Rose butterfly is a common sight in forests and meadows of India. The butterfly is famous for its velvet black wings, colored body and tail, its day is spent sucking nectar from Zinnias and Egyptian Star-Cluster. And now onwards the butterfly will be known for increasing the efficiency of our Solar Panels.
“I was in a conference and somebody was presenting about butterflies and their nanostructures, and I was intrigued,” says Radwanul Siddique, who is the lead author of a paper published in Journal Science Advances. The paper submitted by Siddique, with inspiration from butterfly nanostructure, illustrates a new design for solar panels that are able to absorb larger amount of sunlight than the conventional Solar Panels.
Siddique tells, “There are so many insects that have structural colors, where their color comes from nanostructures”. Consider the Morpho butterflies that have bright blues and green wings, these colors are gained by tiny tree like shapes in the wings which are less than a millimeter across. The reflection of light at different angles on the nano-structures yield in in different colors, making the butterfly ‘shimmer’ and even change its colors in the air.
The trick is similar in the common Rose butterfly. The velvety black wings are like that because the tiny microscopic holes –they trap and absorb all the light, resulting in a blacker color than it is possible otherwise. This structure caught the attention of the engineer Siddique, a structure that absorbs more of light is exactly what he was looking for.
The nanostructures of the common Rose butterfly were scanned under an electron microscope by Siddique and his colleagues and then they attempted to recreate the structure with a solar cell. Siddique’s team managed to increase the solar cell’s efficiency dramatically by adding tiny microscopic holes in the solar cell.
The question is how adding microscopic holes dramatically increase the efficiency? Most of the light that falls on these holes is completely absorbed even at extreme angles. The conventional solar panels have to be positioned directly towards sun in order to get the maximum efficiency. But when they are at some inclination off the side then their efficiency drops. On the other hand these tiny holes help catch more of the angled light, Siddique’s solar cells have three times more efficient than conventional solar cells at extreme angles.
This is great news for homeowners with rooftop solar installations as they’re generally fixed in one position and produce lots of energy only for a few hours in a day. Siddique’s design can help their solar panels produce more power at all daylight hours, which implies to more power at more times.
The technology is cheap; butterfly uses specific proteins to build those nano-structures. Siddique’s team created artificial versions of the same proteins and applied them to solar cells, creating a cheap and scalable way to produce more efficient solar panels.
Only few years of development is all that is needed to start using Siddique’s design for solar cells on rooftops of all the world.