Tiny ‘LEGO brick’ -style studs make solar panels a quarter more efficient

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. Many new, lower cost designs are limited as their layer of light-absorbing material is too thin to extract enough energy.

In new research, scientists have demonstrated that the efficiency of all solar panel designs could be improved by up to 22 per cent by covering their surface with aluminium studs that bend and trap light inside the absorbing layer.

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

The study is published in the journal Scientific Reports by scientists from Imperial College London and international collaborators in Belgium, China and Japan.

“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 from the Department of Physics at Imperial College London.

“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.”

Dr Hylton and his colleagues attached rows of aluminium cylinders just 100 nanometres 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.

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