Preparation And Properties Of Dy³⁺, Tm³⁺ Activated ABaPO₄ (A=Li⁺, Na⁺, K⁺) White Phospho

In this thesis,a series of ABaPO₄:RE³⁺(A=Li⁺,Na⁺,K⁺;RE³⁺=Tm³⁺,Dy³⁺)white phosphors were synthesized by high temperature solid state method.The crystal structures were confirmed by X-ray diffraction,SEM and EDS,fluorescence spectroscopy and chromaticity coordinates were measured to characterize luminescence properties of the prepared phosphors.For NaBaPO₄:Tm³⁺,Dy³⁺series phosphors,the effect of calcination temperature on main crystal structure was first studied.The following phosphors were prepared at the reaction temperature of 950℃:NaBa_0.97PO₄:0.03Dy³⁺,NaBa_0.95PO₄:0.01Tm³⁺,0.04Dy³⁺,NaBa_0.95PO₄:0.01Tm³⁺,0.04Dy³⁺,0.01H₃BO₃,NaBa_0.95PO₄:0.01Tm³⁺,0.04Dy³⁺,0.01CaF₂and NaBa_0.95PO₄:0.01Tm³⁺,0.04Dy³⁺,0.01Mg F₂ phosphors.XRD results show that the main crystal structure of these phosphors are NaBaPO4.NaBa1-x PO4:x Dy³⁺（x=0.005,0.01,0.02,0.03,0.05,0.07）phosphors emit cool white light,and NaBa1-y PO4:y Tm³⁺（y=0.005,0.01,0.02,0.03,0.05,0.07）phosphors emit blue light.For NaBaPO4:Tm³⁺,Dy³⁺series co-doping phosphors,the emission intensity of NaBa0.95PO4:0.01Tm³⁺,0.04Dy³⁺phosphor was the maximum,the color coordinates were（0.3192,0.2951）,which were the closest to ideal white light,and the average fluorescence lifetime was 0.61ms.The energy transfer mechanism between Tm-Dy in NaBaPO4 host was analyzed as dipole-dipole in multipole interaction.Both in terms of emission intensity and emission color,the phosphors were clearly optimized by the doping of CaF2 and Mg F2.The luminescent properties of the phosphors had not been optimized by the doping of H3BO3.CaF2 had the best optimization effect.The following phosphors were prepared under the same reaction conditions:KBa_0.99PO₄:0.01Dy³⁺,KBa_0.99PO₄:0.01Dy³⁺,0.04H₃BO₃,KBa_0.99PO₄:0.01Dy³⁺,0.06CaF₂and KBa0.99PO4:0.01Dy³⁺,0.03Mg F2 phosphors,and XRD results show that the main crystal structure of these phosphor are KBaPO4.KBa0.99PO4:0.01Dy³⁺had the highest luminescence intensity,and the color coordinates of KBa0.995PO4:0.005Dy³⁺phosphor were（0.3217,0.3317）,which were closest to ideal white light.The mechanism of the concentration quenching of Dy³⁺in KBaPO4 host was the resonance transfer of multipole interaction.The emission intensity and emission color of KBaPO4:Dy³⁺phosphors were significantly improved due to the doping of three fluxes,H3BO3,CaF2 and Mg F2.The crystal structure of the phosphors was not affected by the doping of fluxes.Combined with the analysis of emission intensity and luminescence color,the phosphors were most significantly improved by Mg F2.When the doping concentration of Mg F2 is 0.01,the color coordinates of the phosphor are（0.3312,0.3394）,which is closest to ideal white light.The remaining fluxes are ranked as CaF2,H3BO3 in order of improvement effect.The following phosphors were prepared under the same reaction conditions as the previoustwoseriesofphosphors:Li Ba0.96PO4:0.04Dy³⁺,Li Ba0.96PO4:0.04Dy³⁺,0.01H3BO3,Li Ba0.96PO4:0.04Dy³⁺,0.01CaF2and Li Ba0.96PO4:0.04Dy³⁺,0.01Mg F2 phosphors.XRD results show that the main crystal structure of these phosphor are LiBaPO4.Li Ba0.96PO4:0.04Dy³⁺phosphor has the strongest luminescence intensity,and the color coordinates are（0.3284,0.3384）,which is closest to ideal white light.The mechanism of concentration quenching of Dy³⁺in LiBaPO4 host is resonance transfer of multipole interaction.The three fluxes have better effects on the optimization of the emission intensity of Li Ba0.96PO4:0.04Dy³⁺phosphors,and the addition of fluxes does not affect the crystal structure of the Li Ba0.96PO4:0.04Dy³⁺phosphors.However,the luminescence color of LiBaPO4:Dy³⁺phosphors shifted from white region to yellow light region due to the addition of fluxes.In terms of emission color,when the doping concentration of H3BO3 is 0.01,the color coordinates of the Li Ba0.96PO4:0.04Dy³⁺phosphor are（0.3362,0.3552）,which is the closest to the ideal white light.In terms of emission intensity,CaF2 has the best optimization effect,and CaF2has the best optimization effect comprehensively.