Researchers have created a solar-absorbing, ultrathin graphene film with unique properties. The thin film is helpful for solar thermal energy harvesting.
The 90 nm thick material can rapidly heat to 160 °C when exposed to natural sunlight in an open environment. The material property paves the way for new thermophotovoltaics (the direct conversion of heat to electricity): solar seawater desalination systems, infrared light sources and heaters, modulators and interconnects for communication devices, photodetectors, color displays, and even ‘invisible cloaking technology’ by developing large-scale thin films enclosing the objects (to be hidden).
The 2.5 cm x 5 cm working prototype demonstrates the photothermal performance of the graphene-based metamaterial absorber. The researchers have also proposed a low-cost fabrication strategy for the graphene film.
In this study, the reduced graphene oxide layer and grating structures were coated with a solution and fabricated using a laser nanofabrication method, both of which are scalable and low in cost. Because of its fabrication on a flexible substrate and the robustness derived from graphene, it is suitable for industrial use. The physical effect causing such exceptional absorption in such a thin layer is quite general, opening up a wide range of exciting applications. The researchers have developed a new class of optical material with properties that have multiple uses.