title: Color-tunable nanophosphors by co-doping flame-made Y2O3with Tb and Eu.
abstract: Rare-earth phosphors with tunable optical properties are used in display panels and fluorescent lamps and have potential applications in lasers and bio-imaging. Here, non-aggregated Y2O3nanocrystals either doped with Tb3+(1-5 at%) or co-doped with Tb3+(2 at%) and Eu3+(0.1-2 at%) ions are made in one-step by scalable flame spray pyrolysis. The morphology of these nanophosphors is investigated by X-ray diffraction, electron microscopy and N2adsorption while their optical properties are monitored by photoluminescent spectroscopy. When yttria nanocrystals are doped with terbium, a bright green emission is obtained at an optimum Tb-content of 2 at%. When, however, europium is added, the emission color of these Tb-doped yttria nanophosphors can be tuned precisely from green to red depending on the Tb/Eu ratio. Furthermore, energy-transfer from Tb3+to Eu3+is observed, thus allowing the control of the excitation spectra of the co-doped nanophosphors.
authors.affiliation: Particle Technology Laboratory, Institute of Process Engineering Department of Mechanical and Process Engineering, Sonneggstrasse 3, CH-8092 Zurich, Swiss Federal Institute of Technology, ETH Zurich, Switzerland.
authors.forename: Georgios A
authors.initials: GA
authors.lastname: Sotiriou
authors.forename: Melanie
authors.initials: M
authors.lastname: Schneider
authors.forename: Sotiris E
authors.initials: SE
authors.lastname: Pratsinis
keywords: energy transfer; light emitting materials; nanoparticles; yttrium oxide