Effects of ammonia in the synthesis of copper (II) oxide nanostructures grown via microwave chemical bath deposition

In this study, CuO was grown on fluorine-doped tin oxide (FTO) substrates by depositing a copper (II) oxide seed layer via microwave chemical bath deposition while controlling the ammonia concentration. The morphological, optical, structural, electrical, and photoelectrochemical properties were measured by field emission scanning electron microscopy (FE-SEM), UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and three-electrode potentiostat measurements, respectively. The ammonia concentration affected the morphological and structural properties (i.e., the growth and thickness of the CuO nanostructures), the optical properties (i.e., optical energy bandgap), the electrical properties (i.e., the flat-band potential and acceptor density) and the photoelectrochemical properties of the prepared CuO samples. As a result, the highest photocurrent density of 2.05 mA/cm2 (at − 0.55 V vs. SCE) was obtained for the sample with an ammonia concentration of 0.16 M.