New red electrophosphor based on Ir(III) complex of 2,3,4-triphenylquinoline

Abstract

Abstract 2,3,4-Triphenylquinoline (tpq) ligand and its Ir(III) complex Ir(tpq) 2 (acac) were prepared and their photonic properties were investigated as red electrophosphorescent material. The photoluminescence (PL) spectra of tpq and Ir(tpq) 2 (acac) in dichloromethane showed a peak at 450 nm and 607 nm, respectively, at room temperature. The small Stokes shift between the 3 MLCT absorption and emission bands shows that Ir(tpq) 2 (acac) emits from a predominantly 3 MLCT excited state. The theoretical calculation of the Ir(III) complex was performed by an ab initio method, and the result calculated by time dependent density functional theory (TD-DFT) showed that the Ir(III) complex underwent a strong 3 MLCT transition because of the strong coupling between the 5d-orbital of Ir atom and the highest occupied molecular orbital (HOMO) of tpq ligand. Thus, it is concluded that this complex is a good candidate for a highly efficient electrophosphorescent material.