A microscopic pattern on the wings of a butterfly has shown scientists how to capture more of the sun’s energy in solar cells.
The scales of the black-colored common rose butterfly are topped with an irregular lattice of chitin and melanin. Those structures drew the attention of Radwan Siddique, an engineer trying to develop a technique for building 3D nanostructures as part of his doctoral work at Germany’s Karlsruhe Institute of Technology.
Siddique told Seeker he came across a description of the butterfly’s wings in the course of his research. The lattice helps the cold-blooded insect regulate its body temperature, keeping it warm enough to fly in cool weather, he said.
“I was so intrigued that I literally went to a lot of butterfly nurseries and gathered several butterflies,” said Siddique, now a post-doctoral researcher at Caltech. “The black butterfly was one of them. I was putting them under SEM [an electron microscope] and looking at the structures.” It openings are less than a millionth of a meter wide, but they scatter light and help the butterfly absorb more of the sun’s heat.
“They use those nanostructures to improve absorption,” he said. “So I asked, ‘Can we use the same nanostructres in this type of solar cell, which is not highly used because the absorption isn’t that good?’”