Researchers at Germany's Fraunhofer Institute for Solar Energy Systems have created a solar photovoltaic (PV) cell in the lab that's more than 41.4% efficient. That bests the old record set by the US' National Renewable Energy Laboratory last summer by almost 1%.
They did it by reducing "impurity traps" that exist in the transitions zones between materials within individual solar cells. Silica, a key solar-cell component and one of the most common compounds on earth, often has a lot of impurities that reduce the overall efficiency of a solar cell. These impurities tend to collect where the silica and the substrate materials, gallium-arsenide and germanium in this case, come together.
If a 1% improvement doesn't seem like much, remember that a typical home solar PV system you'd install on your roof today has an efficiency of less than 20%. Although these lab experiments are like the Bonneville Salt Flats of solar energy — don't expect a 41%-efficient solar panel on the market tomorrow — it will make solar energy cheaper over time.
Right now, residential solar power costs about 37 cents per kilowatt-hour, compared to 6 to 8 cents/kwh for non-green electricity, like coal. While those prices depend on a lot of factors, like where you live, how much sun you have and what your local utility uses to generate electricity, any improvement is great. But there's some way to go before solar is truly competitive.