17 November 2017

Butterfly wings inspire scientists to boost performance of solar panels

Scientists have discovered that the way butterfly wings absorb sunlight could offer engineering insights on how to improve the efficiency of thin-film photovoltaic modules.

Researchers from the Karlsruhe Institute of Technology (KIT) in Germany have studied the common rose butterfly, due to the fact that this particular species' wings are completely black.

Dr. Hendrik Hölscher of KIT’s Institute of Microstructure Technology explains: “The butterfly studied by us is very dark black. This signifies that it perfectly absorbs sunlight for optimum heat management. Even more fascinating than its appearance are the mechanisms that help reaching the high absorption”.

Using a special microscope they discovered that the tiny nanoholes in this species’ wings are found in different sizes, varied between 133 to 343 nanometers, allowing the wings to absorb light at a variety of different angles.

When engineers imitated the pattern and size of the holes in the silicon-absorbing layer of a thin-film, the results showed that it enhanced the absorption of light,  significantly increasing its efficiency.

“The optimization potential when transferring these structures to photovoltaic systems was found to be much higher than expected”, Dr. Hölscher said.

In relation to a smooth surface, the absorption rate of perpendicular light increased by 97 percent and reached a 207 percent increase at an angle of incidence of 50 degrees.

Dr. Hölscher commented: “This is particularly interesting under European conditions. Frequently, we have a diffuse of light that hardly falls on solar cells at a vertical angle”.

If the findings of the research manage to make the transition to commercialisation and be used in industrial scale applications, it will have significant implications for the thin-film photovoltaics technology.

For example, thin-film PVs are considered lighter and cheaper to manufacture but lack efficiency in comparison to conventional crystalline solar cells.

The research team argues that any kind of thin-film PV technology can be improved with such nanostructures, signaling positive advancement in the solar industry.

The research was published in the Science Advances journal. You can access the published paper here

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