The effect of substituted pyridine ring in the ancillary group on the electronic structures and phosphorescent properties for Ir(III) complexes from a theoretical viewpoint

Abstract

The electronic structures and photophysical properties of eight phosphorescent Ir(III) complexes containing (4′-substituted-2′-pyridyl)-1,2,4-triazole ancillary ligands have been theoretically studied via density functional theory and time-dependent density functional theory calculations. The effect from the electron-donating and electron-accepting substituents on charge injection, transport, absorption, and phosphorescent properties of all the studied complexes has been investigated. The calculated results reveal that the different substituted ligands can modify the absorption and emission properties. In addition, ionization potential (IP), electron affinities (EA) and reorganization energy were obtained to evaluate the charge transfer and balance properties between hole and electron. The calculated results show that the different substitute groups affect the charge transfer rate and balance. The theoretical work can provide a description of photophysical properties through substitution, which would be useful to guide new design and synthesis of phosphorescent materials.