Preparation And Luminescence Properties Of Novel Borate Phosphor

Phosphor and light-emitting diode combined to produce white light lighting devices have the characteristics of health and comfort,simple assembly technology and high energy efficiency,and the lighting devices are widely used in household lighting,electronic display and public walking lights and so on.The premise of these light-emitting devices that generate white light is to obtain phosphors with excellent luminescence properties.Therefore,the focus of phosphor research is to obtain phosphors with broadband excitation and emission,high quantum yield and single-phase white light.In this paper,around these research focus,the high-temperature solid-phase method is used as a means of preparing phosphors.Phosphors are prepared by adding Bi³⁺、Tb³⁺、Eu³⁺、Sm³⁺ions as activators on borate with stable chemical properties,high structural stiffness and mild synthesis conditions,and the properties are characterized.These phosphors include yellow phosphors with broadband excitation and emission or high quantum yield and blue excitation as well as single-phase white light.The research results are as follows:1.The yellow phosphors Gd₃BWO₉:Bi³⁺,Eu³⁺/Sm³⁺are successfully prepared on Gd₃BWO₉ substrate by co-doping of Bi³⁺and Eu³⁺ions or co-doping of Bi³⁺and Sm³⁺ions.Gd₃BWO₉:0.01Bi³⁺,0.04Eu³⁺/0.05Sm³⁺yellow phosphors have 200-340 nm excitation peak,and Bi³⁺ions produce 420-680 nm emission peak,and Sm³⁺and Eu³⁺have strong red light.Therefore,these luminous wavelength almost covers the whole visible spectrum,with potentially high color rendering index,which makes up for the lack of red component of Y₃Al₅O₁₂:Ce³⁺and avoids the need for reduction in the preparation process.Moreover,they are assembled with ultraviolet light-emitting diode to obtain white light diodes,which has very good practicability.2.Co-introduction of rare earth ions Tb³⁺-Sm³⁺or Tb³⁺-Eu³⁺to replace Gd³⁺ions on Gd₃BWO₉ substrate prepared yellow phosphors that can be excited by 487 nm blue light.Use Tb³⁺-Eu³⁺ions co-doped to prepare phosphor Gd₃BWO₉:0.25Tb³⁺,0.05Eu³⁺the quantum yield reaches 83.7%,and the corresponding yellow phosphor Gd₃BWO₉:0.25Tb³⁺,0.03Eu³⁺quantum yield reaches 70.2%.The thermal quenching activation energy of the yellow phosphor Gd₃BWO₉:0.25Tb³⁺and 0.03Eu³⁺is 0.26 e V by calculation and fitting from the variable temperature fluorescence test results from 298K to 473 K.Gd₃BWO₉:0.25Tb³⁺,0.03Eu³⁺phosphors that can be excited by blue light and have high quantum yield have potential applications.3.YAl₃（BO₃）₄:x Bi（x=0.01～0.10）phosphors are prepared by doping Bi in YAl₃（BO₃）₄.YAl₃（BO₃）₄:Bi phosphors have three broadband emission peaks:blue light at 350～500 nm,green light at 500～590 nm,and red light at 590～750 nm.In addition,when the doping concentration is 6%,the coordinates of YAl₃（BO₃）₄:0.06Bi on the CIE1931 chromaticity diagram are（0.33,0.32）,which are close to the standard iso-energy white light point（0.33,0.33）,and this indicates that the single-phase white phosphor YAl₃（BO₃）₄:0.06Bi are successfully prepared.On the basis of excitation and emission spectra,XPS and EPR tests show that Bi³⁺and Bi⁴⁺ions may exist in YAl₃（BO₃）₄:Bi phosphors.By only adding Bi element to the YAl₃（BO₃）₄ substrate,YAl₃（BO₃）₄:Bi phosphors with different luminescent colors and even white light emission can be obtained.Among them,the YAl₃（BO₃）₄:0.06Bi phosphors that can generate white light have potential application prospects.