Synthesis and Luminescence of Eu(III) Complexes Based on 4,4′- Bis(4",4",4"-trifluoro-1",3"-dioxobutyl) -biphenyl

Two complexes Eu-2 ( btb)(3) ( H2O)(4) ( 1 ) and Eu-2 ( btb )(3) ( phen )(2) ( 2 ) [ H(2)btb = 4, 4'-bis (4 '', 4 '', 4 ''-trifluoro-1 '', 3 ''-dioxobutyl) -biphenyl, phen = 1, 10-phenanthroline] were synthesized. Their structures were characterized by elemental analysis, IR, UV and FAB-Ms. Both two complexes emit red luminescence, characteristic of the D-5(0) -> F-7(j) (J = 0-4) emission bands of Eu3+ under near UV irradiation. Monitored at 614 nm, the strongest excitation wavelength located at 395 nm, which matched to the emission light of InGaN chip. Two red conversion light-emitting diodes( LEDs) devices were fabricated by coating complex onto InGaN-based LED chip that emits 395 nm light. When the mass ratio of the red phosphor to the silicone was 1: 25, the two LEDs CIE chromaticity coordinates( complex 1: x(1) =0.5210, y(1) = 0.2285; complex 2: x(2) = 0.5835, y(2) = 0.2857) are close to the National Television Standard Committee( NTSC) standard values for red color, the luminescence efficiency of devices are 0.65 lm/W for complex 1, 0.76 lm/W for complex 2. The results indicate that complexes Eu-2 ( btb)(3) ( H2O)(4) and Eu-2 ( btb)(3) ( phen) (2) can act as red components in the fabrication of white LED.