By Liz White, UT staff
Nashville, Tennesssse-LEDs coated with a thin layer of special microscopic beads called quantum dots have the ability to emit white light, and may eventually make conventional lighting technology redundant.
And as often happens, an accidental turn of events led to this discovery.
To make the dots into a coating, Michael Bowers, a graduate student at Vanderbilt University, mixed them with a polyurethane wood coating-an idea culled from another student doing thin film research, who had been working on his parents' summer cabin.
But Bowers was not looking for white light sources. As described in Vanderbilt's online research journal (see link below), he originally made the quantum dots for a colleague, who wanted smaller and smaller types, which led Bowers to produce what are christened "magic-sized cadmium selenide nanocrystals."
And when he illuminated the crystals with a laser, they emitted a warm white light.
Quantum dots have the basic property, used in fluorescent labelling in biomedical applications, of producing a dozen different distinct colours of light simply by varying the size of the individual nanocrystals.
This new ability of Bowers' quantum dots, to spontaneously produce broad-spectrum white light, may have far-reaching effects in making lighting systems that are longer lasting and cheaper than fluorescent tubing and conventional systems.
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