Making the most of low-grade silicon for cheaper, more efficient solar panels


May 7, 2013

Research at UNSW increases the conversion efficiency of solar cells made using lower-cost, low-grade silicon (Photo: Shutterstock)

Research at UNSW increases the conversion efficiency of solar cells made using lower-cost, low-grade silicon (Photo: Shutterstock)

While we wait for affordable multi-junction solar cells that are pushing past the 40 percent conversion efficiency mark to make it out of the lab and onto our roofs, we have to make do with standard commercial silicon cells that currently max out at around 19 percent. A team from the University of New South Wales (UNSW) in Australia has found a way to improve the quality of low-grade silicon, enabling higher efficiency solar cells to be produced from cheaper, low-grade silicon.

It’s been known for several decades that hydrogen atoms can be introduced to help correct the efficiency-reducing defects and contaminants found in lower-grade silicon. However, researchers have had limited success in controlling the hydrogen to maximize its benefits. The solution found by the UNSW team relates to controlling the charge state of the hydrogen atoms.

Hydrogen atoms can exist in a positive, negative or neutral charge state, which determines how well they can move around the silicon and their reactivity, which is important to help correct the defects. The researchers say that by controlling the charge state, it will be possible to achieve higher efficiencies using lower-cost, low-grade silicon.

“We have seen a 10,000 times improvement in the mobility of the hydrogen and we can control the hydrogen so it chemically bonds to things like defects and contaminants, making these inactive,” says Scientia Professor Stuart Wenham from the School of Photovoltaics and Renewable Energy Engineering at UNSW. “This process will allow lower-quality silicon to outperform solar cells made from better-quality materials.”

Wenham expects to achieve efficiencies of between 21 and 23 percent using this new technique, which was patented by the UNSW team earlier this year. The researchers have attracted the interest of industry partners interested in commercializing the technology, and they are working with manufacturing equipment companies to introduce it into solar cell manufacturing processes.

Source: UNSW

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Solar efficiency improves when the distance the electricity has to travel is only from the roof of your house to your need rather than from a solar farm with a drop of energy every foot it travels. Dump the grid, we will tear it down so be prepared. The new hybrid is solar compressed air, and it will work on your car, and the once rich oil Barons can panhandle till they die, bastards all of them, enemies of us and our home Planet Earth. Got sulfur?

Patrick McGean

This can be more important than developing an expensive PVC that gets very high efficiency, since what really matters in bringing PVC into popular acceptance is cost per watt, not watts per square foot. Of course, this is the installation cost, which does depend on size.

David Leithauser

This article, same source, from 2009 claimed it had achieved 41% production. This link is also in the article above.

Art Toegemann
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