Efficient red organic light-emitting diodes based on a dinuclear europium complex

Pure red organic light-emitting diodes based on a dinuclear europium complex with a structure of (TTA)3Eu(PYO)2Eu(TTA)3 (TTA = thenoyltrifluoroacetonate, PYO = pyridine N-oxide) were presented. The devices showed pure red emission at a peak wavelength of 612 nm with a full width at half maximum of 3 nm, which is a characteristic emission from Eu3+ ion based on 5D0 → 7F2 transition. The maximum brightness and electroluminescent (EL) efficiency reached 340 cd/m2 at a driving voltage of 19 V and 2.4 cd/A (0.78 lm/W) at a current density of 0.14 mA/cm2, respectively.