Preparation And Fluorescence Properties Of Doped And Coated Trimelltic Acid Europium

Rare earth organic complex is an important class of fluorescent light-emitting material. The research show that addition of a centain amount of non-fluorescent rare earth ions or coating around the europium complexes significantly enhance the fluorescence intensity and reduce the processing costs.In this paper, binary complex of Eu(TLA) and ternary complex of Eu(TLA)phen were prepared by chemical coprecipitation and studied from the three aspects of the reaction temperature, pH values and solution concentration in preparation. The complexes which doped by non-fluorescent ions of Gd, La, Y were prepared based on the synthesis of the ternary complex. And the Eu(TLA)/SiO2 was prepared by sol-gel method. The fluorescence properties and structure of the prepared products were analyzed by fourier transform infrared, thermogravimetric analyzer, fluorospectrophotometer and scanning electron microscope.The results showed that the complexes of Eu(TLA) and Eu(TLA)phen were preparad at the reaction temperature of 80℃, pH value of 7, solution concentration of 0.1 mol/L, which is the best preparation conditions. Infrared spectra showed that Eu(TLA) and Eu(TLA)phen complexes were prepared by the coordination of chelating bidentate. The fluorescence spectroscopy showed that the Eu(TLA)phen, which has a similar characteristic peak shape and position of Eu(TLA), had a increasing relative fluorescence intensity that expressed as the cooperative effect of the second ligand. The results showed that non-fluorescence ion had relative good fluorescence enhancement effect to complexs. The optimum doping mole fraction was X_Gd =0.6, X_La =0.5, X_Y =0.2 and the fluorescence enhancement order of non-fluorescent ions was Gd³⁺> La³⁺> Y³⁺. Infrared spectra showed that Eu(TLA)/SiO₂ composite was obtained. The coating process was studied from the pH values, TEOS dosage, the second amount of deionized water and water bath temperature. The best preparation conditions were pH = 9, TEOS amount of 2mL, water bath temperature of 50℃, the second amount of deionized water 6mL. Compared with uncoated complex, the fluorescence intensity of SiO₂ coated material increased by about 48%.