When you are looking at better ways to make something glow, what better place to look than one of nature's signature glowing critters, the firefly? Scientists in South Korea have studied the nanostructure of the firefly's glowing belly to create a more efficient lens for LEDs that allows up to 98 percent more light to pass through.
Using an electron microscope, Ki-Hun Jeong of the Korea Advanced Institute of Science examined the firefly's exoskeleton. They found the insect's glowing abdomen or "lantern" was divided into three parts, similar to how LED bulbs are constructed — a reflective cup and a lens sandwiching the light source. Firefly's lanterns have a similar reflective layer, a light emitting layer and a cuticle or outer shell.
The key difference between current LEDs and the fireflies was the scientists found the firefly to have ordered ridges on that outer shell or exoskeleton that surrounded the lighted parts of the abdomen. These ridges allow the light wavelength to pass through the firefly lanterns more effectively.
Taking that discovery, the scientists created a similar pattern by etching dots into plastic. Like the firefly's abdomen, when tested it allowed for more light to pass through. To make the translation from the bodies of individual insects to the more ordered structure of an LED bulb, they created nanopillars molded into the shape of a honeycomb to replicate the curvature and ridges found on the firefly's belly.
While this configuration seems to work best with the wavelength of the firefly's light, the scientists were quick to point out the nanopillars and dots could be adapted to different wavelengths as the transmittance of light is very sensitive to physical dimensions.
A boost of 98 percent more light would certainly make LEDs more efficient and bright. Another reason this breakthrough is significant is that its nanostructure could mean doing away with having to coat the LED lenses with costly anti-reflective coating, ultimately lowering the cost of the bulbs.
That means the future could be filled with brighter LED screens, car headlights or the regular household bulbs, all thanks to the friendly firefly that has finally given up most of its secrets.
The research appears in the October 29 issue of Proceedings of the National Academy of Sciences.