Scientists in Canada have dramatically raised the practical potential of spray-on solar by developing a more efficient method for attaching microscopic light-sensitive materials to flexible surfaces.
The new approach was developed by Ilan Kramer, a post-doctoral fellow from the Edwards S. Rogers Sr. Department of Electrical & Computer Engineering at the University of Toronto. It involves spraying the light-sensitive materials onto complex surfaces using a device cobbled together from cheap and commonplace mechanical parts.
“My dream is that one day you’ll have two technicians with Ghostbuster backpacks come to your house and spray your roof,” said Kramer.
The name for Kramer’s technique, sprayLD, is a play upon the formal acronym used to describe it – ALD, or atomic layer deposition. The method involves spraying light-sensitive materials referred to as colloidal quantum dots (CQDs) upon the desired surface in separate layers which are each a mere atom in thickness.
This method marks a major advance upon the prevailing method of depositing CQDs onto surfaces – batch processing, which remains, slow, costly and inefficient.
SprayLD is capable of applying liquids packed with CQDs onto complex or flexible surfaces in manner akin to the which ink is applied to rolls of paper during the process of newspaper printing.
According to Kramer, the roll-to-roll method makes the application of CQDs far simpler and easier while also permitting their deployment onto flexible materials without incurring major losses in efficiency levels.
In a paper just published in the journal ACS Nano, Kramer and his colleagues used the IBM BlueGeneQ supercomputer to model the application of CQDs and demonstrate why their method is just as effective as, and in certain circumstances superior to, the use of batch processing.
Another striking advantage of the sprayLD device is that it employs mechanical parts which are widely available and for the most part inexpensive. These include the spray nozzles used by steel mills to cool down steel with a mist of water, as well as the types of standard air brushes that can be procured at an art store.
Kramer said the low cost of building the device is a decisive part of why his approach is preferable to batch-processing.
“This is something you can build in a Junkyard Wars fashion, which is basically how we did it,” he said. “We think of this as a no-compromise solution for shifting from batch-processing to roll-on-roll.”