UofT researchers develop spray-on solar power technique

A researcher at the University of Toronto has invented a technique for spraying colloidal quantum dots (CQDs) — microscopic light-sensitive materials – onto flexible sheets of plastic film. Illan Kramer, a post-doctoral fellow in UofT’s Edward S. Rogers Sr. Department of Electrical & Computer Engineering, says the new process is a major step toward making spray-on solar cells easy and cheap to manufacture.

“My dream is that one day you’ll have two technicians with Ghostbusters backpacks come to your house and spray your roof,” says Kramer.

Quantum dots are nanoscale bits of a semiconductor material that can be tuned to capture and convert both visible and infrared light. Printed onto a flexible film, CQDs could be used to coat and produce power from nearly any surface. According to Kramer, a car roof wrapped with CQD-coated film, for example, could power three 100-Watt light bulbs.

Previously, producing CQD-coated surfaces required slow and expensive batch processing. Kramer’s technique, called sprayLD, applies a liquid containing CQDs directly onto film or plastic, similar to applying ink on a roll of news print.

“As quantum dot solar technology advances rapidly in performance, it’s important to determine how to scale them and make this new class of solar technologies manufacturable,” said Professor Ted Sargent, vice dean, research in the Faculty of Applied Science & Engineering at University of Toronto and Kramer’s supervisor. “We were thrilled when this attractively manufacturable spray-coating process also led to superior performance devices showing improved control and purity.”
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