Nanowires, needle-like crystals about the diameter of a virus, can’t be seen with a light microscope, but can give solar energy a massive boost. Led by Anna Fontcuberta i Morral, researchers in the semiconductor lab at the EPFL in Lausanne, Switzerland are developing flat solar panels covered with nanowires that can collect up to 12 times more light than standard flat solar cells.
Propped up on the panel like bristles, the nanowires concentrate light, capturing even more than Fontcuberta’s team expected; their prototype already captures 10 percent more light, and uses 1,000 times less material, than traditional models.
Nano-scale filaments are not a new development in solar technologies; researchers have been working on this kind of technology for years, like the researchers in UC San Diego, Harvard, and the German universities Jena, Gottingen, and Bremen did in 2008. Unlike some earlier applications of the technology, however, these sun-lit nanowires are made with gallium arsenide, which converts light into power better than silicon.
While gallium arsenide is notoriously expensive, its high conversion efficiency is why the material appears in solar panels on spacecraft like the Mars rovers Opportunity and Spirit *. Make the gallium arsenide components into upright nanowires, though, and the amount of the pricey compound needed reduces immensely as compared to flat panels of the material.
Fontcuberta’s team are experimenting with additional efficiency boosters as well; they have also dotted the nanowires with indium arsenide, to act as stimulants to increase light absorbtion even further. Although Fontcuberta says, "It might take ten more years before nanowires can be found on the market." The EPFL’s School of Engineering website reports making this technology available on the market remains the team’s goal.
image via EPFL School of Engineering News
[ * Ed note: as a reader pointed out, while Opportunity and Spirit had gallium arsenide solar panels, the current Mars rover Curiosity is nuclear powered]