Australian Thin Film Solar

Australian Thin Film Solar

Dr. Kylie Catchpole
-- http://www.pv.unsw.edu.au/Staff/kyliecatchpole.asp |
-- http://www.iop.org/EJ/journal/-page=featauth/-author=407/0268-1242/1 | interview

Phd student Supriya Pillai
Journal of Applied Physics

The ARC Photovoltaics Centre of Excellence officially came into being on 13th June 2003. The new Centre is charged with the mission of advancing silicon photovoltaic research and applying these advances to the related field of silicon photonics.

Thin-Film
The primary aim of the Centre’s thin-film cell group (or “second-generation group”) is to develop polycrystalline silicon (poly-Si) thin-film solar cells on glass, an approach that is widely recognised as being a pathway towards substantially lowering the cost of photovoltaic (PV) solar electricity.

ARC Photovoltaics Centre of Excellence
-- http://www.pv.unsw.edu.au/research/advancedsilicon.asp | Site Map |

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1st May 2007

New cells to deliver cheaper solar power

Cheaper solar power could be available in a few years due to pioneering work by Australian scientists on an improved solar cell.

Researchers at the

University of New South Wales
ARC Photovoltaics Centre of Excellence

have developed a means of increasing the cell's light-trapping ability by up to 50 per cent.

They say that apart from a home's cooking and hot-water heating needs, such improvement to an electric solar system could power an average house with panels covering 10 square metres.

"Overall, our new solar cells increase power generated by 30 per cent," said Dr Kylie Catchpole, co-author of the study.

As part of the process, UNSW researchers, led by Phd student Supriya Pillai, place a thin film (about 10 nanometres thick) of silver onto a solar cell and heat it to 200 degrees Celsius.

The film breaks into tiny 100-nanometre "islands" of silver and raises its light-trapping efficiency.

With this the team can move from thick expensive silicon "wafers" to cheaper "thin film" cells with less silicon.

"Most thin-film solar cells are between eight and 10 per cent efficient, but the new technique could increase efficiency to between 13 and 15 per cent," Dr Catchpole said.

"If they're below 10 per cent efficient, then you can't really afford to install them, because it would take up too much of your roof area, for example, to power your house."

It can start to become commercially viable once the converting efficiency exceeds 10 per cent.

Silicon is a poor absorber of light.

That affects the cost of solar technology, as up to 45 per cent of its cost is due to the cost of silicon.

Prices for an installed solar system for an average house could fall 25 per cent from $20,000 to $15,000 once the technology filters through, the researchers say.

There are only 30,000 Australian households - out of eight million - which have solar panels for electricity.

If this solar system is used with a solar heating system for water and cooking, the excess power generated can be sent back to the power grid.

"You connect with the electricity grid system where you have no batteries and then sell back your excess electricity," Dr Catchpole said.

"You are then not wasting any electricity, similar to Michael Mobb's house (in Chippendale, Sydney)," she said.

The report of the breakthrough will appear in the upcoming issue of the Journal of Applied Physics.

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Group Leader: Dr Kylie Catchpole

Recent developments in GaAs-based solar cells have led to efficiencies above 30%. Widespread adoption of GaAs-based solar cells for space applications has also brought about large reductions in material costs. However, GaAs cells are still much more expensive than silicon cells. This application addresses the development of a manufacturable technique for lifting off thin films of GaAs. This approach allows a significantly reduced cost due to reduced materials usage, while maintaining high efficiency. Light-trapping for lifted-off cells will also be developed, which will allow the theoretical limit to performance to be approached, and fundamental processes in GaAs to be investigated.

http://www.pv.unsw.edu.au/research/thinfilm.asp