Searching for ways to improve solar cell efficiency, a team of scientists found that tiny structures in the human eye have special mechanisms that can be adapted to silicon solar cells to make them better at collecting light.
Many research teams have looked towards nature to find inspiration for improvements in various technologies. This is often referred to as biomimicry, or “mimicking” animals’ and natural processes in order to make an artificial creation act just like a real living organism. Strangely enough, most scientists always look out for interesting behavior or special abilities or processes that are characteristic for members of the living flora and fauna. However, somehow they have neglected the fact that we, humans, are also part of nature.
Now, a team from Helmholtz-Zentrum Berlin and the Max Planck Institute for the Science of Light, decided to do a different kind of biomimicry- the one where they search for hints that our bodies can give in order to improve the existing solar cell technologies. Actually, they did not need to look very far- the answer was in the eyes.
The guys discovered that the small structure inside our retina, known as fovea centralis, which allows us to see everything in great detail, contains tiny inverted cones, packed very close to each other and connected to nerve cells. These are able to capture very high amounts of light, especially if the environment is very well-lit.
This ability of our eyes triggered quite an interest in the team, who decided to simulate the light-trapping process of the fovea, using silicon. The scientists found that their artificial cones were able to boost light absorption of a thin-film solar cell by an incredible 65%. They also noted that the efficiency of power conversion was 60% higher when compared to optimized nanowire arrays.
Now, the best part- apparently there is no need of expensive technology or special methods to engineer the silicon cones. Following a standard semiconductr process, the artificial fovea can be easily made, while to make them work, the only thing that is needed is a simple silicon substrate that can contain the tightly packed cones. Full details can be found in their publication in the journal Nature Scientific Reports.
The team is currently working on scaling up the technology, as well as searching for ways to implement it in LEDs and sensors.
Image (c) S. Schmitt/MPL