Sustainable electrochemical growth of highly oriented (-111) CuO absorber layers for optoelectronic applications

CuO layers were successfully synthesized via the electrodeposition on ITO/glass substrates.This study investigates the influence of annealing temperature and precursor concentration on their physical properties. The structural properties were analyzed using X-ray diffraction (XRD), revealing the formation of polycrystalline CuO with a dominant tenorite phase and a preferred orientation along the (-111) plane. Optical properties were examined using UV–visible spectrophotometry, which indicated a transmission smaller than 3 %. The optical band gap of the CuO thin films, estimated from Tauc plots derived from UV–Visible absorption spectra, was found to decrease from 1.72 eV to 1.59 eV as the annealing temperature increased from 400 °C to 500 °C, indicating an improvement in crystallinity and a reduction in structural defects. Morphological analysis using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy demonstrated a high granulation density and confirmed the presence of copper and oxygen elements. The layer annealed at 500°C exhibited particularly well defined morphology. These findings suggest that CuO thin layers are promising candidates for use as absorbers in solar cell applications due to their favorable structural and optical properties.