Fabrication of Y2O2S:Eu3+ hollow nanofibers by sulfurization of Y2O3:Eu3+ hollow nanofibers

Abstract

Y2O3:Eu3+ hollow nanofibers were prepared by calcination of the electrospun PVP/[Y(NO3)3 + Eu(NO3)3] composite nanofibers, and then Y2O2S:Eu3+ hollow nanofibers were successfully synthesized by sulfurization of the as-obtained Y2O3:Eu3+ hollow nanofibers via a double-crucible method using sulfur powders as sulfur source. The samples were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and fluorescence spectroscopy. XRD analysis shows that the Y2O2S:Eu3+ hollow nanofibers are pure hexagonal phase with the space group of P\( \bar{3} \)m1. SEM observation indicates that as-prepared Y2O2S:Eu3+ nanofibers are obvious hollow-centered structure with the mean outer diameter of 184 ± 26 nm. Under the excitation of 260-nm ultraviolet light, the Y2O2S:Eu3+ hollow nanofibers exhibit red emissions of predominant emission peaks at 628 and 618 nm originated from 5D0 → 7F2 energy levels transitions of Eu3+ ions. The luminescent intensity of Y2O2S:Eu3+ hollow nanofibers is remarkably increased with the increase of doping concentration of Eu3+ ions and reaches a maximum at 3 mol % of Eu3+ ions. The emitting colors of the samples are located in the red region in CIE chromaticity coordinates diagram. The possible formation mechanism of Y2O2S:Eu3+ hollow nanofibers is also proposed. This preparation technique could be applied to prepare other rare earth oxysulfide hollow nanofibers.