Preparation And Luminescence Properties Of Rare-earth Ions Doped Molybdate Materials Under Near UV Excitation

White light emitting diode?LED? than ordinary solid lighting has a higher luminous efficiency, long fluorescence lifetime, lower energy consumption, environmental protection and stability etc., more and more be taken seriously.Rare earth ions by 4f-4f and 4f-5d transition to realize the polychromatic light.Molybdate with tetragonal crystal system structure, has a good stability when doped with rare earth ions.In this paper, by using hydrothermal synthesis of a series of rare earth ions doped molybdenum acid salt of polychromatic light and white light emission phosphors, and study its luminescent properties, mainly as follows:A series NaY?MoO₄?₂:Dy³⁺,Eu³⁺phosphors were synthesized by Sodium citrate assist hydrothermal method, NaY?MoO₄?₂:Dy³⁺ phosphor appeared the two characteristics of Dy³⁺ emission peak.In NaY?MoO₄?₂: Dy³⁺, Eu³⁺ samples, by changing the concentration of Eu3 + ions get warm white fluorescent powder.With the increase of the doping concentration of Eu³⁺, Eu³⁺ characteristic emission peak enhancement, and the characteristics of Dy³⁺ emission peak decrease.From Dy³⁺ the Eu³⁺ have energy transfer, energy transfer mechanism of quadrupole- quadrupole interaction.CIE coordinates figure show that when the amount of Eu³⁺ doping is y = 0.8, NaY?MoO₄?₂:5 % Dy³⁺, 0.8%Eu³⁺, the CIE coordinates?0.329, 0.329? is close to the white light of the standard color coordinates x = 0.33, y = 0.33.NaY?MoO₄?₂:5 % Dy³⁺, 0.8%Eu³⁺ is single substrate near ultraviolet excited white light phosphor.NaY?MoO₄?₂: Eu³⁺, Tb³⁺ phosphors was synthesized by hydrothermal method using sodium citrate assist under 283 nm excitation, appeared the characteristic emission peak of Tb³⁺and Eu³⁺ the characteristics of the emission peak.In NaY?MoO₄?₂: Eu³⁺, Tb³⁺ phosphors, MoO₄2- part of the energy transmitted to the Eu³⁺, part of the transfer to Tb³⁺.When the proportion of Tb³⁺/Eu³⁺ increases, NaY?MoO₄?₂: Tb³⁺, Eu³⁺ phosphor light from red light yellow to green light to move gradually.By adjusting the proportion of Tb³⁺/Eu³⁺ implements a single substrate of multicolor adjustable light, the phosphors with development prospects in the area of polychromatic light and display.Using solvent hot method have NaY?MoO₄?₂: Tb³⁺, Eu³⁺, Tm³⁺ phosphors, the Tb³⁺ and the doping amount of Tm³⁺ unchanged, by adjusting the concentration of Eu³⁺, can adjust the color of the light.The luminous intensity of Tb³⁺ and decreased with the increase of concentration of Eu³⁺, Tb³⁺ to give Eu³⁺ energy transfer.With the increase of the Eu³⁺ concentration, NaY?MoO₄?₂: Tb³⁺, Eu³⁺, Tm³⁺ phosphors emitting from green to white light emission.In NaY?MoO₄?₂: Tb³⁺, Eu³⁺ phosphor powder, the introduction of Tm3 +, increased the blu-ray ingredients, can achieve a single substrate of white light emission. CIE coordinates of NaY?MoO₄?₂:15% Tb³⁺, 4%Eu³⁺, 1% Tm³⁺?0.319, 0.319? close to the standard white light.The hydrothermal synthesis method for NaY0.95-xGdx?MoO₄?₂:5%Dy³⁺ phosphors.XRD showed that the preparation of Na?Y0.47, Gd0.48??MoO₄?₂:Dy³⁺5% Gd³⁺ the introduction of did not change the crystal structure.At 485 nm and 575 nm, respectively, have 4F9/2-6H15/2and4F9/2-6H13/2, the Dy³⁺characteristics of the launch, when the concentration of Gd³⁺ increased gradually, the phosphor emission intensity increased.When x = 0.48, there are the biggest launch.In the 276 nm, 352 nm and 276 nm inspired NaGd0.48 Y0.47?MoO₄? 2:0.05 Dy³⁺ phosphors CIE coordinates, respectively?0.409, 0.409?,?0.317, 0.317?,?0.316, 0.316?.Pink, cold white and yellowish light respectively.