Visible-light emission properties of α-TeO_2:Ho^(3+)/Yb^(3+)/Eu^(3+) nanoparticles via both up-and down-conversion modes

摘要

In this study,α-TeO_2:Ho^(3+)/Yb^(3+),α-TeO_2:Eu^(3+) and α-TeO_2:Ho^(3+)/Yb^(3+)/Eu^(3+) nanoparticles were prepared via a simple hydrothermal process.The up- and down-conversion properties of the as-prepared nanoparticles were tested at room temperature under a near-infrared photo source(980 nm) and UV-vis photo source,respectively.The results indicated that α-TeO_2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence.The α-TeO_2:Ho^(3+)/Yb^(3+) nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation,ascribed to the ~5S_2→~5I_8 and ~5F_5→~5I_8(Ho^(3+)) transitions,and weaker down-conversion emission at 545 nm under 455 nm excitation,ascribed to the ~5S_2→~5I_8(Ro^(3+)) transitions.The α-TeO_2:Eu^(3+)nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation,attributed to the ~5D_0→~7F_1 and^5D_0→~7F_2(Eu^(3+)) transitions.Possessing the advantages of these two luminescent materials,the as-prepared tri-doped samples ofα-TeO_2:0.5Ho^(3+)/10Yb^(3+)/3Eu^(3+)(mol.%) nanoparticles could successfully emit visible light via both up- and down-conversion modes.