Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Energetic nanoparticles swing sunlight into electricity

21.02.2008
The electrons in nanoparticles of noble metal oscillate together apace with the frequency of the light. This phenomenon can be exploited to produce better and cheaper solar cells, scientists at Chalmers University of Technology in Sweden have shown.

Electricity-generating solar cells are one of the most attractive alternatives for creating a long-term sustainable energy system, but thus far solar cells have not been able to compete economically with fossil fuels. Researchers are now looking at how nanotechnology can contribute in bringing down the cost.

Solar cells are constructed of layers that absorb sunlight and convert it to electrical current. Thinner solar cells can yield both cheaper and more plentiful electricity than today's cells, if their capacity to absorb sunlight is optimized.

One way to enhance the absorption of the solar harvesting material in a solar cell is to make use of nanoparticles of noble metal. Carl Hägglund at Chalmers has looked at how this can be done in his recently completed doctoral dissertation.

The particles involved have special optical properties owing to the fact that their electrons oscillate back and forth together at the same rate as the frequency of the light, that is, the color of the light. The particles catch the light as tiny antennas and via the oscillations the energy is passed on as electricity. These oscillations, plasmons, are very forceful at certain so-called plasmon resonance frequencies, which in turn are influenced by the form, size, and surroundings of the particles.

"What we've done is to make use of nanotechnology to produce the particles and we've therefore been able to determine the properties and see how they can enhance the absorption of light of different colors,"

says Carl Hägglund.

In the context of solar cells, the great challenge is to efficiently convert the energy that is absorbed in the electron oscillation to energy in the form of electricity.

"We show that it is precisely the oscillations of the particles that yield the energy, how it is transmitted to the material and becomes electricity. It might have turned out, for example, that the oscillations simply generated heat instead," says Carl Hägglund.

The efficiency of the best solar cells today is already very high. The possibility of achieving even better solar cells therefore lies in using less material and in lowering production costs.

With solar cells of specially designed nanoparticles of gold, which is what Carl Hägglund has looked at, a layer only a few nanometers thick is required for the particles to be able to absorb light in an efficient way.

The dissertation examines the effect of nanoparticles of noble metal on two different types of solar cells, which can be said to represent two extremes. In one type of solar cell the light is absorbed in molecules on a surface, and in the other type deep inside the material.

The experimental and theoretical results show that the particles can help transmit the light's energy to useful electricity in several different ways and that it's possible to enhance the absorption of solar cells both on the surface and deep inside via different mechanisms.

This work has been carried out within the framework of a materials science research program (PhotoNano) funded by the Swedish Foundation for Strategic Research.

For more information, please contact: Carl Hägglund, Chemical Physics, Department of Applied Physics, Chalmers University of Technology,
phone: +46 (0)31-772 33 76; cell phone: +46 (0)738-154696.
carl.hagglund@chalmers.se
Supervisor: Professor Bengt Kasemo, Chemical Physics, Department of Applied Physics, Chalmers University of Technology, phone: +46 (0)31 772 33 70; cell phone: +46 (0)708-28 26 01 kasemo@fy.chalmers.se

Pressofficer: Sofie Hebrand; Tel:+4631-772 84 64; Fax:+4631-772 59 44; sofie.hebrand@chalmers.se

Sofie Hebrand | idw
Further information:
http://chalmersnyheter.chalmers.se/chalmers03/english/Article.jsp?article=11030
http://publications.lib.chalmers.se/cpl/record/index.xsql?pubid=67239

More articles from Power and Electrical Engineering:

nachricht Six-legged robots faster than nature-inspired gait
17.02.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Did you know that IR heat plays a central role in the production of chocolates?
14.02.2017 | Heraeus Noblelight GmbH

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>