Highly Efficient Red Phosphorescent OLEDs Based on Ir(III) Complexes with Fluorine-substituted Benzoylphenylpyridine Ligand

Abstract

Four orange-red phosphorescent Ir(III) complexes were designed and synthesized based on the benzoylphenylpyridine ligand with a fluorine substituent. Multilayered OLEDs with the device structure, ITO/2-TNATA/NPB/CBP : 8% Ir(III) complexes/BCP/Liq/Al, were fabricated using these complexes as dopant materials. All the devices exhibited orange-red electroluminescence and their electroluminescent properties were quite sensitive to the structural features of the dopants in the emitting layers. Among these, the maximum luminance (14700 cd/m 2 at 14.0 V) was observed in the device containing Ir(III) complex 1 as the dopant. In addition, its luminous, power and quantum efficiency were 11.7 cd/A, 3.88 lm/W and 9.58% at 20 mA/cm 2 , respectively. The peak wavelength of electroluminescence was 606 nm with CIE coordinates of (0.61, 0.38) at 12.0 V. The device also showed stable color chromaticity with various voltages.

Structural Mimics of Phenyl Pyridine (ppy) – Substituted, Phosphorescent Cyclometalated Homo and Heteroleptic Iridium(III) Complexes for Organic Light Emitting Diodes – An Overview

“…H. J. Kang et al ., synthesised and characterised a series of red phosphorescent heteroleptic Ir(III) complexes (127–130, Figure ) with fluorine substituted benzoyl phenylpyridine ligand . The absorption spectra of Ir(III) complexes 127–130 below 360 nm were assigned to the spin‐allowed 1 π‐π* transition involving Bzppy (benzoylphenyl pyridine) ligands, and the band at approximately 400 nm to a spin‐allowed metal charge transfer ( 1 MLCT) band.…”

Metallo‐organic Conjugated Systems for Organic Electronics

“…Kang et al. reported the benzoylphenylpyridine‐based orange‐red Ir(III) complexes ( 72 – 75 ) and explored their phosphorescent properties for OLEDs 77. Complex 72 showed the maximum luminance of 14700 cd m −2 at 14.0 V and current, power and quantum efficiencies were found to be 11.7 cd A −1 , 3.88 lm W −1 and 9.58 % at 20 mA cm −2 , respectively.…”

A Comparative Study of Ir(dmpq)2(acac) Doped CBP, mCP, TAPC and TCTA for Phosphorescent OLEDs

“…The most promising strategy to fabricate PhOLEDs is based on the transition metal complex luminescent materials. Among the transition metal complexes, Ir (III) complexes are considered the most promising emitters in PhOLEDs based on their relatively high phosphorescence quantum yields, short triplet excited state lifetimes, excellent color tunability from blue to deep red, and splendid thermal and electrochemical stability [7][8][9][10][11].…”