Effect of Co substitution on the structural and optical properties of ZnO nanoparticles synthesized by sol–gel route

Co doped ZnO nanoparticles were synthesized by sol–gel method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), UV–Visible absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). XRD analysis revealed the formation of single phase structure of all samples which was further supported by FTIR data. With the increase in Co concentration from 0% to 5%, crystallite size was observed to vary from 27.1 to 21.3 nm. It suggests the prevention of crystal growth as a result of Co doping in ZnO. It was also evident from the absorption spectra that the absorbance tends to increase with the increase in dopant concentration. Optical band gap was found to increase slightly with the increase in Co content, confirming the size reduction as a result of Co doping.

► This paper reports the optical properties of cobalt doped zinc oxide nanoparticles.
► It has been observed that cobalt successfully replaces the zinc in the doped samples.
► As a result of increase in cobalt concentration there has been an increase in band gap and decrease in particle size.