Y2O2S:Yb3+, Er3+ nanofibers: novel fabrication technique, structure and up-conversion luminescent characteristics

Y2O3:Yb3+, Er3+ nanofibers were prepared by calcination of the electrospun polyvinyl pyrrolidone (PVP)/[Y(NO3)3 + Yb(NO3)3 + Er(NO3)3] composite nanofibers. For the first time, Y2O2S:Yb3+, Er3+ up-conversion luminescent nanofibers were successfully synthesized via inheritance of the morphology and sulfurization of the above electrospinning-derived Y2O3:Yb3+, Er3+ nanofibers using sulfur powders as sulfur source by a double-crucible method we newly proposed. XRD analysis indicates that Y2O2S:Yb3+, Er3+ nanofibers are pure hexagonal in structure with space group \( {\text{P}}\overline{ 3} m 1 \). Observation results of FESEM and TEM reveal that the diameters of Y2O2S:Yb3+, Er3+ nanofibers are 105 ± 13 nm, and Y2O2S:Yb3+, Er3+ nanofibers are composed of nanoparticles with the diameter ranging from 40 to 70 nm. Up-conversion emission spectrum analysis manifests that Y2O2S:Yb3+, Er3+ nanofibers exhibit strong green and red upconversion emission centering at 526, 548 and 668 nm, respectively. The green emissions and the red emission are respectively assigned to 2H11/2/4S3/2 → 4I15/2 and 4F9/2 → 4Il5/2 energy levels transitions of Er3+ ions. The formation mechanism of Y2O2S:Yb3+, Er3+ upconversion luminescence nanofibers is also proposed. More importantly, this new strategy and fabrication technique are of universal significance to prepare other rare earth oxysulfides with various morphologies.