Technology | Jul 29, 2010

Team awarded for better bulb discovery

A team of scientists at Vanderbilt University have been given an award from Popular Mechanics magazine for a discovery that could someday replace the common light bulb, the researchers say.

Led by Vanderbilt associate professor Sandra Rosenthal, the team nearly a year ago discovered a new way to make solid-state lights that produce white light. They say the finding could replace the common light bulb and cut the world's electricity consumption in half.

"We were actually working on something else when this discovery was made," Rosenthal said. "But I think good accidents happen in science a lot more often than scientists want to admit."

The latest award from the magazine is one of several the team has won for experimenting with quantum dots tiny semiconductor crystals of cadmium selenide that absorb light and generate a charge.

Research associate James McBride, who at the time of the discover was studying the way quantum dots grow, had asked Michael Bowers repeatedly to make batches of smaller and smaller crystals.

Bowers, a graduate student in chemistry, put the nanocrystals into a small glass cell and illuminated it with a laser, expecting to see blue light. Instead he saw white.

The surprise discovery was that the tiny crystals can absorb blue light produced by light-emitting diodes, or LEDs, and emit a warm white light.

The researchers say if they can learn how to get the quantum dots to consistently produce white light more efficiently, then quantum-dot-coated LEDs could someday replace light bulbs.

The team is currently working on ways to make the LEDs brighter. Although LEDs are found in accent lighting and flashlights, they are not white enough for general, light-bulb-like use.

The team published a scientific paper on the discovery in fall 2005. Bowers is now writing a second paper that could be published next spring or summer.