Solar cells are playing a progressively crucial role in supplying our energy needs, having produced as much as 126% of Scotland’s electricity needs in the month of October. Continual innovation will only spread the technology further, lowering costs while increasing efficiencies. A new step in the right direction comes in a the form of solar cells that can be sprayed on to thin, flexible surfaces, devoid of the heft and chunkiness of traditional solar cells.
Researchers from Toronto University led by Illan Kramer, a post-doctor fellow with The Edward S. Rogers Sr. Department of Electrical & Computer Engineering, published findings in Advanced Materials and Applied Physics Letters, illustrating their novel method of spraying solar cells using a miniscule light-sensitive material known as colloidal quantum dots (CQDs). The approach is scalable and makes spray-on solar cells affordable and easy to manufacture.
“My dream is that one day you’ll have two technicians with Ghostbuster backpacks come to your house and spray your roof,” explains Kramer. The technique is called sprayLD — a play on words for ALD, short for “ atomic layer deposition,” a common manufacturing process that applies a surface coating one atom-thickness atom at a time.
Prior to sprayLD, CQDs could only be applied onto surfaces using a batch processing method, a slow, inefficient, expensive, assembly-line approach to chemical coating. Kramer and Co.’s simplified this technique by incorporating the light-sensitive CQDs into a solution, and blasting it directly onto flexible surfaces like film or plastic, similar to the roll-to-roll coating method used to apply ink on a newspaper. The end result: thin panels with approximately the same efficiency as other thin panels made with a more costly, labor-intensive method.
What’s more, the light-sensitive CQDs can be printed onto a flexible film and used to coat oddly-shaped objects such as electronics, and provide a means of charging then. Kramer explains that a car roof-sized surface coated in CQD can produce enough electricity to power three 100-watt light bulbs.
“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 (ECE), 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.”
To reinforce scalability and low cost, Kramer constructed the sprayLD device using readily available and affordable parts such as the spray nozzle used in steel mills and air brushes sold in art stores. “This is something you can build in a Junkyard Wars fashion, which is basically how we did it,” said Kramer. “We think of this as a no-compromise solution for shifting from batch processing to roll-to-roll.”
Source: Discover News
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