Solar panels could be made from rows of tiny artificial sunflowers, which automatically bend towards light.
Each artificial sunflower, known as a SunBOT, consists of a stem made of a material that reacts to light and an energy harvesting “flower” at the top, which is made from a standard light-absorbing material commonly used in solar cells. Each SunBOT is less than 1 millimetre wide.
When part of a SunBOT’s stem is exposed to light, it heats up and shrinks. This causes the stem to bend and point the artificial flower towards the light. The stem stops bending once SunBOT is aligned with the light because the bending creates a shadow that allows the material to cool down and stop shrinking.
Ximin He at the University of California, Los Angeles, and her colleagues tested the stems by building a panel of SunBOTs, with and without the bendy material. The team found that the panel of bendy-stemmed SunBOTs was able to harvest up to 400 per cent more solar energy.
“Almost everyone working in the field of responsive or smart materials gets inspiration from nature,” says Albert Schenning at Eindhoven University of Technology in the Netherlands, who wasn’t involved with the work. This is a good proof of principle, he says.