Dual - Mode Luminescence Of Rare Earth - Doped Core - Shell Nanomaterials

In this paper, the effects of shell structures on dual-modal luminescence of Na3 Zr F7:Yb3+,Er3+@ GdxZryF7:Eu3+(3x+4y=7) core-shell type nano-materials were mainly studied by structural and spectral analytic techniques.Firstly, Na3 Zr F7:Yb3+,Er3+ nanoparticles as core structures were synthesized at different reaction temperatures, then structurally and morphologically characterized by XRD and TEM. The effect of reaction temperature on upconversion luminescence intensity of Er3+ ions in Na3 Zr F7:Yb3+,Er3+ nanoparticles was investigated by fluorescence spectrophotometer under 980 nm light source excitation. The result shows that the upconversion luminescence intensities have been greatly improved with the increase of reaction temperature. The improved luminescence intensities are due to the increases of particle sizes.Secondly, Gd Zr F7:Eu3+ nanoparticles were synthesized with different Eu3+ doped concentrations(0.5-10 mol%). In our experiment, the luminescence intensity of Gd Zr F7:(2 mol%) Eu3+ is optimal under both 395 and 273 nm light source excitations.Finally, to study the effects of Gd3+ concentrations on dual-modal luminescence of core-shell nano-materials, Na3 Zr F7:Yb3+,Er3+@GdxZryF7:Eu3+ were synthesized with different Gd3+ concentrations. The results show that, on the one hand, the upconversion luminescence intensities of core-shell nano-materials, compared with that of Na3 Zr F7:Yb3+,Er3+, have been greatly improved under 980 nm light source excitation. On the other hand, characteristic Eu3+ emissions of core-shell nanomaterials are affected by Gd3+ doping concentrations under 395 nm light source excitation; Eu3+ emission intensities of core-shell nano-materials, under 273 nm light source excitation, have been enhanced with increasing the Gd3+ concentrations, which is due to the energy transfer from Gd3+ to Eu3+ ions.Conclusions, the as-prepared Na3 Zr F7:Yb3+,Er3+@GdxZryF7:Eu3+ core-shell nanomaterials are a functional material with dual-modal luminescence under IR and UV excitations, which have potential applications in such several fields as biomedicine, solar energy and false proof mark.