Theoretical investigation on the electronic structures and photophysical properties of a series of iridium(III) complexes based on amidate ancillary ligand

The electronic and photophysical properties of a series of iridium(III) complexes based on amidate ancillary ligand have been investigated using the density functional theory (DFT) and time-dependent density functional theory (TDDFT). Ionization potential (IP), electron affinities (EA) and reorganization energy (λ_{hole/electron}) have also been obtained to evaluate the charge transfer and balance properties between hole and electron. The absorption and emission properties can be altered by the different electron-withdrawing and electron-donating substituents in the N-acetylaniline. The calculated lowest energy emissions for 1-6 are localized at 542, 538, 535, 557, 538, and 495 nm, respectively. It can also be seen that the complex 4 and 6 have possibly the largest and smallest k_r values than among these complexes. It is anticipated that the theoretical work can be useful for designing promising phosphorescent materials for use in the organic light-emitting diodes.