Fast and simple deposition of thin film of Cu2-xS nanosheets on copper foil for solar energy harvesting via photo-thermo-electric conversion

Solar energy harvesting using thermoelectric generator (TEG) devices is an overlooked but practical strategy for sustainable power generation. Solar radiation can be converted to electricity by integrating TEGs with solar absorbers. Therefore, developing solar absorbers is crucial to enhance the performance of TEG devices for efficient photo-thermo-electric conversion. Here, we presented a simple and cost-effective method to prepare a stable thin film of copper sulfide nanosheets on a copper plate substrate, taking only a few seconds to complete. This method led to forming a mixture of Cu2-xS nanosheets (x = 0.03, 0.05, and 1) vertically grown on the surface of the copper foil and possessed tightly packed porous clustered structures. The prepared Cu-foil@Cu2-xS nanosheets demonstrated exceptional photothermal characteristics, achieving a temperature of 65 °C within 3–4 min when exposed to the illumination of a lamp with an intensity of 500 W/m2. There was a significant increase in power output compared to bare thermoelectric modules when the Cu-foil@Cu2-xS nanosheets were used as solar absorbers in a solar-thermo-electric generator (STEG) system. The study highlights the potential of Cu2-xS nanosheets as solar absorbers in STEGs.