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Density functional theory analysis of a mixed‐ligand iridium compound for multi‐color organic light‐emitting diodes
Author(s) -
Polosan Silviu,
Chow Tahsin J.,
Tsuboi Taiju
Publication year - 2008
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.1329
Subject(s) - chemistry , density functional theory , iridium , time dependent density functional theory , phosphorescence , transition dipole moment , absorption spectroscopy , absorption (acoustics) , homo/lumo , oled , dipole , computational chemistry , molecule , organic chemistry , optics , physics , layer (electronics) , fluorescence , catalysis
Electronic states and their energies are calculated for a mixed‐ligand Ir(III) compound, (5‐chloro‐8‐hydroxyquinoline) bis(2‐phenylpyridyl) iridium (called IrQ(ppy) 2 ‐5Cl) using time‐dependent density functional theory (TDDFT) calculations and are compared with the experimental result. A good agreement is obtained between the calculated and measured absorption spectra. The d‐π Q * molecular orbital transition gives the lowest‐energy triplet state absorption band. Its energy is estimated as 1.84 eV (671 nm), which is close to the absorption band position of 1.86 eV (666 nm) observed for IrQ(ppy) 2 ‐5Cl doped in 4,4′‐ N , N ′‐dicarbazole‐biphenyl (CBP) host and of 1.88 eV (660 nm) observed for IrQ(ppy) 2 ‐5Cl doped in polystyrene (PS). The second triplet state absorption band is caused by d‐π ppy transition. Its position is calculated as 2.51 eV (494 nm). The dipole moment is estimated as 3.45 D, which is lower than the dipole moment of fac ‐Ir(ppy) 3 . This is understood by a reduced charge transfer between Ir(III) and quinoline ligand. Copyright © 2008 John Wiley & Sons, Ltd.