Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ nanofibers: novel fabrication technique, structure and up-conversion luminescent characteristics

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Y^sub 2^O3:Yb^sup 3+^, Er^sup 3+^ nanofibers were prepared by calcination of the electrospun polyvinyl pyrrolidone (PVP)/[Y(NO3)^sub 3^ + Yb(NO3)^sub 3^ + Er(NO3)^sub 3^] composite nanofibers. For the first time, Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ up-conversion luminescent nanofibers were successfully synthesized via inheritance of the morphology and sulfurization of the above electrospinning-derived Y^sub 2^O3:Yb^sup 3+^, Er^sup 3+^ nanofibers using sulfur powders as sulfur source by a double-crucible method we newly proposed. XRD analysis indicates that Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ nanofibers are pure hexagonal in structure with space group ... Observation results of FESEM and TEM reveal that the diameters of Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ nanofibers are 105 ± 13 nm, and Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ nanofibers are composed of nanoparticles with the diameter ranging from 40 to 70 nm. Up-conversion emission spectrum analysis manifests that Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ 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 ^sup 2^H^sub 11/2^/^sup 4^S^sub 3/2^ [arrow right] ^sup 4^I^sub 15/2^ and ^sup 4^F^sub 9/2^ [arrow right] ^sup 4^I^sub l5/2^ energy levels transitions of Er^sup 3+^ ions. The formation mechanism of Y^sub 2^O2S:Yb^sup 3+^, Er^sup 3+^ 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.