Researchers at the University of Toronto have come up with a new kind of spray-on colloidal quantum dots (CQD), which is a breakthrough in the field as it doesn’t bind with oxygen atoms. The later is a problem with CQD as it causes some dots to forgo their electrons and become useless. Tests of this new method revealed a solar efficiency of eight percent, which may be low compared to other technologies, but the researchers are still hopeful their method will prove very useful.

Until now, integrating CQDs into other materials has only been possible through batch processing, but the University of Toronto scientist Illan Kramer has now come up with a method of spraying them onto surfaces in a simple and affordable way. This new system is called SprayLD and is made from readily available and affordable materials such as standard air brushes and spray nozzles. It is capable of spraying CQDs onto various materials, such as plastic or film, without any major losses to their efficiency. Until now, integrating CQDs into materials has only been possible through batch processing, but the SprayLD method could simplify it considerably, as well as make it more widely available to anyone wishing to switch to solar.


Being able to print light-sensitive CQDs onto thin and bendable materials means that they could be applied to just about any surface. According to the scientists, a car roof covered with CQD-covered film would be able to generate enough power for three 100 W light bulbs.

Given the simplicity and affordability of this method, the actual efficiency is perhaps not as important, since virtually any surface could be covered with these solar power harvesting CQDs. This could also conceivably lead to a much wider adoption of solar power harvesting technologies, while also being a lot more environmentally friendly than the solutions currently in use.