The average amount of daily sunlight for any two locations will vary to some degree, especially when comparing locations like London, England to equatorial Africa, or even Seattle to Los Angeles here in the United States. Despite this obvious fact, all solar cells coming off the market are uniform in design, varying only by company design or cell type.
Now a UK company, Quantasol, has devised a way to make their solar cells site specific, thus maximizing the solar energy recovered over the long term. On top of that Quantasol managed to break a 21-year-old world record in efficiency for their type of solar cell. That type is a Gallium Arsenide (GaAs) solar cell, first used in space many years ago and still rare in today’s earthbound solar market.
Quantasol’s site-specific secret is not simply in using the more efficient (compared to silicon) and more expensive GaAs semiconductor material. They add a few nanolayers (quantum wells) of Indium Gallium Arsenide (InGaAs) to the mix. These layers can be specifically tuned to absorb light at the most common frequencies for a given area, frequencies that the rest of the GaAs solar cell may not be great at absorbing and converting to electricity.
The result is that over time, according to the company, Quantasol solar cells should extract more solar energy than more conventional competitors. At the same time they’ve managed to increase the record efficiency for this type of solar cell by one-tenth of one percent over the previous world record — the first increase in 21 years.
Quantasol’s tunable solar cells are designed for the commercial market. Although, considering that their semiconductor is more expensive than established silicon solar cells, one can’t help but wonder if the increased cost of the adaptable solar cell will be worth the increase in production. Quantasol claims that their solar cells have a peak conversion efficiency of more than 28 percent, compared to 10-15 percent for conventional cells. Should those numbers hold up in real world use, I suppose this UK company could be on to a worldwide solar innovation.
LINK: News Scientist