Spray-on solar offers cheap alternative to silicon cells
A team of scientists at the University of Sheffield have developed a spray-painting method for applying new, cost-effective solar cells.
The scientists utilized new perovskite solar cells - which have a lower material cost than traditional silicon based solar cells - and applied the cells using a spray-painting method which could have low-cost applications for high-volume manufacturing industries.
The experts from the University's Department of Physics and Astronomy and Department of Chemical and Biological Engineering had previously used the spraying method to produce solar cells using organic semiconductors, but this new method which uses perovskite-based PV cells could be more efficient and have lower material costs.
Explaining the benefits of the discovery, Professor David Lidzey said: "The best certified efficiencies from organic solar cells are around 10%.
"Perovskite cells now have efficiencies of up to 19%. This is not so far behind that of silicon at 25% - the material that dominates the world-wide solar market."
He added: "The perovskite devices we have created still use similar structures to organic cells. What we have done is replace the key light absorbing layer - the organic layer - with a spray-painted perovskite.
"Using a perovskite absorber instead of an organic absorber gives a significant boost in terms of efficiency."
Perovskite-based photovoltaics were first demonstrated in 2012. While most solar cells used today are manufactured using energy intensive materials such as silicon, perovskite requires far less energy to manufacture. By applying the material using spray-painting, the overall energy used to make the cell could be further reduced.
The Sheffield researchers have already developed a prototype using the spray-on solar cells with up to 11% efficiency.
Ultra-thin solar cells applied through printing or spraying, known as 'roll-to-roll' processing, could dramatically cut the cost of solar and allow for flexible installations on buildings or devices.
Professor Lidzey added: "This study advances existing work where the perovskite layer has been deposited from solution using laboratory scale techniques. It's a significant step towards efficient, low-cost solar cell devices made using high-volume roll-to-roll processing methods.
"I believe that new thin-film photovoltaic technologies are going to have an important role to play in driving the uptake of solar-energy and that perovskite-based cell are emerging as likely thin-film candidates."
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