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MIT researchers develop all-carbon solar cell

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June 25, 2012

An atomic-force microscope image of a layer of single-walled carbon nanotubes deposited on...

An atomic-force microscope image of a layer of single-walled carbon nanotubes deposited on a silicon surface, which is the first step in manufacturing the new solar cell

Researchers at MIT have developed a new type of photovoltaic cell made with carbon nanotubes that captures solar energy in the near-infrared region of the spectrum, which conventional silicon solar cells don’t. The new design means solar cell efficiency could be greatly increased, boosting the chances to make solar power a more popular source of energy.

The new solar cell developed at MIT is a consequence of recent advances in the large-scale production of carbon nanotubes. It also features another type of carbon, a fullerene known as C60 (aka Buckminsterfullerene). The nanotubes have to be very pure, single-walled and of the same symmetrical configuration. The material is transparent to visible light and has to be overlaid on conventional silicon cells to form a hybrid cell that could, in theory, capture most of the energy contained in the sunlight it captures.

This is not the first time researchers have used carbon nanotubes to make solar cells, but researcher Michael Strano and his team found that the new all-carbon cells appear to be stable in air, therefore they did not require a layer of polymer to hold the nanotubes together in position. This characteristic eliminates a stage in the production process that hitherto has made it more complex. The cells require relatively small amounts of highly purified carbon, resulting in a lighter end product.

There are several bright, optimistic spots in this research, the scientists say. Although the proof of concept devices have so far achieved an efficiency of only 0.1 percent, the researchers have already identified some of the sources of inefficiency. For instance, they have noticed that homogenous mixtures of carbon nanotubes are more efficient than heterogeneous ones. Mixing single-walled and multiwalled nanotubes is not a good idea, either.

The scientists are positive they are bound to make high-efficiency near-infrared solar cells, and point out that even a low-efficiency cell that works in that region, capturing energy that current cells waste, would be worthwhile provided costs are low. They are now looking into ways to better control the shape and thickness of the layers of the material.

A paper written by Professor Strano describing the all-carbon solar cell in detail was recently published in the journal Advanced Materials.

Source: MIT

About the Author
Antonio Pasolini Brazilian-Italian Antonio Pasolini graduated in journalism in Brazil before heading out to London for an MA in film and television studies. He fell in love with the city and spent 13 years there as a film reviewer before settling back in Brazil. Antonio's passion for green issues - and the outdoors - eventually got the best of him and since 2007 he's been writing about alternative energy, sustainability and new technology.   All articles by Antonio Pasolini
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2 Comments

Almost every edition sees a new concept in solar cells and has done for years but nothing seems to have trickled down to consumers offerings by installers.

The same number of panels seem to be required as before.

In my part of the world if you do not buy a system of more than adequate capacity for your needs the balance that you have to draw from the grid is charged at a hefty penalty over normal rates.

You do not see that mentioned in the ads by people selling 1.5 Kw systems at "bargain prices"

Facebook User
26th June, 2012 @ 06:17 pm PDT

Now if they could only make a solar cell that worked on the ultraviolet light spectrum (full power on a cloudy day).

Billy Brooks
26th June, 2012 @ 11:59 pm PDT
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