Colloidal Quantum Dots Make Spray-On Solar Cells Possible
Illan Kramer and colleagues have just created a new way to spray solar cells onto flexible surfaces. They are using miniscule light-sensitive materials known as colloidal quantum dots (CQDs).
(Spray-on solar cell video)
"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.
Solar-sensitive CQDs printed onto a flexible film could be used to coat all kinds of weirdly shaped surfaces, from patio furniture to an airplane's wing. A surface the size of your car's roof wrapped with CQD-coated film would produce enough energy to power three 100-Watt light bulbs -- or 24 compact fluorescents.
He calls his system sprayLD, a play on the manufacturing process called ALD, short for atomic layer deposition, in which materials are laid down on a surface one atom-thickness at a time.
Kramer built his sprayLD device using parts that are readily available and rather affordable -- he sourced a spray nozzle used in steel mills to cool steel with a fine mist of water, and a few regular air brushes from an art store.
"This is something you can build in a Junkyard Wars fashion, which is basically how we did it," said Kramer. "We think of this as a no-compromise solution for shifting from batch processing to roll-to-roll."
I read about this idea twenty years ago; sf writer Larry Niven popularized it in his 1995 story The Woman in Del Rey Crater:
Black Power, they call it. It turns sunlight into electricity, just like any solar power converter, but you spray it on.
(Read more about Niven's black power)