Preparation And Properties Study Of Europium Doped Perovskite-Type Titanate Luminescent Materials

The rare earth ion Eu³⁺has a simple energy structure,long fluorescence lifetime,high color purity,become the main activator of red luminescent materials.The luminescence properties of Eu³⁺are closely related to the matrix environment in which it is located.Titanate materials are an ideal matrix material because of their good chemical stability and easy doping of crystal forms.This article used Eu³⁺as an activator,Eu³⁺doped perovskite titanate red luminescent materials were prepared by sol-gel method.Their structures and compositions were characterized by DTA-TGA,XRD,IR and systematically studied its luminescence properties through excitation and emission spectra.A series of perovskite Ba_xSr_1-xTi O₃:Eu³⁺?x=0,0.256,0.5,0.6,0.77,1?phosphors were prepared by sol-gel method.Through excitation and emission spectra analysised a series of phosphors,it was found that when Ba:Sr was0.77:0.23,the phosphor Ba_0.77Sr_0.23TiO₃:Eu³⁺had the best luminous properties.So Ba_0.77Sr_0.23TiO₃ as the matrix,Ba_0.77Sr_0.23TiO₃:Eu³⁺phosphors had been detailedly studied.The results showed that when the annealing temperature was between 600?and 800?,the pH of the reaction environment was between 1 and 11,which was the tetragonal Ba_0.77Sr_0.23TiO₃.The phosphor could be effectively excited by the visible light of 466nm to emit red light.The experimental conditions were further optimized to determine the annealing temperature of Ba_0.77Sr_0.23TiO₃:Eu³⁺was 700°C,pH was 1,Eu³⁺doping amount of 7%,at this time Ba_0.77Sr_0.23TiO₃:Eu³⁺phosphor emited strong red light.A series of cubic phase perovskite Sr_1-xLa_xTiO₃:Eu³⁺?x=0,0.1,0.2,0.3,0.4,1?phosphors were prepared by sol-gel method.The luminescent properties of the series of phosphors were analyzed.It was found that when La:Sr was 4:0.6,the phosphor Sr_0.6La_0.4TiO₃:Eu³⁺had the best luminous properties,so Eu³⁺doped Sr_0.6La_0.4TiO₃ phosphors had been detailedly studied.It was found that when the annealing temperature was 700?and 750?,the sample was pure cubic phase Sr_0.6La_0.4TiO₃,when the annealing temperature was between 800?and 900?,hexagonal phase La₂O₃ was appeared.The pH of the reaction environment was between 1 and 5,the sample contained TiO₂,when the pH was between 7 and 9,pure cubic phase Sr_0.6La_0.4TiO₃ was obtained.The phosphor could be effectively excited by the visible light of466nm to emit red light.After optimizing the experimental conditions,the optimum annealing temperature of Sr_0.6La_0.4TiO₃:Eu³⁺phosphor was determined to be 750°C,the optimum reaction environment pH was 9,and the optimum Eu³⁺doping amount was 11%,at this time the corresponding chromatic coordinate value was?0.623,0.376?,which was relatively close to the NTSC standard value?0.670,0.330?.A series of perovskite Ba_1-xLa_xTi O₃:Eu³⁺?x=0,0.5,0.7,0.8,1?phosphors were prepared by sol-gel method.Through excitation and emission spectra analysised a series of phosphors,it was found that when La:Ba was0.5:0.5,the phosphor Ba_0.5La_0.5TiO₃:Eu³⁺had the best luminous properties,so Ba_0.5La_0.5TiO₃:Eu³⁺phosphors had been detailedly studied.When the pH was1,the sample contained Ba La₂Ti₂O₈;when the p H was more than or equal to3 could obtain the orthorhombic Ba_0.5La_0.5TiO₃.When the annealing temperature was between 800?and 900?,orthogonal Ba_0.5La_0.5TiO₃ was obtained.The Ba_0.5La_0.5TiO₃:Eu³⁺phosphor emited red light under visible light excitation at 466 nm.When the annealing temperature of Ba_0.5La_0.5Ti O₃:Eu³⁺phosphor was determined to be was 800°C,the reaction environment pH was 3,and the Eu³⁺doping amount was 9%,Ba_0.5La_0.5TiO₃:Eu³⁺phosphor emited strong red light.Perovskite NaGdTiO₄:Eu³⁺phosphor was prepared by sol-gel method.The results showed that when the reaction environment pH was 1,there was Gd₂O₃ in the sample.Orthogonal NaGdTiO₄ was obtained.at the reaction environment pH between 3 and 9.When the annealing temperature was 500?and 600?,the sample contained triclinic Ti₈O₁₅,when the annealing temperature was between 700?and 900?could obtain NaGdTiO₄.NaGdTiO₄:Eu³⁺phosphor could be excited by 397nm UV light to emit red light.After optimizing the experimental conditions,it was determined that the orthogonal phase NaGdTiO₄:Eu³⁺phosphor had a strongest luminescence when the pH was 5,the annealing temperature was 800°C,and the Eu³⁺doping amount was 13%.At this time the corresponding chromatic coordinate value was?0.625,0.373?.In this paper,the perovskite type titanate Ba_xSr_1-xTiO₃,Sr_1-xLa_xTiO₃,Ba_1-xLa_xTi O₃,NaGdTiO₄ were used as matrix and Eu³⁺as an activator.Ba_0.77Sr_0.23TiO₃:Eu³⁺,Sr_0.6La_0.4TiO₃:Eu³⁺,Ba_0.5La_0.5TiO₃:Eu³⁺,NaGdTiO₄:Eu³⁺red luminous materials were prepared with sol-gel method.It provides information to enrich the field of rare earth luminescent materials and broaden the application range of titanates.