Graphene Solar Thermal Film Could Be a New Way to Harvest Renewable Energy

Illustration: Swinburne University Researchers at the Center for Translational Atomaterials (CTAM) at Swinburne University of Technology in Melbourne, Australia, have developed a new graphene-based film that can absorb sunlight with an efficiency of over 90 percent, while simultaneously eliminating most IR thermal emission loss—the first time such a feat has been reported. The result is an efficient solar heating metamaterial that can heat up rapidly to 83 degrees C (181 degrees F) in an open environment with minimal heat loss. Proposed applications for the film include thermal energy harvesting and storage, thermoelectricity generation, and seawater desalination. Suppressing thermal emission loss—also known as blackbody radiation—while simultaneously absorbing solar light is critical for an efficient solar thermal absorber but is extremely challenging to achieve, says Baohua Jia , founding director of CTAM. “That’s because, depending on the absorbed heat and properties of the absorber, the emission temperature differs, which leads to significant differences in its wavelength,” she explains. “But we’ve developed a three-dimensional structured graphene metamaterial (SGM) that is highly absorbent and selectively filters out blackbody radiation.” The 3D SGM is composed of a 30-nanometer-thick film of alternating graphene and dielectric layers deposited on a trench-like nanostructure that does double duty […]

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