Scientists at the University of Toronto have been aboard the quantum dot train for some time now and their latest breakthrough involves a new method for spraying solar cells onto flexible surfaces, a development that could one day see them coat anything from bicycle helmets to outdoor furniture.

In such spray on solar cells, quantum dots would act as the absorbing photovoltaic material. Because they have a band gap that can be tuned by altering the size of their nanoparticles, they can be made to soak up different parts of the solar spectrum. This could prove particularly valuable if they were to be used in multi-junction solar cells, where dots small and large could sit alongside each other to widen the cells' energy harvesting potential.

Earlier this year, University of Toronto scientists developed a new kind of CQD that doesn't bind with oxygen atoms, a problem that causes some dots to forgo their electrons and become useless. The researchers recorded a solar efficiency of eight percent, much less than that of commercially available panels, but were optimistic about the dot's potential to power new kinds of devices.

The scientists say that until now, integrating CQDs into materials has only been possible through batch processing, a procedure that is inefficient and expensive. But Illan Kramer, one of the university's post-doctoral fellows, has developed an instrument where the dots can be sprayed onto flexible surfaces such as film or plastic, an advance that could make the process a lot simpler.