Terbium and ytterbium-doped titania luminescent nanofibers by means of electrospinning technique

Research highlights: → Tb and Yb-doped TiO2 nanofibers by the electrospinning technique → The EDS mappings attest the uniform distribution of Ti and Ln within the nanofibers → The rare earth doping delays the anatase to rutile phase transition up to 900 deg. C → Lanthanide-titanium oxide (Ln2Ti2O7) formation in the temperature range 900-1000 deg. C → Luminescence properties due to Tb3+ and Yb3+ ions 4f-transitions. - Abstract: The study of the luminescent properties of the rare-earth (RE) elements hosted in different crystalline matrixes is strongly motivated due to technological applications in optoelectronic devices and flat panel displays. In particular, it is known that nanostuctured titania (TiO2) is a promising host material for several trivalent rare earth ions. In this paper Tb- and Yb-doped titania nanofibers have been fabricated by electrospinning technique. A full characterization, is presented, including microstructural, thermal, spectroscopic and optical investigations. All electrospun materials consisted of randomly oriented nanofibers of fairly uniform diameter of 35 and 80 nm for, respectively, Tb-doped and Yb-doped TiO2. The incorporation of RE elements within the titania lattice resulted in a delayed anatase to rutile phase transition, accompanied by the formation Ln2Ti2O7 (Ln = Tb, Yb). All samples showed luminescent properties, the relative emission spectra were dominated by the typical Tb3+ and Yb3+ emission peaks associated to the specific Ln3+ 4f-transitions.