Abstract: Theoretical studies of electronic structures and photochemical properties were performed via DFT/B3LYP method on three Ir(Ⅲ) complexes, each of which contains two quinoline derivatives and a single acetylacetonate. Our calculation results indicate that the substitution of biphenyl and naphthalene instead of benzene can decrease PI and increase EA values, especially for complex 3, which can be used as the electron-transport materials and hole-transport materials. At the same time, this substitution can decrease the energy gap between HOMO and LUMO which leads to the red-shift of absorption spectra. The T1 state transitions are mainly HOMO→LUMO, and the process of phosphorescence emission of T1→S0 is the mixture of MLCT and LLCT.

Key words: Iridium complex, Ground state configuration, Molecular orbital, Electronic spectrum