Electric field induced formation of one-dimensional bismuth ferrite (BiFeO3) nanostructures in electrospinning process

We report the characteristic influence of applied-voltage on the fabrication of one-dimensional fiber nanostructures of bismuth ferrite (BiFeO3/BFO) in electrospinning process. The applied voltage of 8 kV is found to be the threshold voltage for the formation of BFO fibers. The further systematic variation of voltages such as 10 kV, 15 kV and 20 kV yielded smaller broken-fibers that appeared to be rod-like nanostructures, lengthy-ordered fibers, and belt-like nanostructures respectively. The crystal phase analysis by X-ray diffraction technique revealed the rhombohedral perovskite structure of BFO. The average diameter/thickness of rods, fibers and belts is estimated from their FESEM and HRTEM images and it found to be 90-150 nm, 100-200 nm and 100-150 nm respectively. The optical and magnetic studies by UV-visible spectrometer and SQUID magnetometer respectively revealed the dimension dependent optical properties, where their magnetic properties are found to be in the order of belts > rods > fibers > aggregated fibers. The formation of fibers is initiated with the evolution of electrified jet; where the variation in the applied voltage causes bending and whipping instability in the electrified jet that presumably determined the morphological and compositional structures of fibers. (C) 2016 Elsevier Ltd. All rights reserved.