Premium
Organic light‐emitting materials based on iridium(III) complexes bearing phenanthroimidazole ligands
Author(s) -
Jayabharathi Jayaraman,
Sathishkumar Ramalingam,
Thanikachalam Venugopal
Publication year - 2014
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3292
Subject(s) - phosphorescence , iridium , chemistry , electroluminescence , photochemistry , oled , excited state , photoluminescence , ligand (biochemistry) , microsecond , imidazole , fluorescence , optoelectronics , stereochemistry , materials science , catalysis , organic chemistry , atomic physics , biochemistry , physics , receptor , layer (electronics) , quantum mechanics , astronomy
We present the elegant synthesis and the photophysical and electroluminescent properties of a series of cyclometalated iridium(III) complexes [Ir(PPI) 2 (pic), PPI: 1,2‐diphenyl‐1H‐phenanthro[9,10‐d]imidazole; pic: picolinic acid]. The Ir(PPI) 2 (pic) complexes showed characteristic phosphorescence with an emission range of 556–579 nm and a high quantum efficiency with microsecond lifetimes. The strongly allowed phosphorescence in these complexes is the result of significant spin–orbit coupling of the Ir center. All bis(PPI) derivatives exhibit intense triplet metal‐to‐ligand charge transfer (MLCT) photoluminescence in the fluid solutions at room temperature. The impact of different solvents, substituents on the phenanthroimidazole ligands and complex concentrations upon their emissive behavior have been examined and demonstrate that their emission energies can be systematically modified. Weak bands located at longer wavelength have been assigned to the 1 MLCT ← S 0 and 3 MLCT ← S 0 transitions of iridium complexes. Application of the 3 MLCT excited state of the [Ir(PPI) 2 (pic)] materials in organic light‐emitting devices are described. Copyright © 2014 John Wiley & Sons, Ltd.