublicationAdvanced Functional Materials
Issue number33
Online published13 Jun 2021
Publication statusPublished - 16 Aug 2021


Near-infrared (NIR) organic-light emitting devices (OLEDs) with high radiance are useful for applications including invisible marking, communication, and biomedical imaging. However, performances of NIR OLEDs are typically limited by their severe efficiency roll-offs at high current density. Herein, three isoquinolinyl azolate based Os(II) complexes (Isq-1–3) with short radiative decay lifetime (in hundreds of ns), and photoluminescence with peak wavelengths > 745 nm and quantum yield up to 48% as doped thin films, are reported. Upon concomitant employment of exciplex-forming co-host (tris(4-carbazoyl-9-ylphenyl)amine and 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine), efficiency roll-off is greatly reduced, giving external quantum efficiency of 9.66% at a current density of 300 mA cm−2. A maximum radiance over 170 W sr−1 m−2 is also achieved in devices based on Isq-2 and Isq-3.

Research Area(s)

  • efficiency roll-off, exciplex, near-infrared, organic light-emitting diodes, osmium(II) complexes

Citation Format(s)