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Nanomaterial to help turn heat into electricity Physicists have demonstrated a new artificial material, or metamaterial, that glows in an unusual way when heated. Š Stock.Adobe.com/au/mara_lingstad

The findings could drive a revolution in the development of cells that convert radiated heat into electricity, known as thermophotovoltaic cells. Thermophotovoltaic cells have been predicted to be more than twice as efficient as conventional solar cells. They do not need direct sunlight to generate electricity; instead, they can harvest heat from their

with a thermophotovoltaic cell. The key to

The efficiency of thermophotovoltaic

surroundings in the form of infrared

the metamaterial’s remarkable behaviour

cells based on the metamaterial can be

radiation. They can also be combined with

is its novel physical property, known as

further improved if the emitter and the

a burner to produce on-demand power or

magnetic hyperbolic dispersion. Dispersion

receiver have just a nanoscopic gap

can recycle heat radiated by hot engines.

describes the interactions of light with

between them. In this configuration,

The metamaterial, made of tiny

materials and can be visualised as a 3D

radiative heat transfer between them

nanoscopic structures of gold and

surface representing how electromagnetic

can be more than 10 times more efficient

magnesium fluoride, radiates heat in

radiation propagates in different directions.

than between conventional materials. The

specific directions. The geometry of

For natural materials, such as glass

metamaterial was created by researchers

the material can be tweaked to give off

or crystals, the dispersion surfaces have

from the Australian National University,

radiation in specific spectral range, in

simple forms: spherical or ellipsoidal. The

the ARC Centre for Ultrahigh bandwidth

contrast to standard materials that emit

dispersion of the new metamaterial is

Devices for Optical Systems and the

their heat in all directions as a broad

hyperbolic in form. This arises from the

University of California, Berkeley. Their

range of infrared wavelengths. This makes

material’s remarkably strong interactions

work has been published in the journal

it suitable for use as an emitter paired

with the magnetic component of light.

Nature Communications.

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Jun/Jul 2016 - Sustainability Matters 33

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Sustainability Matters Jun/Jul 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...

Sustainability Matters Jun/Jul 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...