The Prepararion Of The Rare Earth Organic Electroluminescent Materials

In this dissertation: 1) neutral ligand 2-Phenyl-imidazo[4, 5-f]1, 10-Phenanthroline (PIP) with high purity was synthesized; 2) 4 ternary complexes of rare earth (Tb³⁺, Eu³⁺, Sm³⁺, Dy³⁺) with benzojc acid (HBA) as the first ligand and PIP as the secondary ligand were prepared; 3) 3 complexs of rare earth Tb³⁺ with benzojc acid, citric acid (H₃Cit), acetylacetone (Hacac) as the first ligand and 1,10-Phenanthroline (phen) as the secondary ligand were prepared; 4) 7 complexes of Tb(III)-acetylaceton-ate doped rare earth Eu³⁺ were prepared. The compositions of complexes were characterized by IR spectra. The results indicate that rare earth ions are coordinated with the ligands. UV spectras show that the ligands and rare earth organic complexes have sharp absorptions in the range of 200～ 400nm that were made mainly by the ligands.Under UV excitation, energy absorbed by the ligands in the complexes can be transmitted to the rare earth ions so that the rare earth ions can emit their characteristic fluorescence. The fluorescence intensity of rare earth Tb³⁺ complexes with (benzojc acid, citric acid, acetylacetone) as the first ligand and 1, 10-Phenanthroline (phen) as the secondary ligand is Tb(acac)3phen>Tb(BA)3phen>Tb(Cit)phen. The fluorescence intensity of Eu(BA)3PIP is obviously higher than the other complexes of rare earth (Tb³⁺, Sm³⁺, Dy³⁺) with benzojc acid as the first ligand and 2-Phenyl-imidazo[4, 5-f]1, 10-Phenanthroline as the secondary ligand. The results indicate that the fluorescence of complexes can be greatly sensitized by appropriate secondary ligand. Among the complexes of Tb(III)-acetylacetone doped rare earth Eu³⁺, the fluorescence emission of Eu³⁺ is greatly sensitized by Tb³⁺ and that of Tb³⁺ were strongly quenched by Eu³⁺.