Nanowire solar cells raise efficiency limit

March 24, 2013, University of Copenhagen
Nanowire crystals are used as the solar cells. The image (left) shows a SEM (Scaning Electron Microscope) image of GaAs nanowire crystal grown on a Silicon substrate. A TEM (Transmission Electron Microscope) image (middle) shows a single nanowire. Further zooming in on the crystal structure, using STEM (Scanning Transmission Electron Microscope) imaging, shows the actual atomic columns (right). Credit: Niels Bohr Institute

Scientists from the Nano-Science Center at the Niels Bohr Institut, Denmark and the Ecole Polytechnique Fédérale de Lausanne, Switzerland, have shown that a single nanowire can concentrate the sunlight up to 15 times of the normal sun light intensity. The results are surprising and the potential for developing a new type of highly efficient solar cells is great.

Due to some unique physical properties of nanowires, the limit of how much energy we can utilize from the sun's rays is higher than previous believed. These results demonstrate the great potential of development of nanowire-based , says PhD Peter Krogstrup on the surprising discovery that is described in the journal Nature Photonics.

The research groups have during recent years studied how to develop and improve the quality of the nanowire crystals, which is a cylindrical structure with a diameter of about 10,000 part of a human hair. The nanowires are predicted to have great potential in the development not only of solar cells, but also of future quantum computers and other electronic products.

The figure shows that the sun's rays are drawn into a nanowire, which stands on a substrate. At a given wavelength the sunlight is concentrated up to 15 times. Consequently, there is great potential in using nanowires in the development of future solar cells. Credit: Niels Bohr Institute

It turns out that the nanowires naturally concentrate the sun's rays into a very small area in the crystal by up to a factor 15. Because the diameter of a nanowire crystal is smaller than the wavelength of the light coming from the sun it can cause resonances in the intensity of light in and around nanowires. Thus, the resonances can give a concentrated sunlight, where the energy is converted, which can be used to give a higher conversion effeciency of the sun's energy, says Peter Krogstrup, who with this discovery contributes to that the research in based on nanowires get a real boost.

New efficiency limit

The typical efficiency limit - the so-called "Shockley-Queisser Limit" - is a limit, which for many years has been a landmark for solar cells efficiency among researchers, but now it seems that it may be increased.

It's exciting as a researcher to move the theoretical limits, as we know. Although it does not sound like much, that the limit is moved by only a few percent, it will have a major impact on the development of solar cells, exploitation of nanowire solar rays and perhaps the extraction of energy at international level. However, it will take some years years before production of solar cells consisting of nanowires becomes a reality, says Peter Krogstrup who just completed his PhD at the Niels Bohr Institute, University of Copenhagen.

The research is conducted in collaboration with the Laboratory des Matériaux Semiconducteurs, Ecole Polytechnique Fédérale de Lausanne, the Foundation and the company SunFlake A / S. Their scientific findings work support results published in the journal Science in January. Here, a group of researchers from Lund, showed that the sun's rays was sucked into the due to the high amount of power that their solar cell produced.

Explore further: Major advance in understanding how nanowires form

Related Stories

Major advance in understanding how nanowires form

March 25, 2011

New insights into why and how nanowires take the form they do will have profound implications for the development of future electronic components. PhD student Peter Krogstrup from the Nano-Science Center at the Niels Bohr ...

Great potential with new ultra-clean nanowires

November 9, 2010

New ultra-clean nanowires produced at the Nano-Science Center, University of Copenhagen will have a central role in the development of new high-efficiency solar cells and electronics on a nanometer scale. PhD student Peter ...

Danish nanowires have great potential

November 2, 2009

Danish nanophysicists have developed a new method for manufacturing the cornerstone of nanotechnology research - nanowires. The discovery has great potential for the development of nanoelectronics and highly efficient solar ...

Solar cells of the future

December 18, 2007

A new material, nano flakes, may revolutionise the transformation of solar energy to electricity. If so, even ordinary households can benefit from solar electricity and save money in the future.

Nano-tuned solar cells

May 18, 2011

Solar cells that are more effective and cost less in production: Within the EU-project N2P (Nano to Product) researchers developed nano tuned surfaces to gain both.

Recommended for you

Sculpting stable structures in pure liquids

February 21, 2019

Oscillating flow and light pulses can be used to create reconfigurable architecture in liquid crystals. Materials scientists can carefully engineer concerted microfluidic flows and localized optothermal fields to achieve ...

How to freeze heat conduction

February 21, 2019

Physicists have discovered a new effect, which makes it possible to create excellent thermal insulators which conduct electricity. Such materials can be used to convert waste heat into electrical energy.

Water is more homogeneous than expected

February 21, 2019

In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases, even under ambient conditions. However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss ...

Correlated nucleons may solve 35-year-old mystery

February 20, 2019

A careful re-analysis of data taken at the Department of Energy's Thomas Jefferson National Accelerator Facility has revealed a possible link between correlated protons and neutrons in the nucleus and a 35-year-old mystery. ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1.2 / 5 (5) Mar 24, 2013
This is excellent news. With luck and government support, solar power and other alternatives should begin to displace the stranglehold of coal and oil.
3.7 / 5 (3) Mar 24, 2013
So what is their new efficiency record?
3 / 5 (2) Mar 24, 2013
Ho hum...
5 / 5 (3) Mar 24, 2013
Shockley Queisser puts the limit for single band gap cells at 41 percent. (Multi-bandgap cells can have more than that).

What they have shown here is that even single bandgap cells can be better than previously thought - which is big, because manufacturing a single bandgap cell is much easier than multi-bandgap cells.
3 / 5 (8) Mar 24, 2013
This is excellent news. With luck and government support, solar power and other alternatives should begin to displace the stranglehold of coal and oil.

No government support please. Every time governments get involved in the energy industry, energy gets more expensive, just look at the cost of a barrel of oil coming from the middle east, $100/barrel all because those governments run the business over there. The world is awash in oil yet the price remains little changed because governments like to manipulate much of our daily lives to the benefit of the political class.
5 / 5 (1) Mar 25, 2013
Increasing that number would appear to be the entire justification for the research.

"So what is their new efficiency record?" - JRI

and yet the article doesn't provide it.

Thus the author of the article doesn't comprehend the basic reason for the research.

Dumber than dirt.
1 / 5 (1) Mar 25, 2013
It would be nice to see what they are thinking the new numbers are, I would agree VendicarE. Anyone know what type of solar cells they would apply to? What do they mean by
"However, it will take some years years before production of solar cells consisting of nano wires becomes a reality" That could mean 3,6,10 or am I just asking too much. Does this change the linear progression curve of development into an asymptotic curve? Let's explore all workable energy solutions!
not rated yet Mar 25, 2013
Apparently this was shown back in 2006 and there are 11 patents on it.They increase the solar cell efficiency by up to 18% but weather this is an additional percentage increase or a percentage of the current efficiency i can not tell. Here is the blog from 2006 highlighted by a guy called Bob Crowley in a duplicate of this article in (rdmag . com)
microphonium . blogspot . ie/search?q=solar

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.