Wednesday 28 November 2007

Solar technology to dye for

By Claire Gorman

As the urgency of addressing global warming increases, so does the race to find a cheap method of collecting 'clean' energy.

While you've certainly heard of some methods of gathering solar energy - like solar thermal and silicon cells - others are less well known.

One local business has honed a solar technology based on photosynthesis and nanotechnology.

This type of solar cell was first created in 1991. However, Queanbeyan company Dyesol has perfected a technique for making the components and is now a world leader in the field.

Dyesol does not actually sell solar panels but instead creates the components, most of which are exported overseas.

666 ABC Canberra's environment reporter, Claire Gorman, met up with managing director Sylvia Tulloch in a lab full of test tubes and glass vessels.

"In photosynthesis chlorophyll is absorbing all the energy in the red part of the spectrum and reflecting the blue and the yellow, so a leaf looks green.

"Our solar technology mimics photosynthesis, so we use a dye to capture the energy," Sylvia explained.

"This dye is not easy to synthesise and it is not easy to purify with good yields," she said.

Sylvia said while the dye had been modified, it came from the same family of dyes used for archival photographs because these lasted a long time.

"We need our solar panels to last for decades," she said.

The second ingredient in the solar panels a nanoparticulate paste - a creamy substance with titanium dioxide nanoparticles in it - which is screen printed onto glass and then baked.

On the topic of nanoparticles, Sylvia said they were not as mysterious as they might sound.

"It's really just limiting the growth of the crystals before they grow too big," she said.

This component is then dyed and put in a sandwich with glass on either side to let the light in and a liquid electrolyte which acts like a battery.

"It's normal glass but it has a conductive coating on it because an important thing in a solar panel is to have a conductor so you can capture the electrons and then send them to the circuit," she said.

"In a solar panel a cells is only about half a volt and that is a very low voltage, so you need to build up a number of cells to give you a useful voltage."

The next step for Dyesol, Sylvia said, was turning metal into solar cells so that rooves and fences could generate energy too.