MIT tech to greatly improve solar energy efficiency

21 Jan 2014

A nanophotonic solar thermophotovoltaic device. Photo by John Freidah

Massachusetts Institute of Technology (MIT) researchers have created a device it hopes will vastly improve the efficiency of solar-energy harvesting that uses a series of super-conductive nanotubes.

In an article on its news website, graduate student Andrej Lenert, associate professor of mechanical engineering Evelyn Wang, physics professor Marin Soljačić, principal research scientist Ivan Celanović, and three others have made the breakthrough, which will aim to use sunlight to heat a high-temperature material whose infrared radiation would then be collected by a conventional photovoltaic cell.

When the material heats up when sunlight is concentrated on it, it will produce an intense amount of heat signified by a red glow that subsequently releases light of a particular wavelength, harnessing more energy than before.

Huge potential

By collecting the sun’s rays through the photovoltaic cell, the MIT team hopes to one day increase solar energy harvesting to reach 20pc efficiency once the technology reaches a grander scale and additional filters are in place.

Currently the experiment has reached 3.2pc increased efficiency through absorption in the multi-walled carbon nanotubes.

The team has been able to concentrate sunlight to a factor of 750 times more than its normal levels, which then heated the absorber-emitter to a temperature of 962°C. 

This is a breakthrough in the field, as previous tests on a similar concept could only reach an efficiency level maximum of 1pc.

The team wrote about the innovative material in a journal launched this week entitled Nature Nanotechnology and hopes to develop the technology further in the coming months and years.

Colm Gorey was a senior journalist with Silicon Republic