Synthesis of nickel-doped iron oxide nanoparticles by Co-precipitation method and investigation of its structural and opto-electronic properties

This paper is dedicated to the synthesis of nickel doped iron oxide nanoparticles and their characterization. We investigate the effect of doping Ni2+ ions on structural and opto-electronic properties of magnetite (Fe3O4) nanoparticles. In nature, iron oxides are available in three phases : Fe3O4, cFe203 and aFe203. Iron oxides are a very important transition metal oxides as for as their applications are concerned. Nanoparticles are characterized using FTIR, Raman and UV-vis-nir spectroscopic techniques. Imaging of samples is done by SEM for the morphological analysis. Increase in nickel concentrations reduces average crystallite size. Structural and opto-electronic properties of pure Fe3O4 and Ni-doped Fe3O4 (with varying concentrations of nickel i.e. 1.4 wt%, 4.2 wt%, 7.0 wt%, and 9.7 wt% by Fe content) have been investigated. The formation of different size nano-particles as well as their aggregates e.g. micro-structured nano-rods and nano-sheets has been confirmed from our SEM and HR-XRD data. UV-vis-nir data further confirms for the variable band-gaps which is a direct consequence of the particle size variation and its composition. We observe two band gap values in the visible range and two band-gap values in the infra-red region. Band-gaps in the visible range for 1.4 wt% are found to be 2.408 eV, 2.024 eV, respectively. The band-gaps in the visible range for 9.7 wt% are found to be 2.305 eV, 1.908 eV respectively. Band gaps in the infra-red region for 1.4 wt%, have values 1.631 eV, 1.439 eV respectively. The band gaps in the infra-red region for 9.7 wt% are found to be 1.597 eV, 1.419 eV respectively. These data suggest two prominent sizes each of nano-particles having energy band-gaps in both visible and infra-red regions. The inference drawn using SEM, HR-XRD and UV-vis-nir are found to be in good coherence, and are complementary to each other. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of 2022 International Conference on Recent Advances in Engineering Materials.