A team in Melbourne Australia has developed a way to create inexpensive solar cells using a standard industrial printer, offering the possibility of incredibly cheap photovoltaic cells -- but there are a couple of reasons not to declare the solar revolution over.
Engineers at the Victorian Organic Solar Cell Consortium (VICOSC) have found a way to use an industry standard, $200,000 screen printer to make photovoltaic cells the size of an A3 sheet of paper, using semiconducting inks. (An A3 sheet is 11.7 by 16.5 inches, about the same size as a page in your local weekly tabloid newspaper.) The team's new printer, essentially the same as is used for commonplace applications such as screen-printing t-shirts and posters, can make a solar cell of that size every two seconds.
VICOSC is a collaboration between Australia's national science agency the Commonwealth Scientific and Industrial Research Organisation (CSIRO), The University of Melbourne, Monash University, and industry partners.
In a press statement, CSIRO scientist Scott Watkins waxed lyrical about the potential applications of his team's new manufacturing methods and their newspaper-sized solar cells. "There are so many things we can do with cells this size," said Watkins. "We can set them into advertising signage, powering lights and other interactive elements. We can even embed them into laptop cases to provide backup power for the machine inside."
In this video, Watkins expands on the theme a bit:
The large size and speedy manufacture of VICOSC's solar cells is the good news. The bad news? The organic compounds that make up the semiconducting "inks" aren't very efficient at converting solar energy to electrical power. According to VICOSC, its printed thin-film solar cells can put out between 10 and 50 watts of electrical power per square meter of solar cell. That broad range means these cells have an efficiency of between 1 and 5 percent, far below the output of solar panels that are readily available on the open market these days.
What's more, the lifespan of these cells might be shorter than their more efficient counterparts: organic semiconductors tend to break down relatively quickly in use.
Still, it's a promising technological advance, and incremental increases in efficiency and longevity are likely forthcoming. In the meantime, even at 5 percent efficiency cheap solar cells could do wonders if they're added en masse to building surfaces, billboards, and -- seeing as the cells can be made translucent -- tinted windows.
And as Watkins points out, the printed cells don't necessarily have to stand on their own, but could conceivably be an add-on for traditional silicon PV panels. "The different types of cells capture light from different parts of the solar spectrum. So rather than being competing technologies, they are actually very complementary," says Watkins.
In other words, a five percent efficient solar cell might not be all that exciting. A printable layer you can laminate to a standard solar cell to boost its efficiency from 20 to 25 percent? That's got our attention.