Ted Sargent and his team describe their discovery — the world’s first plastic solar cell able to absorb infrared light — in the February issue of the prestigious industry journal Nature Materials.

Their little sample could bring about a sea change in the energy industry, perhaps making solar energy so cheap that it becomes a viable alternative to fossil fuels.



Solar cells in commercial production today are expensive, around $6 per watt. To understand what that means, consider this: If you install $600 worth of solar cells, you can power a typical light bulb for 25 years, figures Ron Pernick, co-founder of renewable-energy consultancy Clean Edge in San Francisco. That’s about twice the cost of coal-based electricity.



Through various technological improvements, solar-cell prices have typically fallen by 5% to 6% a year — but no more, because cells are manufactured through complex processes similar to those employed for making PC processors and memory cards.



NARROWING THE GAP. To bridge that price gap, scientists have long attempted to develop so-called plastic solar cells. Essentially, they’re a thin film that can be manufactured through a much cheaper process, one analogous to a newspaper printing press. They can be flexible and light. Plastic solar cells can also, potentially, be simply sprayed onto any surface — and, voila! — that wall, roof, or consumer electronics case becomes a solar-energy collector. Goodbye, ugly solar-panel roofs. Goodbye, lead storage batteries. Welcome, walls, cars, MP3 players, even shirts doubling as electricity generators.



A person could, potentially, unfurl a roll of such plastic solar cells in a field and create a huge solar farm in a matter of minutes, says Sargent. The beauty of plastic solar cells is that they do away with the costly installation required for traditional, heavy solar panels.



On the downside, today’s plastic solar cells are highly inefficient. They only convert about 6% of the sunlight that hits them into energy. Standard solar cells can have 30%-plus efficiency. That’s why no company produces plastic solar cells today, though one, startup Konarka in Lowell, Mass., plans to begin selling its cells for use as a supplemental energy sources for consumer electronics later this year, says Daniel McGahn, the outfit’s executive vice-president and chief marketing officer. Konarka is mum on its product’s features, but McGahn admits that even under optimal conditions, the cells are only 7% efficient.



Plastic solar cells are also terribly expensive. They can cost 10 times more than the traditional, semiconductor solar cells.



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