Iridium(III) complexes with 1-phenylisoquinoline-4-carbonitrile units for efficient NIR organic light-emitting diodes

Hongyang Zhang, Yuqing Xu, Zhao Chen, Shuming Chen, Rong Liu (Corresponding Author), Wai Yeung Wong (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Achieving the high external quantum efficiency (EQE) of near-infrared (NIR) emission in iridium(III) complexes still remains a challenge owing to their unsteady excited states which easily decay to the ground states through the nonradiative pathways. Herein, three Ir(III) phosphors in which the cyclometalated ligand 1-phenylisoquinoline-4-carbonitrile (piq-CN) is functionalized with the cyano, tert-butyl, and dimethyl groups are developed (CN-CNIr, Bu-CNIr, and DM-CNIr, respectively). Three simple synthetic steps can afford this class of deep red to NIR Ir(III) emitters. The organic light-emitting diodes (OLEDs) based on Bu-CNIr and DM-CNIr attain the maximum EQEs of 7.1% and 7.2% with the emission peaks at 695 and 714 nm, respectively. This strategy using substituted piq-CN derivatives as the cyclometalated ligands can offer an effective approach to promote the radiative rate of NIR-emitting Ir(III) materials. An insight into how the electron-withdrawing and electron-donating substituents on ligands influence the optoelectronic properties of their Ir(III) complexes is also provided.

Original languageEnglish
Article number102911
JournaliScience
Volume24
Issue number8
DOIs
Publication statusPublished - 20 Aug 2021

Keywords

  • Optical materials
  • Optoelectronics
  • Photonics

ASJC Scopus subject areas

  • General

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