Y_2O_2S:Yb~(3+), Er~(3+) nanofibers: novel fabrication technique, structure and up-conversion luminescent characteristics

摘要

Y_2O_3:Yb~(3+), Er~(3+) nanofibers were prepared by calcination of the electrospun poly vinyl pyrrolidone (PVP)/ [Y(NO_3)_3 + Yb(NO_3)_3 + Er(NO_3)_3] composite nanofibers. For the first time, Y_2O_2S:Yb~(3+), Er~(3+) up-conversion luminescent nanofibers were successfully synthesized via inheritance of the morphology and sulfurization of the above electrospinning-derived Y_2O_3:Yb~(3+), Er~(3+) nanofibers using sulfur powders as sulfur source by a double-crucible method we newly proposed. XRD analysis indicates that Y_2O_2S:Yb~(3+), Er~(3+) nanofibers are pure hexagonal in structure with space group P3m1. Observation results of FESEM and TEM reveal that the diameters of Y_2O_2 S:Yb~(3+), Er~(3+) nanofibers are 105 ± 13 nm, and Y_2O_2 S:Yb~(3+), Er~(3+) nanofibers are composed of nanoparticles with the diameter ranging from 40 to 70 nm. Up-conversion emission spectrum analysis manifests that Y_2O_2 S:Yb~(3+), Er~(3+) nanofibers exhibit strong green and red up-conversion emission centering at 526, 548 and 668 nm, respectively. The green emissions and the red emission are respectively assigned to ~2H_(11/2)/~4S_(3/2) → ~4I_(15/2) and ~4F_(9/2) → ~4I_(15/2) energy levels transitions of Er~(3+) ions. The formation mechanism of Y_2O_2S:Yb~(3+), Er~(3+) upconversion luminescence nanofibers is also proposed. More importantly, this new strategy and fabrication technique are of universal significance to prepare other rare earth oxysul-fides with various morphologies.