ANU breakthrough: Butterfly effect could boost solar cell efficiency

A team of Australian National University researchers has taken inspiration from the humble butterfly wing to develop a nano-technology that could greatly improve the efficiency of solar cells.

Drawing from the neotropical Morpho Didius butterfly, whose wings have tiny cone-shaped nanostructures that scatter light to create a striking blue iridescence, the ANU team was able to finely control the direction of light in a range of experiments, including tests on next generation solar cells.

Dr Lal said the aim, in terms of solar, was to absorb all of the blue, green and ultraviolet colours of sunlight in the perovskite layer of a solar cell, and all of the red, orange and yellow light in the silicon layer – known as a tandem solar cell with double-decker layers.

It was with these kinds of solar cells that researchers at the ANU surpassed silicon efficiency records just last month.

“Techniques to finely control the scattering, reflection and absorption of different colours of light are being used in the next generation of very high-efficiency solar panels,” said Dr Lal from the ANU Research School of Engineering.

“Being able to make light go exactly where you want it to go has proven to be tricky up until now.

“We were surprised by how well our tiny cone-shaped structures worked to direct different colours of light where we wanted them to go,” he said.

In terms of energy efficiency and passive house and building design, Dr Lal said the technique could also be used in architecture to control how much light and heat passed through windows.

“Using our approach, a window could be designed to be transparent to some colours non-see through and matt textured for others – so there are very cool potential applications in architecture,” he said.

And while the research paper, published in ACS Photonics, flags some constraints on the technology’s performance in tandem solar cells, it notes that the technique for making the nanostructure is “very scalable” and does not require expensive technology.

“These intricate nanostructures grow and assemble themselves – it’s not by precise control with a tiny laser or electrons,” Dr Lal said.

The research paper is published with co-authors Kevin Le (pictured above), Andrew Thomson, Maureen Brauers, Tom White and Kylie Catchpole.