With two azatriphenylene-type ligands, two novel ternary europium(Ⅲ) complexes Eu(DBM) ₃L₁ and Eu(DBM)₃L₂ (DBM=dibenzoylmethanato; L₁,L₂=azatriphenylene-type ligands) have been synthesized and characterized by elemental analysis, IR and UV-Vis spectra. Photo-luminescent studies show that the synergistic complexation of the second ligand has indeed led to the construction of efficiently emitting europium(Ⅲ) complexes, and as a result both complexes exhibit intense emission typical of Eu³⁺ ion. Using TPD as hole transporting material and Gd(DBM)₃bath (bath=bathophenanthroline) as electron transporting material, three layer devices with the emitting layer formed by codeposition of luminescent complex and TPD were fabricated: ITO/TPD(30 nm)/ Eu(DBM)₃L₁(L₂):TPD(1:2)(50 nm)/Gd(DBM)₃bath(30 nm)/Mg:Ag. Based on the EL measurement results, it can be concluded that those ternary europium complexes possess excellent electron-transporting abilities, and the azatriphenylene-type second ligands play an important role in improving the electron-transporting abilities of the complexes. OEL devices with Eu(DBM)₃L₁ and Eu(DBM)₃L₂ as emitting materials have low onset driving voltage of 3 V, and the maximum pure red Eu(Ⅲ)-based luminance of 148 cd·m^-2 and 110 cd·m^-2 were observed at 12 V, 52 mA·cm^-2 and 13 V, 42 mA·cm^-2 respectively.

Key words: europium complex, azatriphenylene, photoluminescence, electroluminescence