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,
Pressofficer: Sofie Hebrand; Tel:+4631-772 84 64; Fax:+4631-772 59 44; email@example.com
Sofie Hebrand | idw
Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts
08.12.2016 | Institut für Solarenergieforschung GmbH
Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine