Series Of New Europium Complexes, Photoluminescence And Film Forming Properties

In order to obtain the lanthanide complexes with excellent photo-luminescence and the Langmuir-Blodgett film-forming properties, A series of 1,10-phenanthroline derivatives(N_n, n=6, 7, 8, 10, 12, 14, 16, 18.) with long paraffin chains have been synthesized:Anew compound 2-m-pyridylmethanamido-5-phenyl-[1,3,4]-oxadiazole has also been synthesized as the first ligand(L):With the compounds N_n as the secondary ligands and L as the first ligand, eight novel ternary europium(III) complexes were synthesized. UV-vis absorption spectra, fluorescent spectra, photoluminescent spectra, quantum yield, the Langmuir-Blodgett film-forming properties and fluorescent spectra of spin-coated films of the complexes were studied.In the excitation spectra of the complexes, the absorption bands exhibit apparent red shift with the increase of the concentrations of the complexes in THF solution, strong absorption in the region of 300-475nm were observed in the excitation spectra of the solid state complexes. This phenomena could be attributed to the formation of associated complexes between the neighbor second ligands when the complexes were in solid state or concentrated solutions. Absorption of the emitting complex in near UV-vis region can improve carrier injection and balance in OLED devices, which is very important as an excellent electroluminescent materials,The solid state complexes exihibit intense red emission typical of Eu ion at room temperature, the lifetimes of ⁵D₀ state are about 2ms, which illustrated that concentration quenching of this series of complexes is no apparent in the solid state. This kind of complexes may be excellent red emitting electroluminescent materials because of their high quantum yield and high color purity.The LB films of this series of complexes were successfully prepared. Theπ-A isotherm show that the Langmuir-Blodgett film-forming property of them is excellent. Monochromaticity of spin-coated films is better than that of solid state complexes, which illustrates that these complexes are excellent thin film electroluminescence materials.