Study of the structural, optical, electrical and electrochemical properties of copper oxide thin films synthesized by spray pyrolysis

In our present study we focus on characterizing copper oxide (CuO) thin films synthesized at various substrate temperatures and to assess the electrochemical performance of the optimized sample. The spray pyrolysis method was used to fabricate CuO thin film samples, with the substrate temperatures ranging from 250 to 400 degrees C. The coatings underwent characterization through different analytical techniques, including X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurements. All the thin film samples were confirmed to have a monoclinic phase. The presence of Cu=O was confirmed by Raman spectroscopy. All the samples exhibited P type conductivity except the one synthesized at 400 degrees C. Galvanostatic charge-discharge studies revealed a pseudocapacitive nature for the optimized sample synthesized at 350 degrees C. The symmetrical charging and discharging curves imply excellent material reversibility, indicating long-term cyclic stability. The Nyquist plot exhibited a semicircle at high frequencies, representing the material's intrinsic resistance and a linear behavior at low frequencies, depicting the ion transfer resistance. The electrode demonstrated favorable electrochemical properties and potential use of the material in supercapacitor applications.