Preparation And Fluorescence Properties Of Rare Earth Doped Europium Organic Complexes

The rare earth element has a unique electronic structure,and the forbital electron is shielded by the inner layer electron.The transition of f-f is basically not affected by the external environment,and the emission spectrum shows a sharp line spectrum with high luminous intensity and good color purity.The europium ion and terbium ion represent red fluorescence and green fluorescence,respectively.The emission band produced by the ion transition is very narrow,close to the atomic spectrum,and the peak shape is sharp,indicating that both the europium ion and the terbium ion are ideal luminescent ions.The complex synthesized by europium ion and terbium ion has high luminescence intensity and high fluorescene purity.In recent years,researchers have focused on the study of rare earth complexes in pure ternary complexes of europium and terbium.Fluorescence properties are altered by the regulation of organic ligand structures,but because of the high price of rare earth elements europium and terbium,expensive production costs limit the widespread use of such luminescent materials.Therefore,it is our new goal to explore phosphors with low production costs and good fluorescence performance.The luminescence intensity,fluorescence lifetime,color purity and thermal stability of the rare earth europium complexes are mainly related to the first ligand structure,doped ions and doped amount.In this thesis,the effects of different doped ions,doped amount and matching the energy level of the first ligand to the illuminating center ion on the fluorescence properties of the complexes.The mainly contents are as follow:?1?Aseriesofequimolarratiodopedternarycomplex Eu_0.5RE_0.5?TTA?₃Phen?RE=Gd,Tb,Y?was synthesized by low temperature liquid phase method.Elemental analysis,infrared spectroscopy and Ultraviolet spectrum were studied.The spectrum shows that the doped complex is similar to the pure ternary complex Eu?TTA?₃Phen and does not generate new chemical bonds.Comparingthefluorescencepropertiesofthedopedcomplex Eu_0.5RE_0.5?TTA?₃Phen?RE=Gd,Tb,Y?andthepureternarycomplex Eu?TTA?₃Phen,it is found that the equimolar ratio of doped Gd³⁺and Y³⁺can increase the luminescence intensity of the complex Eu?TTA?₃Phen,and the fluorescence lifetime is also extended.Considering the fluorescence performance and production cost of the two complexes,Y³⁺is used as the best doped ion for the complex Eu?TTA?₃Phen,finally.?2?The ternary complexes with different molar ratios of Y³⁺doped were synthesized.By characterizing the fluorescence properties of the doped complex Eu_xY_1-x?TTA?₃Phen?x=0.4,0.5,0.6?emission and excitation spectra,fluorescence lifetime,thermal stability,etc.The results show that as the doped amount of Y³⁺increases,the luminescence intensity of the sample increases,and the fluorescence lifetime,thermal stability and color purity hardly change.When the doped amount is Eu³⁺:Y³⁺=1:1,the complex Eu_0.5Y_0.5?TTA?₃Phen has the best luminescence intensity,which is characterized by the characteristic luminescence of Eu³⁺.As the doped amount of Y³⁺continues to increase,the fluorescence intensity of the complex gradually decreases.?3?The organic ligand 1,5-distyrylacetylacetone?Dsacac?was synthesized based on the hydroxyl aldehyde condensation reaction mechanism.Using Dsacac as the first ligand,the pure ternary complex Eu?Dsacac?₃Phen and Eu/Y doped complexes of different molar ratios Eu_xY_1-x?Dsacac?₃Phen?0.4,0.5,0.6?were synthesized.The structure,stability,fluorescence properties of Eu?Dsacac?₃Phen and Eu_xY_1-x?Dsacac?₃Phen and the energy transfer process of the complexes were analyzed.The results show that the appropriate amount of non-fluorescent ion Y³⁺can increase the luminescence intensity of the complex Eu?Dsacac?₃Phen.?4?Thefluorescencepropertiesofthedopedcomplexes Eu_0.5Y_0.5?TTA?₃Phen and Eu_0.5Y_0.5?Dsacac?₃Phen were compared.It was found that the luminescence intensity and color purity of the complex Eu_0.5Y_0.5?TTA?₃Phenweresignificantlybetterthanthecomplex Eu_0.5Y_0.5?Dsacac?₃Phen.Further discussion on the energy transfer mode of the first ligand and rare earth ions.The above results showed that Eu_0.5Y_0.5?TTA?₃Phen was more suitable for the industrial production of phosphors.