Abstract: An organic compound with both electron-transporting and hole-transporting groups,1-ethyl-2-(2-[(4-N,N'-diphenyl)-phenylamine]-5-phenyl-1,3,5-oxadiazole) imidazo[4,5]-1,10-phenanthroline(EtPOTIP),was designed and synthesized.With EtPOTIP as the secondary ligand and dibenzoylmethane(HDBM) as the first ligand,the corresponding europium(Ⅲ) ternary complex,Eu(DBM)₃EtPOTIP, was prepared.EtPOTIP and the complex were characterized by elemental analysis, ¹H NMR,IR and mass spectroscopy.TG and DSC analyses show that the complex exhibits high thermal stability and high T_g temperature.UV-Vis absorption and photoluminescence measurements demonstrate that the excitation light energy absorbed by the organic ligands was transferred to the central Eu³⁺ ion efficiently in the ternary complex,and the latter is an excellent red emitting material with a high quantum yield of 0.48.A bright tri-layer organic light-emitting diode(OLED) with structure of ITO/CuPC(15 nm)/TPD(45 nm)/Eu(DBM)₃EtPOTIP(20 nm)/Alq₃(40 nm)/Ca(30 nm)/Al(100 nm) was fabricated,and the electroluminescence measurements indicate that EtPOTIP exhibits both electron-transporting and hole-transporting properties and the latter is dominant.Existence of EtPOTIP in the complex obviously improves the performance of the device.

Key words: Europium(Ⅲ), Ternary complex, Electron-transporting, Hole-transporting, Organic light-emitting diodes(OLEDs)