Variations in the optical and thermoelectric behavior of ZnCo2O4 nanostructures as a function of synthesis temperature

Zinc cobalt oxide nanostructures were synthesized by electrochemical deposition of zinccobalt alloy at various bath temperatures (15, 30, 45 and 60 ˚C) and its hydrothermal oxidation at 100 ˚C. X-ray diffraction pattern and Raman spectroscopy data reveals the formation of spinal structure of ZnCo2O4. Photoluminescence spectra of the samples exhibit broad peaks with a red shift in the emission energy. Diffused reflectance spectroscopy measured the band gap of the synthesized materials; band gap is 3.06, 3.03, 3.02 and 2.99 eV, for samples electrodeposited at 15, 30, 45 and 60 ˚C, respectively. Optical conductivity of synthesized materials decreases with increasing deposition layers while reflectance shows opposite trend. Thermoelectric set up measures the change in potential difference through synthesized materials when different temperatures are applied and an increment in potential were observed. Seebeck co-efficient and power factor are also studied as function of bath temperature.