Luminescence properties and Judd–Ofelt analysis of SiO2:Ln3+ (Eu, Tb) hollow nanofibers fabricated by co-axial electrospinning method

Abstract

Novel luminescent one-dimensional Ln3+ (Eu, Tb) doped SiO2 hollow nanofibers were successfully fabricated using a facile and economical co-axial electrospinning technique with subsequent calcination. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the as-obtained samples present obvious hollow morphology with an average diameter of 303 ± 11 nm and thin walls approximate 76 nm. For SiO2:xEu3+ hollow nanofibers, the highest luminescence intensity, the longest lifetime and the largest quantum efficiency were both in the composition of 6 mol% Eu3+. The large value of R21 indicated a highly disordered environment around Eu3+ ions in the host, which was better for intense visible red emission. Meanwhile, the spectral characteristics and radiative properties were also analyzed according to the Judd-Ofelt theory from the emission spectra. What's more, under ultraviolet excitation, the emission colors of samples could be tuned from red to green, including bisque by doping Eu3+, Tb3+ and co-doping Eu3+/Tb3+ ions, which indicated the obtained SiO2:Ln3+ hollow nanofibers are potential phosphors in nanostructured optical devices applications.