Nanophotonic material shows thermoelectric capabilities

Developed by a University of Michigan-led team of chemical and materials science engineers, the material controls the flow of infrared radiation and is stable at temperatures of 2,000^oF in air, which is said to be a nearly twofold improvement over existing approaches.

The material uses destructive interference to reflect infrared energy while letting shorter wavelengths pass through. This could potentially reduce heat waste in thermophotovoltaic cells, which convert heat into electricity but cannot use infrared energy, by reflecting infrared waves back into the system. The material could also be useful in optical photovoltaics, thermal imaging, environmental barrier coatings, sensing, camouflage from infrared surveillance devices and other applications.

"It's similar to the way butterfly wings use wave interference to get their colour. Butterfly wings are made up of colourless materials, but those materials are structured and patterned in a way that absorbs some wavelengths of white light but reflects others, producing the appearance of colour," said Andrej Lenert, U-M assistant professor of chemical engineering and co-corresponding author of the study in Nature Nanotechnology. "This material does something similar with infrared energy. The challenging part has been preventing breakdown of that colour-producing structure under high heat."