Researchers have developed solar technology integrating nanowires that could capture large quantities of light and produce energy with incredible efficiency at a much lower cost.
This technology is possibly the future for powering microchips and the basis for a new generation of solar panels.
Despite their size, nanowires have tremendous potential for energy production.
“These nanowires capture much more light than expected,” Anna Fontcuberta i Morral said about her research.
Nanowires are extremely tiny filaments–in this case able to capture light–with a diameter that measures tens to hundreds of nanometers, where a nanometer is one millionth of a millimeter.
These miniscule wires are up to 1000 times smaller than the diameter of human hair, or comparable in diameter to the size of viruses.
When equipped with the right electronic properties, the nanowire becomes a tiny solar cell, transforming sunlight into electric current.
Fontcuberta i Morral and her team built a nanowire solar cell out of gallium arsenide, a material which is better at converting light into power than silicon.
They found that it actually collects more light than the usual flat solar cell – up to 12 times more – and more light means more energy.
The nanowire standing vertically essentially acts like a very efficient light funnel. Even though the nanowire is only a few hundred nanometers in diameter, it absorbs light as though it were 12 times bigger. In other words, it has a greater field of vision than expected.
Fontcuberta’s prototype is already almost 10% more efficient at transforming light into power than allowed, in theory, for conventional single material solar panels.
Furthermore, optimising the dimensions of the nanowire, improving the quality of the gallium arsenide and using better electrical contacts to extract the current could increase the prototype’s efficiency.
Arrays of nanowire solar cells offer new prospects for energy production.
This study suggests that an array of nanowires may attain 33% efficiency, in practice, whereas commercial (flat) solar panels are now only up to 20% efficient.
Also, arrays of nanowires would use at least 10,000 times less gallium arsenide, allowing for industrial use of this costly material. Translating this into dollars for gallium arsenide, the cost would only be 10% per square metre instead of $100,000.
The findings are published in the journal Nature Photonics.