Nano-sized “popcorn balls” could be used to boost the efficiency of solar panels
Hardly a week goes by these days without a new solar panel technology development in the news. You would think the country was plastered in solar sheets with all the work currently being done. Let’s hope the stories soon turn to how we’re going to make this all affordable enough to support widespread installations. In the meantime, today’s innovation.
If you’ve been following our recent series of articles on solar cells, you’ve likely noticed the focus falls roughly into two categories: how to make the panels thinner, lighter and more flexible; and how to make the cells more efficient.
Currently, the best we can do on the efficiency scale hovers right around 18 to 20 percent. Scientists are constantly looking for new ways to capture more of that remaining 80-some percent of energy in the sun’s rays that goes unclaimed. While the approach the researchers at the University of Washington took was not intended immediately to maximize efficiency, it is at its core a method for capturing more light.
Dye-sensitized solar cells are a type of panel more akin to the thin film sheets we’ve been seeing recently than to the rigid silicon cells with which we’re all familiar. They are very cheap to manufacture, which is their primary selling point. On the other hand, they are about half as efficient as better cells.
In a novel approach to boosting their capabilities, the researchers created “popcorn balls” out of nanometer-sized kernels of light-absorbing material. By clumping hundreds of minuscule grains into clusters of large grains, they were able to harness the advantages of both sizes. The small grains provide a large surface area for maximum absorption, while the large grains are closer to the wavelength of visible light and so ricochet the light into the smaller grains.
The UW scientists discovered the combination effectively doubled the cells’ efficiency. Before we celebrate the arrival of a new benchmark of success, we should note that these particular dye-sensitized cells began with an efficiency of 2.4 percent. They used a compound which is very easy to work with, but poor in absorption. The hope is that moving to more difficult but better performing material will eventually lead to breaking that twenty percent barrier.
Via PhysOrg
Thanks to inkjet printing, clothes embedded with solar cells are just around the corner
Back to the Future II was a bit of a disappointment in the face of the original. Granted, it was hamstrung by the throw-away ending of the first, but it did have that brilliant opening sequence with the hoverboards. How much did you want a hoverboard after seeing that? Not to mention, the computerized, self-drying jacket Marty puts on to blend in. The stuff of fantasy, right? At least for the latter, not for much longer.
The traditional components in solar panels—silicon and glass—made them rigid and heavy, limiting their use to a narrow range of applications. But the recent advent of inkjet printing on flexible mylar has given manufacturers the ability to use solar cells in ways previously not possible.
Fujitsu Siemens is reportedly only a year away from bringing clothes with solar cells woven into the fabric to market. It’ll be akin to wearing a solar panel into which you can plug your iPod or cellphone when you’re away from the house and need a charge. Or like the popular Solio handheld solar charger, only incorporated into the back of your shirt.
Of course, you’re going to need a lot of bright sun to get the most out of them. Typical silicon cells operate at around 18 percent efficiency, whereas the mylar cells top out at 5 percent. In other words, it might be a while before they hit the racks in, say, the Pacific Northwest.
Via: The Guardian
Harvard University scientists have created solar cells made from a single wire that’s just 300 nanometers wide. The technology could be used to provide electricity to tiny sensors, or lead to cheaper solar power.
Each of the tiny wires is made up of layers of silicon that basically take over the job of semiconductors in conventional solar cells. Eventually, the nanowires could be packaged together into larger arrays, and might even lead to less-expensive rooftop solar panels. This research is just one aspect of a larger effort to make solar power more competitive with cheaper sources of energy, and according to scientists, it’s an important step forward.—Gregory Mone
