A dinuclear Eu(III) complex [HN(CH₃CH₂)₃]₂[Eu₂(bdb)₄]•CH₃CH₂OH [H₂bdb＝4,4'-bis (4",4",4"-trifluoro-1",3"-dioxobutyl)-o-terphenyl] was synthesized. The complex emits bright red luminescence, characteristic of the ⁵D₀ → ⁷F_J (J＝0～4) emission peaks of Eu^3＋ under near UV irradiation. The luminescence lifetime of the emitting ⁵D₀ level of the complex is 704 μs. The decay curve can be fit with a single exponential model. Monitored at 614 nm, excitation wavelength is located in the range of 250～420 nm. Excitation intensity of the complex is strong enough at 395 nm and the complex can be well excited by the 395 nm emission light of InGaN chip. The investigation of the temperature dependence of PL intensity for the Eu(III) complex shows that the complex can keep up with good emission intensity as the temperature rises to 200 ℃. The thermogravimetric analyses curve for complex shows the complex is up to 260 ℃. The luminescence properties and thermostability meet the requirements of fabrication of LED device. Bright red conversion light-emitting diode (LED) device was fabricated by coating complex onto 395 nm InGaN chip. When the mass ratio of the europium complex to the silicone is 1∶20, the LED CIE chromaticity coordinates is x＝0.61, y＝0.31. The luminescence efficiency of device is 3.64 lm/W under 20 mA forward bias. White conversion LED was fabricated by coating this europium complex and bis(2-(2'-hydroxyphenyl)benzothiazolate)zinc [Zn(btz)₂] onto 395 nm InGaN chip. The appropriate mass ratio to obtain white light of the europium complex, [Zn(btz)₂] and the silicone is 1∶1∶25, the LED CIE(Commission International d'Eclairage) chromaticity coordinates is x＝0.32, y＝0.32, T_c＝6026 K, R_a＝81 under 20 mA forward bias. The luminescence efficiency of device is 1.26 lm/W. The results indicate that the europium complex can act as red component in the fabrication of white LEDs.

Key words: europium complex, chemical synthesis, phosphor, luminescence, LED