Correlation between molar concentration and properties of sprayed copper oxide thin films

Copper oxide precursor solutions containing 0.10 M, 0.15 M, 0.20 M and 0.25 M concentration of copper were deposited on a glass substrate using the spray pyrolysis method. The structural, optical and surface properties of the resulting copper oxide thin films were studied using x-ray diffraction, UV–visible spectroscopy and scanning electron microscopy. Structural studies indicate the absence of secondary phases of copper oxide in the spray-deposited copper oxide thin film with 0.10 M concentration. Optical characterization reveals highest absorbance and lowest transmittance at 0.10 M concentration with an estimated optical bandgap of 1.2 eV. The SEM micrographs reveals a non-porous and comparatively more homogenous surface at 0.10 M concentration. The results show that molar concentration of copper plays a vital role in the development of copper oxide (CuO) thin film for solar cell application. The results have further validated the theoretical predictions of the GW approximations on phases of copper oxide thin films.