Easy method to prepare copper oxides with good photocurrent values

Abstract

The influence of thermal annealing on the microstructure of copper oxide thin films has been investigated. The copper hydroxide (Cu(OH)2) nanowires were synthesized using a wet chemical (immersion) method. The aqueous solution was prepared by mixing 1 M NaOH and 0.1 M (NH4)2S2O8 and 30 ml of distilled water. The copper substrate was well polished, then immersed into the growth solution for 10 min, rinsed with distilled water, then dried in air, and finally annealed at different temperatures for 1 h in air. This structure can be used for many applications such as photoelectrochemical water splitting and photo-catalysis.The obtained materials were characterized by X-ray diffraction (XRD), Raman spectroscopy and Scanning electron microscopy (SEM).The results revealed the formation of cupric oxide (CuO) and cuprous oxide (Cu2O), observed on the surface of the thin films annealed at different temperatures. The morphology of these two oxides was found to depend on annealing temperature. The resulting of a copper-oxide (CuO) photoelectrode exhibited an enhanced photocurrent density under light illumination compared to the heterostructure (CuO and Cu2O) photoelectrode. This result indicates a good conductivity of the CuO phase and a good charge separation due to the band structure realignement at the interface.