Electrospinning preparation and up-conversion luminescence properties of LaOBr:Er3+ nanofibers and nanoribbons

LaOBr:Er3+ nanofibers and nanoribbons were synthesized for the first time via calcinating the respective electrospun PVP/[La(NO3)(3) + Er(NO3)(3) + NH4Br] composites. The morphology, structure and luminescent properties of the final products were investigated in detail by field emission scanning electron microscopy (FESEM), energy dispersion spectroscopy (EDS), X-ray diffractometry (XRD) and fluorescence spectroscopy. The diameter of the LaOBr:Er3+ nanofibers with the pure tetragonal crystal phase are ca. 144.36 nm. The width and the thickness of LaOBr:Er3+ nanoribbons with the pure tetragonal in structure are ca. 5.66 mu n and 151 nm, respectively. Under the excitation of a 980-nm diode laser, LaOBr:Er3+ nanofibers and nanoribbons exhibit the characteristic up-conversion emissions of Er3+ ions, and the optimum doping concentration of Er3+ ions in the LaOBr:Er3+ nanofibers and nanoribbons is 3.0%. Interestingly, the luminescence intensity of LaOBr:Er3+ nanoribbons is obviously stronger than that of LaOBr:Er3+ nanofibers under the same measuring conditions. The color emissions of LaOBr:Er3+ nanostructures can be tuned from green emission to yellow emission by changing the concentration of doping Er3+ ions and the morphologies of nanostructures. Moreover, the predominant near-infrared emission at 1.50 mu m of LaOBr:Er3+ nanostructures are obtained under the excitation of a 532-nm laser. The formation mechanisms of LaOBr:Er3+ nanofibers and nanoribbons are also proposed. Electrospinning is a simple and efficient method for the synthesis of luminescent LaOBr:Er3+ nanostructures, which would be promising up-conversion luminescent nanomaterials. (C) 2014 Elsevier B.V. All rights reserved.