The University of Newcastle, Australia

Something new under the sun

The idea of a photovoltaic paint seemed like pure science fiction when Professor Paul Dastoor began investigating alternative solar energy technology 15 years ago.

Yet the physicist is now on the threshold of bringing to fruition a commercial-scale energy system based on solar cells that can be printed, and ultimately painted, onto surfaces.

Dastoor began experimenting with a class of plastics known as semiconducting polymers in the mid 1990s. While most polymers are electrical insulators, the conductive properties of this group of materials posed the prospect that they could be used in electronic devices such as photo-voltaics.

"Traditional silicon cell solar technology was very expensive then, and still is now, so the idea was to develop an alternative material that would be more cost-effective," Dastoor explains.

"I had read papers about semiconducting polymers and thought, naively, 'How hard can it be to build a polymer solar cell?'

"The answer: bloody difficult! Working out how to handle these materials and make them perform the way we wanted them to was a steep learning curve."

By breaking the semiconducting materials down to tiny particles, Dastoor developed a method of suspending them in water, which led to the concept of producing a solar paint or ink that could be applied to surfaces, such as plastic.

Dastoor then moved to the stage of fabricating solar cells onto a substrate, or base. The first rudimentary prototypes measured just two millimetres by two millimetres and could be produced with a common inkjet printer.

Now, a project that Dastoor started with one vacation student, hosts a team of 25 researchers and was the catalyst for the formation of the Centre for Organic Electronics, the field of study into conductive polymers.

The next step in Dastoor's solar paint research is building a customised printing machine capable of coating solar paint onto hundreds of metres of plastic sheeting. This plastic sheeting could be installed onto roofs of residential houses then wired to inverter boxes to produce electricity in the same way that conventional silicon solar panels operate.

"Our research indicates that a roll of this sheeting on a typical-sized roof of about 150 square metres will provide enough electricity for an average household," Dastoor says.

"However, the installation cost could be approximately one-tenth of installing a silicon solar system that produces the same amount of electricity."

Dastoor likens the basic construction of the solar sheeting - a metal coating on a plastic substrate with coloured ink printed on it - to that of a simple chip packet.

"And we make chip packets so cheaply that we throw them away when we are finished with them," he says, "which gives you an indication of how inexpensively we could manufacture this product."

Coating the solar cells onto plastic sheeting is the first step in realising the technology. Dastoor believes ultimately it will be possible to paint the conductive liquid directly onto a roof or wall, or even apply it as a window tint.

The new large-scale printing facility, funded by a $1 million grant from the Australian National Fabrication Facility, will begin operating later this year at the Newcastle Institute of Energy and Resources (NIER) site on the University campus and Dastoor is seeking $15 million investment to turn the promising lab results into a commercially viable product within three years.

The solar project will also benefit from collaboration between the Centre for Organic Electronics, of which Dastoor is the director, and the CSIRO Energy Centre in Newcastle. The two entities have joined forces to establish a joint Research Centre for Organic Photovoltaics.

"One of the many exciting things about this technology is that it opens up the prospect of a new industry for Newcastle," Dastoor says.

"We sit at the head of the largest coal export port on the planet and yet we know we are not going to be able to mine this coal forever.

"What we are offering is low-cost, environmentally sustainable technology, being developed right here in this University, that could help this region and Australia make the transition to a more diverse, progressive economy."

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