Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Evolution Inspires More Efficient Solar Cell Design

28.01.2013
Geometric pattern maximizes time light is trapped in solar cell
The sun’s energy is virtually limitless, but harnessing its electricity with today’s single-crystal silicon solar cells is extremely expensive — 10 times pricier than coal, according to some estimates. Organic solar cells — polymer solar cells that use organic materials to absorb light and convert it into electricity — could be a solution, but current designs suffer because polymers have less-than-optimal electrical properties.

Researchers at Northwestern University have now developed a new design for organic solar cells that could lead to more efficient, less expensive solar power. Instead of attempting to increase efficiency by altering the thickness of the solar cell’s polymer layer — a tactic that has preciously garnered mixed results — the researchers sought to design the geometric pattern of the scattering layer to maximize the amount of time light remained trapped within the cell.

Using a mathematical search algorithm based on natural evolution, the researchers pinpointed a specific geometrical pattern that is optimal for capturing and holding light in thin-cell organic solar cells.

The resulting design exhibited a three-fold increase over the Yablonovitch Limit, a thermodynamic limit developed in the 1980s that statistically describes how long a photon can be trapped in a semiconductor.

A paper about the results, “Highly Efficient Light-Trapping Structure Design Inspired by Natural Evolution,” was published January 3 in Scientific Reports, a publication of Nature.

In the newly designed organic solar cell, light first enters a 100-nanometer-thick “scattering layer,” a geometrically-patterned dielectric layer designed to maximize the amount of light transmitted into the cell. The light is then transmitted to the active layer, where it is converted into electricity.
“We wanted to determine the geometry for the scattering layer that would give us optimal performance,” said Cheng Sun, assistant professor of mechanical engineering in Northwestern’s McCormick School of Engineering and Applied Science and co-author of the paper. “But with so many possibilities, it’s difficult to know where to start, so we looked to laws of natural selection to guide us.”

The researchers employed a genetic algorithm, a search process that mimics the process of natural evolution, explained Wei Chen, Wilson-Cook Professor in Engineering Design and professor of mechanical engineering at McCormick and co-investigator of the research.

“Due to the highly nonlinear and irregular behavior of the system, you must use an intelligent approach to find the optimal solution,” Chen said. “Our approach is based on the biologically evolutionary process of survival of the fittest.”

The researchers began with dozens of random design elements, then “mated” and analyzed their offspring to determine their particular light-trapping performance. This process was carried out over more than 20 generations and also accounted for evolutionary principles of crossover and genetic mutation.

The resulting pattern will be fabricated with partners at Argonne National Laboratory.

Also co-authoring the paper were co-lead authors Chen Wang and Shuangcheng Yu, graduate students in McCormick’s Department of Mechanical Engineering.

Megan Fellman | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Power and Electrical Engineering:

nachricht Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>