Researchers from Nanjing University in China have developed a new device of 3D hollow-cone structure based on a graphene oxide film that can greatly increase the solar-thermal conversion efficiency.
The device, named 'Artificial Transpiration', is inspired by the transpiration process of trees. It has a special 1D water path within it, which can reduce the energy loss in conduction. The cone structure can reportedly collect more sunlight throughout the day when compared to a flat device, as about 10-50% of sunlight is diffusive. Thus it performs even better in the real world than in the laboratory, the team said.
As a result, the device can enhance the solar-thermal conversion rate to 85%, which is much higher than the 40% rate of common devices, the researchers said.
The team first applied this structure to solar waste-water treatment, and tests showed that it could not only retrieve clean water but also recycle heavy metals such as copper and cadmium.
In the future, the team will aim to further optimize the structure to have a longer life and recycle more heavy metals.