Theoretical study on the influence of ancillary ligand on the energy and optical properties of heteroleptic phosphorescent Ir(III) complexes

► The geometries, energies, and electronic properties of a series of phosphorescent Ir(III) complexes including FIrpic, FIrmpic, FIrpca, and FIrprza have been characterized with DFT calculations. ► The predictions revealed that the nature of the ancillary ligands can influence the distributions of frontier molecular orbitals and their energies, resulting in impact on the transition character and change in the emission color. ► Our result also indicates that the substitute groups and different auxiliary ligand not only change the character of transition but also affect the rate and balance of charge transfer.