Chemical Engineering Journal, Vol.310, 91-101, 2017
Novel synthetic strategy towards BaFCl and BaFCl:Eu2+ nanofibers with photoluminescence properties
BaFCl and BaFCl:Eu2+ nanofibers have been successfully synthesized by one-step calcination of electrospinning-made PVP/Ba(CH3COO)(2) and PVP/[Ba(CH3COO)(2)+Eu(NO3)(3)] composite nanofibers via a double crucible fluoro-chlorination method using ammonium hydrogen fluoride and ammonium chloride as fluorination and chlorination sources, respectively. The as-prepared samples have been characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM) and fluorescence spectrophotometer. XRD analysis reveals that BaFCl and BaFCl:Eu2+ nanofibers are pure tetragonal phase with space group of P4/nmm. SEM and TEM observation indicate that the as-prepared samples possess distinct fibrous morphology, and the diameters of PVP/Ba(CH3COO)(2), PVP/[Ba(CH3COO)(2)+Eu(NO3)(3)] composite nanofibers, BaFCl, and BaFCl:Eu2+ nanofibers are 245 +/- 3, 266 +/- 3, 146 +/- 2, and 193 +/- 1 nm, respectively, which are analyzed by Gaussian statistics under the confidence level of 95%. Photoluminescence (PL) analysis manifests that BaFCl:Eu2+ nanofibers exhibit the characteristic blue emission of predominant peak at 387 nm and weak emission at 365 nm respectively originating from 4f(6)5d -> S-8(7/2) and P-6(7/2) -> S-8(7/2) energy levels transitions of Eu2+ under the excitation of 275-nm ultraviolet light, and the optimum molar concentration of Eu2+ is 8%. The formation mechanism of BaFCl:Eu2+ nanofibers is also advanced. More importantly, this preparation technique is of universal significance, and can be applied to prepare other alkaline earth metallic fluoro-halide nanofibers. (C) 2016 Elsevier B.V. All rights reserved.