Synthesis and fluorescence properties of Eu3+ -trimellitic acid-1,10-phenanthroline ternary complexes doped with la3+ ion

The rare-earth complexes with aromatic carboxylic acids are a kind of good luminous materials because of the good light-emitting singleness, high luminous intensity and a high quantum efficiency. In recent years, more and more attention has been paid to the fluorescence properties of these complexes. The research showed that addition of the non-fluorescent rare-earth ions can enhance the fluorescence intensity of rare-earth complexes. The trimellitic acid, which has a variety of forms of coordination, is a good performance of the organic ligand. A lot of researches about the complexes of europium with trimellitic acid has been reported, however the study of europium-lanthanum complexes with trimellitic acid and 1,10-phenanthroline has been seldom reported. In this study, the series of solid complexes Eu1-x Lax ( TLA )phen(x=0,0. 1,0. 2,0. 3,0.4, 0.5, 0.6, 0.7, 0.8 ) were obtained by the trimellitic acid, 1,10-phennanthroline and mixed rare earth chloride of EuCl3 and LaCl3 in CH3CH2OH solution. These complexes were characterized by IR spectrum, TG-DTG and SEM. The IR spectrum showed that the oxygen atoms of carboxylate and the nitrogen atoms of phen coordinate with RE3+, and these complexes have similar structure. The TG-DTG analysis showed that these complexes are thermally stable. The fluorescence properties of these complexes were also studied. The results indicated that the complexes can emit intense characteristic fluorescence from europium ion. The fluorescence intensities of europium ions are sensitized by the doping of lanthanum ions and the intensity of fluorescence is the best when Ti(Eu3+ ): Ti(La3+ ) =0.5:0.5, at same time the position of the emission peak does not changed.