Biomimicry of butterfly wings applied to solar panels – In the news

Mengtian Z from Mentone Girls' Grammar School

Solar energy is a form of renewable energy that is harvested by capturing sunlight. One way to harness such energy is the use of Solar photovoltaic (Solar PV) which converts sunlight directly into electricity using solar PV cells (What is solar power?, 2020). Despite being low maintenance and renewable, solar energy only accounts for about 0.1 percent of Australia’s total energy consumption (Solar Energy, 2020) as solar energy is expensive, inconsistent and has to be used straight away as storing solar power requires large expensive batteries, effectively limiting the usage of solar power to daytime only (Pros and Cons of Solar energy, 2020).

Thin-film solar cell is a second generation solar PV cell that is composed of layers of micron-think photon-absorbing materials over a flexible substrate such as metal, glass or plastic. It is cheaper, but less efficient than regular solar PV cells. However scientists have discovered that the way a butterfly’s wings absorbs sunlight can offer a way to improve the efficiency of thin-film solar cells. (Burgess, 2020).

Source - Dr. Raju Kasambe (CC BY-SA 4.0)

Pachliopta aristolochiae, also known as the ‘common rose’ butterfly, is a species of the swallowtail butterflies. It is native to South and South East Asia such as India, Thailand, Malaysia and the Philippines (Pachliopta aristolochiae, 2020). The butterfly has predominantly black wings with some white and red spots. Their wings are covered with scales that not only protects the wings, but are also able to absorb sunlight and turning it into heat. These scales allows the butterfly to capture solar energy over a wide range of angles and wavelengths, due to the butterfly being cold blooded, the black wings enables the butterfly to maintain a high body temperature (From Butterfly Wings to Solar Cells, 2017).

These butterflies were so efficient in capturing sunlight that a group of scientists led by Radwanul  Siddique, a bioengineer at the California Institute of technology, observed the wings under an electron microscope and formed a 3D model of the nanostructures of the wings. The wings are covered in randomly spaced holes that are less than one micrometre wide. The group found that in addition to making the wings lighter, these holes also scattered the sunlight striking them, allowing the butterfly to absorb more of the sun’s heat, which means more sunlight can be absorbed throughout the day (Chen, 2017). Using this, the group created a similar thin-film structure in under 10 minutes, using a layer of tiny holes on top of a silicon base, they found that it picked up roughly twice as much light as other designs (Yirka, 2017).

If the findings of this research manage to transition to commercialisation, it can significantly improve the thin-film technology. As the cheaper thin-film cells lack efficiency compared to conventional solar cells. But if the efficiency of the thin-film cells can be improved using the butterfly wings, it will greatly impact the solar industry.

I personally find this example of biomimicry very fascinating as it is incredible how something so small can provide a solution to big problem. Butterflies are tiny insects that are often discarded however this discovery can be life changing as we are currently in a place in time where we are in need of using new renewable energy sources, and by studying the butterflies, we are one step closer to a greener future.

Bibliography:

Advantages & Disadvantages of Solar Energy (2020), GreenMatch. Retrieved 28 April 2020, from https://www.greenmatch.co.uk/blog/2014/08/5-advantages-and-5-disadvantages-of-solar-energy

Burgess, D. (2020). thin-film solar cell. Encyclopedia Britannica. Retrieved 28 April 2020, from https://www.britannica.com/technology/thin-film-solar-cell

Butterfly wings inspire scientists to boost performance of solar panels - Climate Action (2017). Retrieved 28 April 2020, from http://www.climateaction.org/news/butterfly-wings-inspire-scientists-to-boost-performance-of-solar-panels

Chen, A. (2017). Butterfly wings inspire a better way to absorb light in solar panels. Retrieved 28 April 2020, from https://www.theverge.com/2017/10/19/16503258/butterfly-wings-engineering-solar-cell-energy-biomimicry

From Butterfly Wings to Solar Cells (2017). Retrieved 28 April 2020, from http://physicsbuzz.physicscentral.com/2017/10/from-butterfly-wings-to-solar-cells.html

Solar energy. Australian Renewable Energy Agency. (2020). Retrieved 28 April 2020, from https://arena.gov.au/renewable-energy/solar/

Yirka, B. (2017). Black butterfly wings offer a model for better solar cells. Retrieved 28 April 2020, from https://phys.org/news/2017-10-black-butterfly-wings-solar-cells.html

The article above is one of the winning entries of GTAC's Biomimicry Blog competition. The competition challenged Victorian students to submit a blog article detailing an example of scientific and mathematical advances that were inspired by nature. Click here for more information.