Published on April 19th, 2012 | by Charis Michelsen4
New Organic Solar Cells Should Make Great Tinted Windows
April 19th, 2012 by Charis Michelsen
Electricity-producing windows may be the next fabulous innovation in solar technology — we’ve already written several stories about a US company working on solar windows and one about a UK company working on his tech. Apparently, a small German startup company based in Dresden is working on such tech as well. Heliatek, funded by Bosch, BASF, and others, has figured out how to make a semi-translucent, flexible, and lightweight solar panel of small organic molecules that could, in theory, be used to make windows.
Just Starting Out
The panels developed by Heliatek involve small organic molecules on a polyester film — sort of like OLED displays on a phone. They’re super light and also fairly bendy. The downside (from the end user point of view) is that they don’t generate quite as much power as a standard solar panel under normal conditions, although they do quite well in both excessive heat and indirect light.
The other issue Heliatek will have to overcome is the cost — since it’s currently operating on a tiny proof-of-concept production line, any available panels are super expensive. If they can raise enough money to build a factory, they’re still looking at something fairly small (74 megawatts, if they can get another 60 million euros) — that doesn’t leave much room for low prices.
Flexible Form and Function
If Heliatek can survive long enough to reach large-scale production, its unconventional organic solar cells should drop far enough in price to be competitive with standard solar panels. Until then, they’re trying to be creative.
One way the lightweight panels come in handy is integration into concrete facades — the panel gets integrated right into the wall. Another method is the super-cool window option mentioned above — the semi-transparency means that the tinted windows (which are pretty cool anyway) would also generate electricity. Even if neither option is used, it’s cheaper to plunk Heliatek’s panels right into a building than normal solar panels since no heavy hardware is needed to anchor panels to a roof, and installation costs are a considerable part of the cost of solar.
Longer Lasting, More Efficient
Heliatek’s other advantage is in its innovative solutions to the organic solar cell problem. OPVs have been around for decades (millennia if you count plants, I suppose), and they’re cheap to make. They do not, however, last particularly long, and they’ve got fairly low conversion efficiencies. Since Heliatek uses oligomers (inherently more stable than conventional polymers), which can be very precisely deposited, that precision then allows for control over film thickness and uniformity, which leads to a more efficient solar cell over all. We’re still talking 8% conversion efficiency (the highest-rated standard mass-production solar cell is somewhere around 20%), but that’s an improvement over polymers.
Making Heliatek’s cells is also a bit more expensive than standard OPV printing, but that process means they can make a tandem solar cell — two layers instead of one. If they can figure out how to tune each layer to convert a different wavelength, they might be able to raise conversion efficiency to competitive levels (12%, perhaps).
They’ve got quite a bit of work ahead of them before they have a commercially viable product. Still — tinted windows that produce electricity, that’s just all kinds of awesome! What do you think? Let us know in the comments, below.