Study Of Synthesis And Property Of Europium Ion Doped Silicate Phosphor

Rare-earth doped phosphors are used in light and display devices widely.Selecting suitable host lattice and activator and synthesis method is very important to the development and improvement of phosphors.Silicate owns various structures,brilliant physical and chemical property,good thermal stability,water resistance,and lower synthesis temperature and easy accessible raw material compared with aluminate,thus silicate is very suitable to be the host lattice of phosphor.Europium ion owns abundant energy level transitions,moreover,these transitions are sensitive to the structure environment,it is possible and convenient to acquire different luminescence color by adjusting host lattice or doping concentration,thus europium ion is one of the most suitable activators.In this paper,a series of europium ion doped barium silicate was synthesized and the structure,morphology and luminescent property of these phosphors were study through XRD,photoluminescence spectrum,SEM,TEM,fluorescent microscope,fluorescence lifetime and quantum yield characterizations.Ba₂Si₄O₁₀:Eu³⁺phosphor was synthesized by solid state method for the first time and the structure of Ba₂Si₄O₁₀ and the possible concentration quenching mechanism was studied.The research revealed that Ba₂Si₄O₁₀:Eu³⁺phosphor owns two different structure,one is low-temperature orthogonal structure,the other is high-temperature monoclinic structure,and high-temperature phase was acquired at 1250?.The emission spectra at different temperature of Ba₂Si₄O₁₀:Eu³⁺phosphor indicated that the high-temperature phase is more asymmetric than low-temperature phase.The photoluminescence spectra with different Eu³⁺ion concentration revealed that when the doping concentration was 0.02,Ba₂Si₄O₁₀:Eu³⁺phosphor owned the best luminescent property with average fluorescence lifetime 1.0837ms,quantum yield 31.64%,and critical distance 28.52?.The reason responsible for concentration quenching is multipole-multipole interaction of non-radiation transitionMeanwhile,Ba₅Si₈O₂₁:Eu²⁺,Nd³⁺phosphor was synthesized by so-gel method for the first time,as for the Ba₅Si₈O₂₁:Eu²⁺,Nd³⁺phosphor,the particle size and distribution prepared were smaller and more homogeneous compared with solid state method,and the agglomeration and overlap phenomenon was less.The excitation and emission wavelength was 341nm and 489nm,the intensity of photoluminescence spectra reached the highest when the Nd³⁺ion doping concentration was 0.04.Ba₅Si₈O₂₁:Eu²⁺,Nd³⁺phosphor can be excited by sunlight directly and its afterglow lasted for 4 hours,the process of afterglow had rapid and slow decay process and its decay curves matched with the double-exponential function.Moreover,this phosphor owned a good water resistance.Lastly,PVP and Ba₅Si₈O₂₁:Eu²⁺,Nd³⁺phosphor was combined to synthesize luminescent fiber by electrospinning method,this fiber is rather flexible.The diameter of fiber is around 2?m.Ba₅Si₈O₂₁:Eu²⁺,Nd³⁺phosphor particles size was around 0.5?m and dispersed randomly into the fiber.The excitation and emission wavelength of the fiber were341nm and 489nm,and the phosphorescent emission wavelength was also 489nm.The fiber owned fine afterglow property and it lasted beyond 45 minutes.