文摘
In this study, α-TeO2:Houp>3+up>/Ybup>3+up>, α-TeO2:Euup>3+up> and α-TeO2:Houp>3+up>/Ybup>3+up>/Euup>3+up> 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-TeO2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence. The α-TeO2:Houp>3+up>/Ybup>3+up> nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation, ascribed to the up>5up>S2→up>5up>I8 and up>5up>F5→up>5up>I8 (Houp>3+up>) transitions, and weaker down-conversion emission at 545 nm under 455 nm excitation, ascribed to the up>5up>S2→up>5up>I8 (Houp>3+up>) transitions. The α-TeO2:Euup>3+up> nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation, attributed to the up>5up>D0→up>7up>F1 and up>5up>D0→up>7up>F2 (Euup>3+up>) transitions. Possessing the advantages of these two luminescent materials, the as-prepared tri-doped samples of α-TeO2:0.5Houp>3+up>/10Ybup>3+up>/3Euup>3+up> (mol.%) nanoparticles could successfully emit visible light via both up- and down-conversion modes.