Firefly-inspired surfaces improve efficiency of LED lightbulbs

A new type of light-emitting diode lightbulb could one day light homes and reduce power bills, according to Penn State researchers who suggest that LEDs made with firefly-mimicking structures could improve efficiency.

 "LED lightbulbs play a key role in clean energy," said Stuart (Shizhuo) Yin, professor of electrical engineering. "Overall commercial LED efficiency is currently only about 50 percent. One of the major concerns is how to improve the so-called light extraction efficiency of the LEDs. Our research focuses on how to get light out of the LED."

Fireflies and LEDs face similar challenges in releasing the light that they produce because the light can reflect backwards and is lost. One solution for LEDs is to texture the surface with microstructures — microscopic projections — that allow more light to escape. In most LEDs these projections are symmetrical, with identical slopes on each side.