Fovea centalis is the name given to the small structure located within the eye that is responsible for making our central vision sharp. A team of scientists at Helmholtz-Zentrum Berlin and Max Plank Institute for the Science of Light believes that this structure could hold the answers to a big boost in the efficiency of solar cell. The team managed to extract the mechanism from this structure and imparted it to silicon as a surface for collecting light in the solar cells.
The fovea centralis got the name because it is essentially a pit located in the center of the macula of the retina. It has a number of cones which are closely packed and inverted, and which have been connected to nerve cells directly. They provide the visual details responsible for us to read or watch TV.
The team was able to note how these peculiar cones were able to trap high intensity of light in well lit environments and decided to use the same approach for collection and conduction of light in photovoltaics. The experiment proved to be a success with their silicon version allowing them to increase light absorption by 65% in a thin-film solar cell when compared with traditional silicon film. Power conversion efficiencies noted an improvement of 60%.
The scientists were not expecting this much of a boost and it did come as a surprise to them. They have concluded that this approach is far better when compared with the deploying of carpet of nanowires since these nanowires lose efficiency when they move closer together. The funnels’ absorption, however, increases when they become packed.
The funnels also don’t require any special engineering for production. The team was able to develop the micron-sized funnels with the help of semiconductor processes followed by packing them into a shoulder-to-shoulder style in a substrate of silicon.
Silke Christiansen, lead researcher, says that her team is working to further enhance the thin-film solar cells and would like to come up with a way to scale the design so that it can work in a large area while being economical.