Fabric imbued with carbon nanotubes capable of powering LEDs
Image credit: rice university
Tiny carbon nanotubes can act as a thermoelectric generator when sewn into fabrics for powering devices, researchers have said.
A team from Rice University in Texas were able to power an LED using heat from the Sun that radiated onto the nanotubes. With further development, they believe that such materials could become building blocks for fibre and textile electronics as well as energy harvesting.
The same nanotube fibres could also be used as heat sinks to actively cool sensitive electronics with high efficiency.
If one side of a thermoelectric material is hotter than the other, it produces energy – this is the concept the researchers used for the project. Until now, other assemblies of nanomaterials have not displayed the necessary “giant power factor” – about 14 milliwatts per meter kelvin squared – that was demonstrated in this carbon nanotube fibre.
“The power factor tells you how much power density you can get out of a material upon certain temperature difference and temperature gradient,” said Natsumi Komatsu (pictured), lead author of the paper.
She added that a material’s power factor is a combined effect from its electrical conductivity and what’s known as the Seebeck coefficient, a measure of its ability to translate thermal differences into electricity.
The team tuned the nanotubes’ inherent Fermi energy, which is a property that determines electrochemical potential, by chemically doping the nanotubes made into fibres.
While the fibres they tested were cut into centimetre lengths, in theory they could be spooled into much longer lengths.
“No matter where you measure them, they have the same very high electrical conductivity,” Komatsu explained. “The piece I measured was small only because my setup isn’t capable of measuring 50 metres of fibre.”
Co-author Matteo Pasquali said: “Carbon nanotube fibres have been on a steady growth path and are proving advantageous in more and more applications.
“Rather than wasting carbon by burning it into carbon dioxide, we can fix it as useful materials that have further environmental benefits in electricity generation and transportation.”
Researchers at Chalmers University of Technology have previously demonstrated a fabric that converts kinetic energy into electric power.
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