A Comparative Investigation on the Structural, Optical and Electrical Properties of SiO2–Fe3O4 Core–Shell Nanostructures with Their Single Components

The SiO2–Fe3O4 core–shell nanostructures were synthesized by sol–gel chemistry. The morphological features of the nanostructures were examined by field emission scanning electron microscopy which revealed the core–shell nature of the nanoparticles. X-ray diffraction studies evidenced the formation of SiO2–Fe3O4 core–shell nanostructures with high degree of homogeneity. The elemental composition of the SiO2–Fe3O4 core–shell nanostructures was determined by energy-dispersive X-ray spectroscopy analysis. Fourier transform infrared spectroscopy showed the Si–O–Fe stretching vibrations. On analysis of the optical properties with UV–Vis spectra and Tauc’s plot, it was found that the band gap of SiO2–Fe3O4 core–shell nanostructures diminished to 1.5 eV. Investigation of the electrical properties of the core–shell nanostructures using field-dependent conductivity measurements presented a significant increase in photoconductivity as compared to those of its single components, thereby rendering them as promising candidates for application as photoelectrodes in dye-sensitized solar cells.