New solar cells transform heat into usable energy

Solar cells add another function to an already long-list of beneficial uses – they can transform heat into usable energy, a new study revealed.

We are always on the lookout for more sources of renewable energy: a recently developed solar panel that converts raindrops into electricity, for example. Now, researchers from MIT have come up with a device that will convert heat into energy.

How Does It Work?

The new solar cells have a transitional component that first absorbs all the heat and energy to a temperature that would initiate heat radiation. By altering the configuration and materials of the added layers, the radiation can be emitted via accurate wavelengths of light that the solar cell can gather. This method makes the solar cell perform efficiently while reducing the solar cell heat generation.

The important part of the device is the use of nanophotonic crystals that have the ability to discharge determined wavelengths precisely when the cells are heated.

The method also uses a traditional solar-concentrating system equipped with mirrors that direct the sunlight to keep the high temperature focused. An advanced optical filter then allows all the preferred wavelengths of light to the PV cell (a photovoltaic cell (PV cell) is a specialized semiconductor diode that converts visible light into direct current (DC)), while unnecessary wavelengths were reflected and re-absorbed. The reabsorption of these unwanted wavelengths maintains the photonic crystal's temperature.

Through this operation, the photonic crystal creates emissions via heat instead of light, which means that environmental changes would not affect its efficiency. This way, solar power can be used continuously 24 hours, 7 days a week - no energy goes to waste.

"This is the first time we've actually put something between the sun and the PV cell to prove the efficiency," said Bierman. "We showed that just with our own unoptimized geometry, we in fact could break the Shockley-Queisser limit."

The team is now looking at expanding their research to look for methods to scale up their experimental unit.

Just think.  Now an overheating iPad, or phone or laptop can be convering its heat into power one day.  Perhaps to run the fan to keep it from melting.

Adapted from an article on