As more and more companies turn to renewable energies to power their plants and businesses, researchers behind the scenes are working hard to come up with ways of improving existing sources, making them more efficient and able to meet the needs of a growing market. In an effort to improve solar cell efficiency, researchers at Lund University in Sweden have shown that it may be possible to use nanowires to manufacture solar cells, a breakthrough that could make the cells much more efficient than they are today.

About the breakthrough

According to Renewable Energy Magazine, the Swedish scientists used nanowires made of indium phosphide to improve the ratio of the electrical output of a solar cell to the incident energy in the form of sunlight. According to Lund University, the team was aiming to reach a level of 10% efficiency, but instead reached an efficiency level of 13.8%, a result they say could lead to the development of even more efficient solar cells in the very near future. Discussing the results, coordinator of the project Knut Deppert is quoted as saying: “I am very proud of such a great result – it has well exceeded our expectations. We will of course continue the research on nanowire solar cells and hope to achieve an even higher level of efficiency than the 13.8 per cent that we have now reported.”

Author of the team’s findings, Magnus Borgström adds: “Our findings are the first to show that it really is possible to use nanowires to manufacture solar cells. The right size is essential for the nanowires to absorb as many photons as possible. If they are just a few tenths of a nanometre too small their function is significantly impaired.” After having identified the ideal diameter of the nanowires and how to synthesise them, the Lund researchers have high hopes about how their research could change the face of solar energy in years to come.

What does it mean for the future of solar energy?

The most attractive thing about the development is the cost-incentive for using solar cells made with nanowires over traditional solar cells. According to Lund University, silicon solar cells used to supply electricity for domestic use are cheap but not at all efficient. The reason being, that one single material can only absorb part of the spectrum of the light. While research to combine types of semiconductor material and allow cells to make efficient use of a broader part of the solar spectrum is currently in process, the cost would make material unaffordable for use by businesses, or in the home.

With nanowires however, because of their small dimensions, the same sort of combinations can be created with less effort, offering high efficiency at a lower cost. The process is also said to be less complicated, since nanowires can generate power at the same level as a thin film of the same material, even if they cover only 10% of the surface.

Nanowires, which operate like antennae, are installed on surfaces that measure one square millimetre. Each square can contain approximately 4 million nanowires, resulting in a solar cell that can generate much more power than silicon solar cells currently on the market. While the nanowire-equipped solar cells have yet to leave the laboratory, the scientists hope that could be used one day to equip large solar plants in sunny regions around the world.

 image credit: IBM Research

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