Researchers Improve LED Efficiency with Inspiration from Fireflies

The way fireflies light up their lanterns has become an inspiration to increase the efficiency of LED. Researchers at the Pennsylvania State University (Penn State) found out that LEDs made with firefly-mimicking structures could improve lighting efficiency.

Enhancing luminous efficiency of LED has been a research field for many scientists. Stuart (Shizhuo) Yin, professor of electrical engineering at Penn State, noted, "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."

The research team noticed that fireflies and LEDs face similar challenges in releasing the light that they produce because the light can lost when it reflects backwards. 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.

Fireflies' lanterns also have these microstructures, but the researchers found out that the microstructures on firefly lanterns were asymmetric with one side slanted at different angles. The team noticed that other glowing insects have similar structures and decided to try the asymmetric structure approach with LEDs.


(Saphire surface with asymmetrical pyramids to produce more light in LEDs. Image: Penn State)

Researchers successfully applied asymmetrical microstructure and increase light extraction in two different ways. First, the greater surface area of the asymmetric pyramids allows greater interaction of light with the surface, so that less light is trapped. Second, when light hits the two different slopes of the asymmetric pyramids there is a greater randomization effect of the reflections and light is given a second chance to escape.


(Comparison between symmetric and asymmetric structure; image: Penn State)

With the method, the team managed to improve light extraction efficiency to 90 percent and filed a patent on the research. Researchers said that they are looking for cooperation with related manufacturers to commercialize the technology.

The finding was published online in Optik with printed edition releasing in April.

Disclaimers of Warranties
1. The website does not warrant the following:
1.1 The services from the website meets your requirement;
1.2 The accuracy, completeness, or timeliness of the service;
1.3 The accuracy, reliability of conclusions drawn from using the service;
1.4 The accuracy, completeness, or timeliness, or security of any information that you download from the website
2. The services provided by the website is intended for your reference only. The website shall be not be responsible for investment decisions, damages, or other losses resulting from use of the website or the information contained therein<
Proprietary Rights
You may not reproduce, modify, create derivative works from, display, perform, publish, distribute, disseminate, broadcast or circulate to any third party, any materials contained on the services without the express prior written consent of the website or its legal owner.

NF2W585AR-P8 is a dual function LED that provides both white light and high doses of energy geared for inactivation of various prevalent bacteria. With a 405nm wavelength1 die known to be effective in sterilization, this LED can be used t... READ MORE

  The 5050 LED is replacing the 3535 LED, which has long been the leader in the outdoor lighting market. The existing ceramic-based 3535 has excellent reliability but is expensive. At present, the 5050 LED, which has achieved remarkable p... READ MORE