Aligned 2-D Nanosheet Cu2O Film: Oriented Deposition on Cu Foil and Its Photoelectrochemical Property

Cuprous oxide (Cu 2 O) films on Cu foils with a two-dimensional (2-D) nanosheet structure were first synthesized by polyol method with the assistance of acetamide and copper acetate as the copper source. The characterization results show that the prepared Cu 2 O nanosheets which are aligned on the Cu foils are single crystal with the thickness of ∼20 nm. The addition of acetamide is crucial for the controllable synthesis of 2-D nanosheet structured Cu 2 O films. Without the presence of acetamide, Cu 2 O films with granular morphology are formed. The growth mechanism is proposed according to the experimental results. Due to the aligned 2-D structure, the properties of the optical absorption and the charge carrier transportation for the novel Cu 2 O films are better than that for the Cu 2 O films with granular morphology. So, the films with 2-D aligned nanosheets morphology outperform the granular morphology in achieving higher photoelectrocurrent efficiency under simulated solar light. It makes the 2-D nanosheet structured Cu 2 O films more suitable for solar energy applications. In addition, a facile and efficient method is proposed here toward the preparation of films with novel structure on metal substrates (Cu, Al, Zn, etc.), for which a number of promising applications in various fields can be envisioned.