The moth’s inner eye is the deepest black that has been found in nature. It absorbs almost all light with no reflection to help the insect see at night and to protect it from predators that would notice the reflective surface.
Certain species of moths have developed bumps or nanoscopic structures on the surface of their eyes which allows them to absorb light waves. Scientists discovered these bumps in the 1960’s under microscopic experimenting but little has been done with this knowledge until recently.
This knowledge is useful to us because it will increase the efficiency of light absorption in solar cells. Currently solar panels are expensive to manufacture plus a lot of light is lost due to reflection on the anti-reflective silicon coating that is used which could be translated to energy if harvested.
Different people and companies are researching and creating solar cell products based on the structure of the moth’s eye.
Peng Jiang, an assistant professor at the University of Florida, along with partners, Chih-Hung Sun of the University of Florida and Bin Jiang at Portland State University are working to improve solar cell cost and efficiency. Peng Jiang states,
“Moth eyes are not very reflective,” he points out. “We found our inspiration in nature, trying to mimic the natural nanostructure.”
To reproduce the moth’s eye effect they are using a spin coating technique with nanoparticles that displace themselves at will during the process which creates the necessary ridges that mimic the eye.
This process is fairly inexpensive, which will decrease consumer costs, and it uses advanced technology to improve solar cells.
Peng Jiang’s process creates a surface that has a less than 2 percent reflection whereas current coatings have a 35-40 percent reflection ratio.
Other companies that are using this breakthrough technology are Reflexite and The Fraunhofer Institute for Mechanics of Materials IWM.
These companies have developed new fabrication methods in plastic injection molding which allows for the design of light-absorbing, non-reflective, strong, and easily maintained plastic coatings.
The trick to their successful development of new products based on the moth’s eye is that the nanoparticles must be smaller than the waves of light to be efficient at absorbing that light and are shaped similarly to the eye with hexagonal patterns covering the surface.
This process is similar to soundproofing a room with foam. The patterns are crucial to the outcomes.
These companies are using this technology to improve television screens, computer monitors, mobile device screens, eye glasses, typical construction windows, and the coatings used on automobile gauges such as the speedometer.
If a moth’s eye can enlighten our energy harvesting by a non-reflective, less expensive surface, what will be discovered next? As more scientific breakthroughs evolve to enhance today’s technology, the future holds no bounds.