Theoretical study of electronic structures and optoelectronic properties of blue emitting heteroleptic Iridium(III) complexes containing 1,1-dithiolates

We analyze theoretically the electronic structures and photophysical properties of heteroleptic Iridium(III) complexes (ppy)2Ir(deambt) (1a), (tpy)2Ir(deambt) (2a), (mpb)2Ir(deambt) (3a), (ppy)2Ir(mmbt) (1b), (tpy)2Ir(mmbt) (2b), and (mpb)2Ir(mmbt) (3b) where ppy = phenylpyridine, tpy = 2-(p-tolyl)pyridine, mpb = methyl 4-(pyridine-2-yl)benzoate, deambt = (diethylamino)methanebis (thiolate) and mmbt = methoxymethanebis (thiolate) respectively using the density functional theory (DFT). We also investigated the influence of ancillary and cyclometalated ligands on the photophysical properties of the above complexes. The calculated optical transition energies are in good agreement with the experimental values. The low lying transitions are categorized as metal to ligand charge transfer (MLCT) and ligand to ligand charge transfer (LLCT) transitions.