Starfish-like particles and nanowires interwoven architecture of CuO for water infiltration–induced electrical device

In the face of sustainable energy development, electricity generation using liquid infiltration in small-sized channels has become one of the effective strategies to optimize energy utilization. As p-type semiconductors, CuO nanomaterials exhibit great potential in energy storage and conversion, which can be used as suitable active materials for constructing nanogenerators. In this study, we proposed CuO water infiltration–induced electrical devices based on starfish-like particles and nanowires (NWs) interwoven architecture. Attributed to the ionovoltaic effect, the electrical signal value is reflected by the difference in carrier concentration between wet and dry regions. Notably, we innovatively used the oxidation–reduction–reoxidation method to control the crystal structure of CuO. In addition, we examined the relationship between CuO microstructure and performance and further explored the effect of different reaction conditions on the device output performance. It was demonstrated that a single device (7.5 cm × 2.5 cm × 18.3 µm) can generate an open-circuit voltage (Voc) of 0.67 V and a short-circuit current (Isc) of 2.49 μA at room temperature when 30 μL of 0.1 mol L−1 NaCl solution permeates from one end of the film. Under a 0.5 mol L−1 NaCl condition (seawater concentration), the device can generate a Voc of 0.82 V and an Isc of 2.70 μA, which is expected to be utilized in the field of sensors for identifying the different concentrations of ions.