A consortium from Australia’s CSIRO and Melbourne and Monash Universities just announced that its printable solar cells are on the verge of commercialization. The technology uses a specially developed ‘solar ink’ that can be printed onto plastic film using existing printers in a similar way to printing plastic bank notes. The team envisions its printed solar cells being used anywhere that plastic is currently used – so they could power anything from laptop bags and device covers to skyscrapers. And best of all, a printer can spit out a solar cell every two seconds!
The Victorian Organic Solar Cell Consortium has been working on printable solar cells since 2007. The team has developed processes that use spray coating, reverse gravure and slot-dye coating, as well as screen printing. Using semiconducting inks, the researchers print solar cells straight onto paper-thin, flexible PET – the same plastic found in water and soda bottles. The cells can also be printed onto steel, or they can be made semi-transparent for window treatments and building cladding. Initial results produced coin-sized cells, but this rapidly progressed to A3-sized sheets. Printing speeds can currently hit ten meters per minute, producing one cell every two seconds.
So far the technology’s main downside is that the cells currently work at only 10 percent of the efficiency of silicon cells. However, the team is expecting to close the efficiency gap soon by improving solar inks so they can generate more electricity. The initial lifespan of the printed solar cells was only six months, but the team is working on improving this to 10 years.
Of the difference between printed solar cells and silicon cells the CSIRO’s Fiona Scholes said, “It would be wonderful if we could achieve a similar power delivery at significantly reduced cost. Silicon is falling in price, but think about how cheap plastic is. The ink is a negligible cost, so the raw materials are very cost effective. This is a big step forward because you can put these cells anywhere you can think of. Also the consistency is better than silicon – they work well in cloudy conditions.”
While the team can’t produce the cells commercially themselves, a number of companies have now stepped forward to discuss manufacturing them. The enormous range of possibilities for applications is naturally generating much excitement, and though the team’s printer costs around $200,000, the economies of scale of commercial production are expected to make the cells very affordable.
Photos by CSIRO