Could Spray-On Solar Change the Game?

We’ve heard a lot about falling solar prices. Some of that is due to dumping of low-cost panels from China. But there is also a great deal of research being done here in the U.S. and elsewhere that is attacking the problem from many different directions. This is helping to not only reduce cost but to increase efficiency as well.

One area that has shown promise is that of colloidal quantum dots (CQD). These tiny nanotech wonders have a theoretical efficiency of 45 percent, surpassing that of silicon, though no one has come close to achieving that yet. What has been done, however, by researchers at MIT, is the development of production techniques that allows quantum dots to be produced without elevated temperatures or vacuum conditions. That means low cost, with a present conversion efficiency of 9 percent.

One thing to keep in mind with solar is that, given the fact that sunlight is free, the efficiency by which it can be converted into electricity is less important than it is with other sources that require you to pay for the energy. Where it does matter is in two areas: the system cost and the amount of area required.

So if the system cost is low -- allowing you to cover your entire roof at a reasonable price -- which provides enough power even at low efficiency, then who cares? Still, you have all that mounting hardware and labor to install it, right?

The cool thing about quantum dots is that these solar cells can theoretically be sprayed on, eliminating all that mounting hardware and labor and also permitting the cells to conform to irregular and uneven surfaces. Another good thing about quantum dots is their ability to soak up a wider portion of the solar spectrum. One problem with them has been that they lose their effectiveness when they come into contact with oxygen.

Researchers at the University of Toronto, who have been testing out the possibility of spray-on cells, have found a way around the oxygen problem using different materials. “The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency," Professor Ted Sargent said back in June. "The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels."

The new spray-on system, invented by Illan Kramer (pictured above) is called SprayLD. It is built from inexpensive components that are all readily available, such as airbrushes and cooling nozzles used in a steel mill (video).

The vision is that of a Ghostbusters-like team, armed with spray nozzles and wearing tanks strapped to their backs. They say that a surface the size of a car roof could provide 300 watts. That means that the roof of a house could easily provide 10 kilowatts. The entire spray apparatus can be built for less than $1,000. No word yet on how much the spray itself would cost.

The spray-on format makes it easy to apply. Now, if they can get the efficiency up and the cost of the spray down, this is something that could become extremely widespread.

Image courtesy of University of Toronto.

RP Siegel, PE, is an author, inventor and consultant. He has written for numerous publications ranging from Huffington Post to Mechanical Engineering. He and Roger Saillant co-wrote the successful eco-thriller Vapor Trails. RP, who is a regular contributor to Triple Pundit and Justmeans, sees it as his mission to help articulate and clarify the problems and challenges confronting our planet at this time, as well as the steadily emerging list of proposed solutions. His uniquely combined engineering and humanities background help to bring both global perspective and analytical detail to bear on the questions at hand.

Follow RP Siegel on Twitter.