Synthesis and characterization of cobalt-doped SiO2 nanoparticles

In the present work, Co-doped SiO2 nanoparticles are synthesized via the sol-gel method. X-ray diffraction (XRD) analysis indicates the formation of amorphous SiO2 nanoparticles and some additional peaks corresponding to the cobalt oxide (Co2O3) phase are also observed. The scanning electron microscope (SEM) analysis shows the spherical-shaped nanoparticles having particle size of 130-150 nm. Fourier transform infrared (FTIR) spectroscopy results show various absorption bands corresponding to typical stretching and/or bending vibrational modes. UV-Vis spectroscopy results indicate the low energy charge migration between the oxygen ligands and Co2+ ion in tetrahedral symmetry. By photoluminous spectroscopy analysis, the intensity of the blue band was observed to be enhanced significantly with the increasing Co concentration. This might be due to the formation of more defects sites in the host matrix. Moreover, the dielectric constant and AC conductivity of SiO2 nanoparticles were also influenced remarkably by increasing Co concentration.