Efficient solution-processed yellow/orange phosphorescent OLEDs based on heteroleptic Ir(Ⅲ) complexes with 2-(9,9-diethylfluorene-2-yl)pyridine main ligand and various ancillary ligands

Xuejing Liu, Bing Yao, Hailong Wang, Baohua Zhang*, Xingdong Lin, Xiaofei Zhao, Yanxiang Cheng, Zhiyuan Xie, Wai Yeung WONG

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Efficient solution-processible yellow/orange emissive phosphors are highly required in solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs). With respect to phenyl pyridine (ppy)-type Ir(III) complexes, 2-(9,9-diethylfluoren-2-yl)pyridine (Flpy)-type Ir(III) complexes have huge potential in yellow/orange s-PhOLEDs due to their extended conjugation and excellent solubility in common organic solvents. Herein, a new series of phosphorescent Ir(III) complexes, i.e. Ir(Flpy)2pic-N–O, Ir(Flpy-CF3)2pic-N–O, Ir(Flpy-CF3)2dbm and Ir(Flpy-CF3)2acac, based on Flpy main ligand and picolinic N-oxide (pic-N–O), acetylacetone (acac), and dibenzoyl methane (dbm) ancillary ligands are synthesized. The photophysical, electrochemical, and electroluminescent (EL) properties of these phosphorescent Ir(III) complexes are investigated in details. By introducing the CF3 group in Flpy ligand and varying the ancillary ligands, the emission spectra of these phosphorescent complexes are tuned in a large range with EL emission peaks from 544 nm to 588 nm. The s-PhOLEDs employing these phosphors show promising EL performance with maximum external quantum efficiency (EQE) from 15.4% to 23.7% and high power efficiency from 61.9 l m W−1 to 80.4 l m W−1. These highly efficient phosphorescent Ir(III) complexes may serve as ideal chromaticity components in solution-processed full-color displays and lighting devices.

Original languageEnglish
Pages (from-to)197-203
Number of pages7
JournalOrganic Electronics
Volume54
DOIs
Publication statusPublished - Mar 2018

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

User-Defined Keywords

  • Ancillary ligands
  • Iridium complex
  • Organic light-emitting diode
  • Solution-processed
  • Yellow/orange emission

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