Study On Preparation And Photoluminescence Properties Of KBaIn₂?PO₄?₃ Phosphors

Rare earth phosphate phosphors,as one of the inorganic luminescent materials,have been the research focus of luminescent materials because of their good thermal stability,chemical stability,and good absorption in the ultraviolet region.In recent years,many rare earth phosphate phosphors with excellent performance have been researched and have great applications in the LED lighting and liquid crystal display.In this,thesis,phosphate KBaIn2(PO4)3 is used as a matrix material,and KBaIn2(PO4)3?Eu3+,Tb3+doped KB aIn2(PO4)3 phosphors and Dy3+,Tm3+ doped KBaIn2(PO4)3 phosphors were prepared by solid-state reaction and using X-ray diffraction data and Rietveld method to carry out phase analysis and structural refinement analysis,and scanning electron microscope,photoluminescence spectroscopy,ultraviolet-visible diffuse reflection spectroscopy,fluorescence decay life,quantum yield and other detection methods were used to analyze the morphology,luminescence performance and practicality of phosphors.The preparation process for the synthesis of KBaIn2(PO4)3 matrix was successfully formulated by the high-temperature solid-phase synthesis.The X-ray structure analysis revealed that the KBaIn2(PO4)3 compound belongs to the cubic group with the P213(No.198)space group.Under the excitation of ultraviolet,KBaIn2(PO4)3 matrix has strong broadband emission in the visible light region,indicating that it is a self-activated luminescent material.Under the excitation of ultraviolet light,the electrons in the valence band in the KBaIn2(PO4)3 matrix will jump to the conduction band and recombine with the holes in the conduction band,releasing photons,and showing broadband emission in the visible light region.The result shows that the KBaIn2(PO4)3 matrix is a self-activated luminescent material.Under the excitation of ultraviolet,the characteristic transitions of KBaIn2(PO4)3:Eu3+ and KBaIn2(PO4)3:Tb3+ phosphors attributed to the 5D0?7F2 transition of Eu3+and 5D4?7F5 of Tb3+ emit red light(612nm)and green light(541nm),respectively.The red-orange-yellow-green light color regulation can be achieved by adjusting the two ion concentrations.Through calculating fluorescence lifetime,energy transfer efficiency and plotting energy level diagram,the energy transfer process in Eu3+ and Tb3+co-doped phosphors is analyzed and discussed.The analysis of the high-temperature fluorescence spectrum shows that the emission intensity of the co-doped phosphor at 150? is still 68.75%at room temperature,and has excellent thermal stability.Under blue light excitation,KBaIn2(PO4)3:Dy3+ phosphor emits yellow light generated by the 4F9/2?6H13/2 transition.Under near ultraviolet excitation,KBaIn2(PO4)3:Dy3+phosphor emits from 4F9/2?6H15/2 composite white light produced by characteristic emission and matrix emission.Spectral analysis results show that the concentration quenching mechanism of KBaIn2(PO4)3:Dy3+ phosphor under the excitation of blue light and near ultraviolet light is the multi-level resonance mechanism and reabsorption mechanism respectively.By adjusting the concentration of the two ions of Dy3+ and Tm3+,the light color from blue light to white light was adjusted,and it was found that there is effective energy transfer in the co-doped phosphors of Dy3+and Tm3+.