‘LEGO’-Style Solar Panels More Efficient

Scientists have developed ‘LEGO’-style solar panels with aluminium studs that extract more energy from sunlight than those with flat surfaces.

Asian Scientist (Oct. 31, 2013) – An international team of researchers has found that the addition of rows of aluminium studs help solar panels extract more energy from sunlight than those with flat surfaces.

Most solar cells used in homes and industry are made using thick layers of material to absorb sunlight, but have been limited in the past by relatively high costs. Even newer lower cost designs have limited efficencies as their layer of light-absorbing material is too thin to extract enough energy.

In new research published in Scientific Reports, scientists demonstrated that the efficiency of all solar panel designs can be improved by up to 22 percent through the simple method of covering their surface with aluminium studs that bend and trap light inside the absorbing layer.

At the microscopic level, the studs make the solar panels look similar to the interlocking LEGO building bricks played with by children across the world.

“In recent years both the efficiency and cost of commercial solar panels have improved but they remain expensive compared to fossil fuels. As the absorbing material alone can make up half the cost of a solar panel our aim has been to reduce to a minimum the amount that is needed,” said lead author Dr Nicholas Hylton.

“The success of our technology, in combination with modern anti-reflection coatings, will take us a long way down the path towards highly efficient and thin solar cells that could be available at a competitive price.”

Hylton and his colleagues attached rows of aluminium cylinders just 100 nanometers across to the top of the solar panel, where they interact with passing light, causing individual light rays to change course. More energy is extracted from the light as the rays become effectively trapped inside the solar panel and travel for longer distances through its absorbing layer.

In the past, scientists have tried to achieve the light bending effect using silver and gold studs because those materials are known to strongly interact with light, however these precious metals actually reduce the efficiency as they absorb some of the light before it enters the solar panel.

“The key to understanding these new results is in the way the internal structures of these metals interact with light. Gold and silver both have a strong effect on passing light rays, which can penetrate into the tiny studs and be absorbed, whereas aluminium has a different interaction and merely bends and scatters light as it travels past them into the solar cells,” he said.

An additional advantage to this solution is that aluminium is cheaper and far more abundant than silver and gold.

The future success of this technology opens up the possibility of making flexible solar panels that could be applied to any flat or curved surface, which could be used to power everything from domestic appliances to portable electronics like laptops.

The article can be found at: Hylton et al. (2013) Loss Mitigation In Plasmonic Solar Cells: Aluminium Nanoparticles For Broadband Photocurrent Enhancements In GaAs Photodiodes.


Source: Imperial College; Photo: Mr. T in DC/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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