RPI Closing 'Green Gap' in LEDs

Researchers from Rensselaer Polytechnic Institute (RPI) has received $1.8 million in federal funding to improve the energy efficiency of green LEDs. As part of the US Department of Energy’s (DOE) Solid-State Lighting Program, the team aims to close the “green gap” in LED technology by doubling or tripling the power output of green LEDs in three years, an advance that ultimately could lead to the replacement of incandescent and fluorescent lamps in general illumination applications.

“Making lighting more efficient is one of the biggest challenges we face,” said Christian Wetzel, Wellfleet Career Development Constellation Professor, Future Chips, and associate professor of physics at Rensselaer. “Substantial reductions in the nation’s dependence on primary energy imports will be possible once highly efficient solid-state light sources replace wasteful incandescent and fluorescent lighting.”

Wetzel will be leading a team of scientists and engineers attempting to help meet the aggressive performance targets laid out in DOE’s solid-state lighting accelerated road map, which calls for the development by 2025 of advanced solid-state lighting technologies that are much more energy efficient, longer lasting and cost competitive than conventional lighting technologies. The prime contender to meet this goal, according to Wetzel, is a white-light unit made from a combination of high-performance red, blue and green LEDs.

Researchers have made major strides in advancing the design of red and blue LEDs, but the technology behind green LEDs has lagged behind substantially, Wetzel said. Green light is an essential piece of the puzzle because it addresses the peak of the human eye’s sensitivity, providing balance to the colors of red and blue light. He plans to focus on aspects of the “piezoelectric effect” — a property of some materials that causes them to produce an electrical field when pressure is applied. By controlling this effect, he and his colleagues hope to develop a process to make higher-intensity green LEDs that convert electricity into light more efficiently.

For more information, visit: www.rpi.edu