GaAs Solar Cell Nanowires Could Boost Commercial Solar Module Efficiency 25%

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Sol Voltaics, a Swedish startup company, has received a $6.2 million loan from the Swedish Energy Agency to produce Gallium Arsenide (GaAs) nanowires (SolInk) for use in solar module. This may be bigger than it sounds.

Image Credit: Christine Daniloff/MIT
Image Credit: Christine Daniloff/MIT

Gallium Arsenide is a highly efficient semiconductor material tested in some solar panels which has achieved efficiency ratings in excess of 40%, which translates to an outstanding power-to-size ratio of 400 watts per square meter of solar panels.

In the case of this project [PDF], the gallium arsenide semiconductor material will be used to create a layer for use on top of conventional solar modules to enhance their efficiency by 25%, basically as a hybrid solar module.

So, a 15% efficient solar module could be increased to 18.75%, or a 20% efficient solar module could be increased to 25%.

The GaAs nanowires are solar cells which are 1 to 2 microns long and approximately 100 nanometres in diameter. The layer of nanowires capture sunlight more effectively using wave-concentrated photovoltaics.

“Solink is a gallium arsenide additive for crystalline silicon or thin-film solar modules that enables modules to convert more of the sun’s light into electricity,” Sol Voltaics writes [PDF]. “Gallium arsenide is the most efficient solar material available today, but it has been confined to niche markets because of high costs. Sol Voltaics solves this problem by minimizing the amount of gallium arsenide needed: less than a gram of nanowires is required to produce Solink-enhanced modules. Each gallium arsenide nanowire in Solink, in fact, is an independent solar cell, making a Solink-enhanced module a vertically stacked device that generates energy from a wider light spectrum than a standard solar panel.”

Dave Epstein, a former VC at Crosslink, and CEO of Sol Voltaics, said: “We have two goals: to make solar more profitable for solar manufacturers and developers and to lower the price of solar energy for consumers, utilities and businesses. We look forward to demonstrating our technology later this year.”

Epstein also noted, according to Greentech Media: “The solar market is booming even though companies are struggling. They are struggling because [the industry is] at the bottom of the cost curve. We’ve mined all of the cost out of solar panels. The only place to improve the economics is in efficiency — to produce more power per panel.”

Epstein also noted a wide discrepancy between the cost of higher efficiency panels, which sell at an average of $0.94 per watt, and lower efficiency panels that are projected to hit $0.42 per watt. Epstein added, “People already don’t want these low-efficiency modules — the projections going down to 42 cents will happen for lower-end modules.”

More efficient solar systems require smaller panels, potentially resulting in a lower installation cost, as well as lower shipping and storage costs.

The Swedish company has raised $11 million so far from its investors: Foundation Asset Management, Industrifonden, Teknoinvest, and Alf Bjorseth of Scatec. It seeks to raise another $10 to 20 million this year.

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Nicholas Brown

Has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

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