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Paper your house with energy
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Toronto Star- A new generation of solar panels could let you wallpaper your house with solar cells, wear them on your T-shirt or stick them on your iPad.
Researchers at Massachusetts Institute of Technology have come up with a new process that allows photovoltaic cells, which convert light into electricity, to be printed in ultrathin layers on ordinary paper or plastic.
“Installation may be as simple as cutting paper to size with scissors, or tearing it by hand and then stapling it to roof structures or gluing it onto walls,” say the researchers.
The panels can even be folded and unfolded without losing their ability to generate power.
The new technique is a sharp contrast from traditional solar panels, in which the polymer material that carries the electric current must be painted as a liquid on ultra-smooth surfaces.
That can mean expensively manufactured glass, or special ultra-smooth plastics. Paper, on the other hand, is about 1,000 times cheaper than glass and 100 times cheaper than plastics now used to construct photovoltaic cells.
Since material that supports the solar cell (known in the trade as the “substrate”) can make up as much as 60 per cent of the cost of a photovoltaic cell, the saving is significant.
“Additional cost savings are anticipated to accrue from the combination of low weight and the ability to achieve a compact form by folding or rolling for transport from the factory to the point of use,” the paper says.
Traditional methods of making photovoltaic cells also require very high temperatures. The new method – which prints the circuitry on the substrate with a vapour rather than a liquid – works at about 120 degrees Celsius.
That’s low enough not to damage ordinary paper or fabric. The technique also employs “no solvents or rare elements,” the paper says.
Of course, the new process isn’t quite as simple as getting a paper copy from the office printer.
The printing is done in five separate layers, in a vacuum. But an MIT release says that’s not a huge technological challenge. The process is similar to the one used to put the silvery lining on a bag of potato chips, so it’s already being done on an industrial scale.
Another issue is longevity. Paper is fragile.
The researchers have protected the printed circuits by laminating the paper with a thin layer of plastic, which they say “significantly improves lifetime.”
One solar cell in the lab, printed on paper and protected by a layer of plastic, has been working for 6,000 hours, powered by sunlight.
Another continued to work after going through a laser printer.
More work needs to be done, but the researchers’ paper optimistically says there is “near-term potential” to use the new cells in “new venues and nontraditional media.”
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