Morphology evolutions and optical properties of Cu ₂ O films by an electrochemical deposition on flexible substrate

Micro crystals of cuprous oxide (Cu ₂ O) with different morphologies, evolving from cubes, tetrahedrons, truncated cubes and final to truncated octahedrons, were obtained on indium tin oxide (ITO) flexible substrate (polyethylene terephthalate-PET) by simply adjusting the electrochemical deposition time. We elucidated the underlying morphology evolution mechanism using the cyclic voltammogram (CV), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical properties of Cu ₂ O films were characterized by the ultraviolet-visible (UV-vis) spectrum, which demonstrated the band gap changing from 2.21 eV to 2.43 eV with different electrochemical deposition time owing to the quantum confinement effect.