Rooftop solar could be just a spray away
Megan Treacy

One of the more promising solar technologies that researchers have been working on for years is spray-on solar cells. The idea is that being able to apply solar cells to surfaces in such a simple way would allow virtually any surface to become a solar panel. House and car roofs, airplane wings, basically anything that is exposed to sunlight.

Spray-on solar cells could make sloped, rounded, flexible or otherwise unsuitable surfaces for rigid solar panels suddenly suitable. Pretty great, right?

Researchers at University of Toronto believe that they've come up with a technique for spraying on solar cells that is far simpler and cheaper than previous technologies, meaning it has a much greater chance of becoming reality.

Illan Kramer and colleagues have invented a new way to spray solar cells onto flexible surfaces using tiny light-sensitive materials known as colloidal quantum dots (CQDs). These CQDs can be sprayed or printed on an ultra-thin film that could then be applied to any surface like cling wrap.

The researchers say that a surface the size of a car's roof wrapped with CQD-coated film would produce enough energy to power three 100-Watt light bulbs—or 24 compact fluorescents.

"My dream is that one day you'll have two technicians with Ghostbusters backpacks come to your house and spray your roof," said Kramer, a post-doctoral fellow with The Edward S. Rogers Sr. Department of Electrical & Computer Engineering at the University of Toronto and IBM Canada's Research and Development Centre.

What makes this new technology really novel is that Kramer built the device, which he's calling sprayLD, using parts that are readily available and inexpensive. He obtained a spray nozzle that is used in steel mills to cool the steel with a fine mist of water and combined that with some air brushes from an art supply store.

When the technology can be manufactured so easily and cheaply, ramping up production would be simple and that's the key to getting a technology from the lab to our roofs in the near future.

Megan writes for the Technology section of Treehugger. She has been covering clean technology topics since 2008, previously acting as Managing Editor of EcoGeek.org, and she also writes about positive parenting ideas at LightBulbParenting.com. She received her degree in print journalism from the University of South Carolina. She loves being amazed everyday by how technology and human innovation can protect our earth.

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