Potassium element modulation of optical and electrical properties of the quasi-one-dimensional K_xBi_1-xFeO_3-y system

Structural and elemental modifications of multiferroics evolve promising optical, electronic and magnetic properties. In this work, we report two new quaternary compounds (K_xBi_1-xFeO_3-y) with nanowire and microrod structures synthesized based on potassium modification of BiFeO₃ by polyethylene glycol (PEG) and hexadecyl trimethyl ammonium bromide (CTAB) assisted hydrothermal method, respectively. The surfactants (PEG and CTAB) directed the growth of these two quasi-one-dimensional K _xBi_1-xFeO_3-y crystals. The structures of K _xBi_1-xFeO_3-y nanowire and microrod were addressed by electron-microscopy crystallography. The lattice constants were measured from the electron diffraction patterns to be a = b = 0.593 nm, c = 1.605 nm for the nanowire (tetragonal crystal) and a = 0.792 nm, b = 0.563 nm, c = 1.440 nm and β = 123.3° for the microrod (monoclinic crystal). Furthermore, the K_xBi_1-xFeO_3-y nanowires exhibited high conductivity while K_xBi_1-xFeO_3-y microrods demonstrated near-infrared fluorescence. This work is to expand the application of these promising multiferroic materials with new optical and electronic properties.