Efficient solar cells coming soon

20:36, Jan 18 2013
NOVEL IDEA: Dr Justin Hodgkiss, a nanotechnologist, is using lasers to research ways of making cheap solar cells.

Revolutionary nanotechnology allowing householders to harness enough energy from the sun's rays to free them from mounting electricity bills is just around the corner.

Wellington scientist Justin Hodgkiss is at the forefront of the global race to develop commercially viable printable energy- generating solar cells. The cells could transform life in the Third World and free the First World from the costly shackles of the electricity grid.

The 34-year-old's work with lasers is part of a global push to revolutionise "personalised energy" by refining polymer sheets of solar cells to the point where they are as cheap as house paint or glass.

"You'll essentially be able to buy X number of metres from a roll at Bunnings and plug it into electrical sockets," the Rotorua-born MIT and Cambridge University scholar says.

The technology is likely to take consumers off-grid and could one day blanket neglected areas of light-absorbing idle space - such as the roofs of large buildings or unused areas around motorways.

Current solar cell technology is made from silicon - the precious chemical metalloid used in computer and electronics manufacturing that is costly to process into solar cell technology.


"It's a novel idea to have solar cells made from cheap materials like plastic."

Solar is probably the one renewable energy that can be used "at scale" around the world.

Dr Hodgkiss likens the state of the electricity grid to the telecommunications network 20 years ago when the landline dominated.

Since then, mobile phones have transformed the telco universe, creating a prepaid market allowing customers to go "off- grid" by not having to buy into fixed contracts.

"We could be freed from the electricity grid in the same way - in Third World countries they've skipped the landlines and that's where the big impact for solar energy will be."

Developing countries don't have "legacy" grids so electrifying a city or village can have a significant impact.

British firm Eight19 is already bringing pay-as-you-go solar cell technology to Kenyans, using mobile phones as the electronic middleman.

The firm provides cellphones and solar cells, which can be unlocked by buying a weekly scratch credit card.

The cards have a code that gets keyed into a control box, which then charges a battery pumping out electricity for lighting or cellphone charging.

"It's cheaper than the alternatives, like kerosene, and gives them electricity and they don't have to outlay on the solar cell," Dr Hodgkiss says.

After a year or so, consumers have paid enough in scratch-card credit to own the product outright and any extra money that would have gone to paying for fuel like kerosene or candles is banked by users, eventually allowing them to power more devices.


Justin Hodgkiss says the basic science allowing cheap, effective solar cells to go to the mass market will be ready in a decade.

After that it becomes a "manufacturing or engineering problem and will ultimately be judged by the marketplace".

As the Rutherford Discovery Fellowship winner and principal investigator for the MacDiarmid Institute for Advanced Material and Nanotechnology, he will continue his research to find out more about the physics of polymer light absorption in solar cells.

"It's about how solar cells take light and spit it back out as electricity and how that process can be improved."

Inside their ultra-fast laser lab at Victoria University, he and his team are working to solve the photocurrent puzzle, but there's one major obstacle: Pivotal processes involve timescales ranging from seconds down to one millionth of one billionth of a second - known as a femtosecond.

"The femtosecond scale is so crucial because it's at that timescale when the material that's quickly absorbing light decides whether to create electricity or heat and we want to create electricity."

The laser light experiments are like strobe photography but have a billion-fold improved time resolution, Mr Hodgkiss says.

"We're getting lasers to answer questions that have relevance to problems in the real world."

The Dominion Post