No, these aren’t solar lightning bolts from Zuul, the gatekeeper of Gozer, or his minions. But someday technicians with ghostbuster-style backpacks may come to spray solar cells on your roof.
University of Toronto post-doc fellow Illan Kramer and his colleagues have just developed a new way to spray solar cells onto flexible surfaces using miniscule light-sensitive materials known as colloidal quantum dots (CQDs). The breakthrough constitutes a major step toward making spray-on solar cells easier and cheaper to manufacture.
While much work remains to be done in determining whether the technology can be commercial viable, the signs are positive. The team was thrilled when the attractively manufacturable spray-coating process – using a standard spray nozzle found in steel mills, and a few airbrushes from an art store — also led to superior performance devices, showing improved control and purity.
The applications are numerous. The ability to spray solar cells onto a flexible film would enable the “wrapping” of many different kinds of irregular surfaces. According to the University, this could include anything from patio furniture to airplane wings.
“My dream is that one day you’ll have two technicians with Ghostbusters backpacks come to your house and spray your roof,” says Kramer.
Kramer calls the 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.
Until now, it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing—an inefficient, slow and expensive assembly-line approach to chemical coating akin to semiconductor manufacture. In contrast, sprayLD blasts a liquid containing CQDs directly onto flexible surfaces, such as film or plastic, like printing a newspaper by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler. In two recent papers in the journals Advanced Materials and Applied Physics Letters, Kramer showed that the SprayLD method can be used on flexible materials without any major loss in solar-cell efficiency.
Using funding from IBM Canada and King Abdullah University of Science and Technology, the team used a consortium supercomputer to model how and why the sprayed CQDs perform just as well as — and sometimes better than — their batch modeled counterparts.