A sequence of NaCaGd(WO_(4))_(3):Tb^(3+),Eu^(3+)phosphors were prepared via a high temperature solid state reaction method.XRD,Rietveld refinement and SEM were carried out to identify the crystalline phase and morphol...A sequence of NaCaGd(WO_(4))_(3):Tb^(3+),Eu^(3+)phosphors were prepared via a high temperature solid state reaction method.XRD,Rietveld refinement and SEM were carried out to identify the crystalline phase and morphology.The photoluminescence properties of as-synthesized phosphors excited by ultraviolet light were studied in detail.According to the photoluminescence emission spectra and fluorescence decay curves,efficient energy transfer occurred in these Tb^(3+),Eu^(3+)co-doped NaCaGd(WO_(4))_(3)phosphors.The energy transfer efficiency reached up to 92.267%when the doping concentration of Eu^(3+)ions reached 0.4 mol,and the dominant energy transfer mechanism was determined to be the dipole–dipole interaction.The color tunability can be realized from green to red by adjusting the Tb^(3+)/Eu^(3+)doping ratio.Moreover,the representative NaCaGd(WO_(4))_(3):0.6Tb^(3+),0.1Eu^(3+)sample exhibited excellent thermal stability,and their emission intensity at 423 K still maintains about 84.7%of that at an initial temperature of 303 K.Ultimately,the as-packaged white LED device exhibited an outstanding correlated color temperature(CCT)of 4505 K and a color rendering index(Ra)of 87.3.The results mentioned above show that all the obtained phosphors are promising candidates in the fields of display devices and pc-WLEDs.展开更多
基金financially supported by the Jilin Provincial Research Foundation(Grant No.20200401057GX,20200401101GX)the Jilin Province Development and Reform Commission(No.2019C057-1)the Jilin Province Education Department Project(Grant No.JJKH20200760KJ,JJKH20200767KJ).
文摘A sequence of NaCaGd(WO_(4))_(3):Tb^(3+),Eu^(3+)phosphors were prepared via a high temperature solid state reaction method.XRD,Rietveld refinement and SEM were carried out to identify the crystalline phase and morphology.The photoluminescence properties of as-synthesized phosphors excited by ultraviolet light were studied in detail.According to the photoluminescence emission spectra and fluorescence decay curves,efficient energy transfer occurred in these Tb^(3+),Eu^(3+)co-doped NaCaGd(WO_(4))_(3)phosphors.The energy transfer efficiency reached up to 92.267%when the doping concentration of Eu^(3+)ions reached 0.4 mol,and the dominant energy transfer mechanism was determined to be the dipole–dipole interaction.The color tunability can be realized from green to red by adjusting the Tb^(3+)/Eu^(3+)doping ratio.Moreover,the representative NaCaGd(WO_(4))_(3):0.6Tb^(3+),0.1Eu^(3+)sample exhibited excellent thermal stability,and their emission intensity at 423 K still maintains about 84.7%of that at an initial temperature of 303 K.Ultimately,the as-packaged white LED device exhibited an outstanding correlated color temperature(CCT)of 4505 K and a color rendering index(Ra)of 87.3.The results mentioned above show that all the obtained phosphors are promising candidates in the fields of display devices and pc-WLEDs.
