Abstract: In this paper, Na3ZrF7:Er/Yb nanoparticles (NPs) with core-shell structures were prepared by pyrolytic process , the morphologies , phase and emission spectra of all samples were analyzed .The emission intensity of the Na 3 ZrF7:Er3+2;, Yb3 +20;@CaF2 NPs was enhanced 5 times compared with that of Na3 ZrF7:Er3 +2;, Yb3 +20; under excitation of 980 nm.By coating the tetragonal Yb/Nd codoped NaYF4 on Na3 ZrF7:Er3 +2;, Yb3 +20;@CaF2 NPs, strongly upconverted red emissions of Na3 ZrF7@CaF2@NaYF4 NPs excited by an 808 nm laser were achieved , the red/green emission ratio approached a value of 10, the luminescence mechanism were elucidated .

Key words: In this paper, Na3ZrF7:Er/Yb nanoparticles (NPs) with core-shell structures were prepared by pyrolytic process , the morphologies , phase and emission spectra of all samples were analyzed .The emission intensity of the Na 3 ZrF7:Er3+2;, Yb3 +20;@CaF2 NPs was enhanced 5 times compared with that of Na3 ZrF7:Er3 +2;, Yb3 +20; under excitation of 980 nm.By coating the tetragonal Yb/Nd codoped NaYF4 on Na3 ZrF7:Er3 +2;, Yb3 +20;@CaF2 NPs, strongly upconverted red emissions of Na3 ZrF7@CaF2@NaYF4 NPs excited by an 808 nm laser were achieved , the red/green emission ratio approached a value of 10, the luminescence mechanism were elucidated .