Lego brick concept creates efficient solar panels

An international scientific collaboration has resulted in solar cells that are 22% more efficient than their previous incarnations. Scientists have discovered that covering solar panels with aluminium studs helps to bend and trap light in the absorbing layer, increasing the amount of energy extracted from the captured sunlight.

At the microscopic level, the studs make the solar panels look similar to interlocking Lego bricks.

“In recent years, both the efficiency and cost of commercial solar panels have improved but they remain expensive compared to fossil fuels,” said Dr Nicholas Hylton from the Department of Physics at Imperial College London, lead author of a study on the panels which is published in the journal Scientific Reports.

“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.

“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.”

Along with researchers from Belgium, China and Japan, Dr Hylton attached rows of aluminium cylinders measuring just 100 nanometres across to the top of the solar panel where they interact with passing light, causing individual light rays to change course.

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 it into the solar cells,” Dr Hylton said.

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

According to the researchers, 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.