Spray-painting solar cells
23 Mar 2013 by Evoluted New Media
University of Sheffield researchers have made solar cells using a spray painting-like process. The method could significantly reduce the cost of solar cells meaning the technology could be provided to developing countries. The process involves spray-coating a photovoltaic active layer by an air based process –similar to spraying regular paint from a can – to develop a cheaper technique which can be mass produced.
Professor David Lidzey from Sheffield’s Department of Physics and Astronomy told Laboratory News: “We have used spray-coating as it is a cheap, easy, low energy-input method to cover large areas at low cost. It is already widely used in industry, so we thought that if we could adapt it to make photovoltaic devices, it would help reduce barriers to commercialisation.”
The researchers found the performance of their spray-coated solar cells to be similar to more traditionally-manufactured cells. Most solar cells are manufactured using special energy intensive tools and using materials like silicon that themselves contain large amounts of embodied energy. By comparison, plastic requires less energy to make; so spray-coating a plastic layer would significantly reduce the overall energy used to make solar cells.
Lidzey explained the method the group use to make a photovoltaic device which is detailed in Advanced Energy Materials: “We already make solar cells in our group by taking a piece of glass coated with indium tin oxide (acting as the anode), then coating a layer of photovoltaic 'ink' and then covering this with a thin layer of aluminium (to act as the cathode). Here, we used a commercial USI ultra-sonic spray-coating machine to spray-coat a thin-film of the photovoltaic ink.”
The only downside of the technique is that the plastic needed for the spray coating is not currently as efficient at generating electricity as cells made from silicon.
“Our plan is now to explore fabricating larger and larger sized photovoltaics by spray-coating. We also wish to further improve device efficiency, and to explore the nanoscale structure of the materials within the spray-coated films and compare them to regular spin-cast films,” said Lidzey.
Box out: See a video of the technology in action at labnews.co.uk
Paper: Fabricating high performance, donor-acceptor copolymer solar cells by spray-coating in air http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291614-6840
