Synthesis and characteristics of a europium complex using pyridyl oxadiazole derivative as a secondary ligand

A novel europium complex using 2-(4-methoxy)phenyl-5-(2-pyridyl)-1,3,4-oxadiazole as a secondary ligand was synthesized and characterized. Its thermal stability and UV absorption and photoluminescence of this europium complex, as well as its electroluminescence in polymer light-emitting devices (PLEDs) were investigated. The results show that this europium complex displayed intense UV absorption band around 350 nm and sharp red emission peaked at 612 nm with a full width at half maximum of 9 nm in chloroform. The PLEDs with this europium complex doped into a blend of poly(N-vinylcarbazole) and 5-biphenyl-2-(4-tert-butylphenyl)-1,3,4-oxadiazole exhibited a light intensity of 12 cd/m2 at 24 V with a characteristic red emission of europium ion at 613 nm. This implies that the europium complex using the pyridyl 1,3,4-oxadiazole derivative as a secondary ligand can exhibit intense sharp emission of europium ion under opto-excitation and electric-excitation.