Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Photonics: Better solar cells around the corner

05.09.2011
Design optimization could help maximize the power conversion efficiency of thin-film silicon solar cells

Silicon is readily available, easy to process, highly stable and non-toxic. It is also one of the best materials for making solar cells. The high quality and purity of silicon needed for fabricating the most efficient silicon-based solar cells, however, has made it difficult to lower production costs for this renewable energy technology.

One approach that could reduce costs is to use a microscopically thin film of silicon with a textured surface to enhance light absorption. Navab Singh at the A*STAR Institute of Microelectronics and co-workers have now highlighted several key factors affecting the power conversion efficiency of surface-textured thin-film solar cells and come up with a ‘nanopillar’ design that maximizes light absorption and minimizes production costs.

The best performing thin-film silicon solar cells at present have efficiencies that are about half that of conventional bulk silicon solar cells. “By investigating a variety of appropriate vertical nanopillar designs we can enhance the light-trapping and -collection efficiency of thin films to compensate for the efficiency loss caused by reduced material quality and quantity,” says Singh.

The researchers investigated various factors that might affect the performance of a thin-film solar cell. These factors include the diameter and length of the nanopillar, as well as the spacing between nanopillars (see image). Similarly important is the design of the positively and negatively charged layers in the solar cells that are needed to separate the electrical carriers created by the absorbed light.

The researchers’ simulations showed that the thickness of the negatively charged layer on the outer side of the pillars should be as thin as possible in order to reduce ‘parasitic’ absorption—the annihilation of light-generated carriers before they cross the junction between layers where they would contribute to electrical power generation. They also found that an axial junction design in which the junction between positive and negative layers is confined to the very top of the pillars leads to a higher open-circuit voltage compared with more conventional radial junction structures in which the negative layer wraps around the entire pillars. Yet they found the converse to be true for the open-circuit current.

Singh and his co-workers therefore show that a balance of these factors is needed in order to optimize designs for light-to-power conversion efficiency in surface-textured thin-film structures, which could eventually lead to thin-film silicon solar cells that are able to match the efficiency of the more expensive single-crystalline silicon solar cells.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics

References
Wong, S. M. et al. Nanopillar array surface-textured thin-film solar cell with radial p-n junction. IEEE Electron Device Letters 32, 176–178 (2011).

Lee Swee Heng | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6382
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht Only an atom thick: Physicists succeed in measuring mechanical properties of 2D monolayer materials
17.01.2018 | Universität des Saarlandes

nachricht Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

Uncovering decades of questionable investments

18.01.2018 | Business and Finance

Novel chip-based gene expression tool analyzes RNA quickly and accurately

18.01.2018 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>