Impact of iron doping on structural and optical properties of nickel sulphide nanoparticles

Abstract

Abstract Transition metal sulphides exhibit excellent optical, photo electrical and thermoelectric properties. These materials have attracted much attention because of its applications in the field of electroluminescence devices, light emitting displays, cathode material for rechargeable lithium battery, magnetic devices, dye degradation and optical sensors. In the present work, iron doped Nickel sulphide nanoparticles are synthesized using chemical precipitation method. Nickel chloride and Ferric chloride are used as precursors and sodium sulphide as a stabilizing agent. The performance of the synthesized nanoparticles are analysed by varying the molarity of the iron chloride from 0.01\xa0M to 0.05\xa0M. The synthesized nanoparticles are characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet Visible spectroscopy (UV–Vis) and Photoluminescence (PL) studies. FT-IR spectral analysis shows the band at 630\xa0cm−1 corresponds to the bending vibration of metal sulphur bond (Ni-S) and the bands observed around 585\xa0cm−1 and 456\xa0cm−1 are ascribed to Fe–O stretching vibrations of tetrahedral and octahedral lattice sites respectively. The XRD analysis shows the crystalline nature of nanoparticles and the average nano-crystallite size is found to be 18\xa0nm − 26\xa0nm. The crystallite size increases with increase in the concentration of iron. The morphology of the samples is analyzed using scanning electron microscope and is found to be spherical in shape. The optical properties are characterized using UV–Vis spectral analysis and PL study. UV–Visible absorption spectra show absorption peaks of iron doped nickel sulphide nanoparticles and the band exhibits a blue shift, indicates quantum size effect. Electrochemical studies revealed two oxidation peaks at a potential about −0.3\xa0V and 0.7\xa0V for pure nickel sulphide nanoparticles and in addition to it, a redox peak is observed at a potential about −0.5\xa0V due to the doping of iron into the nickel sulphide nanoparticles. The synthesized nanoparticles may be used as high-performance electrode materials for supercapacitor applications.