Improving LED lighting

(Press-News.org) CORAL GABLES, FL (June 20, 2011) — University of Miami professor at the College of Engineering, Jizhou Song, has helped design an light-emitting diode (LED) light that uses an array of LEDs 100 times smaller than conventional LEDs. The new device has flexibility, maintains lower temperature and has an increased life-span over existing LEDs. The findings are published online by the "Proceedings of the National Academy of Sciences."

Incandescent bulbs are not very efficient, most of the power they use is converted into heat and only a small fraction of the power gets converted to light. Since LEDs reduce energy waste and present an alternative to conventional bulbs. In this study, the scientists focused on improving certain features of LED lights, like size, flexibility and temperature. Song's role in the project was to analyze the thermal management and establish an analytical model that reduces the temperature of the device.

"The new model uses a silicon substrate, novel etching strategies, a unique layout and innovative thermal management method," says Song, co-author of the study. "The combination of these manufacturing techniques allows the new design to be much smaller and keep lower temperatures than current LEDs using the same electrical power." In the future, the researchers would also like to make the device stretchable, so that it can be used on any surface, such as deformable display monitors and biomedical devices that adapt to the curvilinear surfaces of the human body.

### The study is titled Unusual Strategies for Using InGaN Grown on Silicon (111) for Solid State Lighting. The corresponding author is John Rogers, the Lee J. Flory Founder Chair in Engineering and professor of Materials Science and Engineering at the University of Illinois at Urbana-Champaign (UIUC). Other senior authors include Ralph Nuzzo, G. L. Clark professor of Chemistry at UIUC, and Yonggang Huang, Joseph Cummings professor of Civil and Environmental Engineering and Mechanical Engineering at Northwestern University.

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