Roll-to-roll process improves viability of spray on solar cells

Illan Kramer and colleagues at the University of Toronto said they have made the breakthrough by devising a new way to spray solar cells onto flexible surfaces using miniscule, light-sensitive colloidal quantum dots (CQDs).

‘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 many different surfaces. However, until now it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing, which is an inefficient, slow and expensive assembly-line approach to chemical coating.

The SprayLD system sends 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.