Let there be Better LED Light

The Math That Promises to Make the World Brighter     Kevin Hartnett,  Senior Writer in Quanta.

The color of LED lights is controlled by a clumsy process. A new mathematical discovery may make it easier for us to get the hues we want.

n elaborate quantum dance powers LED lightbulbs. The more precisely the dance can be choreographed, the closer LEDs will come to fulfilling their promise as the ubiquitous energy-efficient lighting source of the future (LEDs are already efficient, but they could be a lot more so). My latest story, “Mathematicians Tame Rogue Waves, Lighting Up Future of LEDs,” is about a mathematical discovery that allows physicists to plan out that quantum dance step by step, like directors of a Broadway show.

LEDs work when electrons can be coaxed to collide with “holes,” particle-like entities with a positive charge found in semiconducting material. When an electron hits a hole, the LED emits a photon of light.

At least, that’s how it’s supposed to work. In practice, it can be hard to push electrons around with such precision. The semiconducting material used to make most LEDs has a highly messy atomic structure. This means that electrons will sometimes “localize” (or get stuck) before finding a hole. If electrons localize in the wrong place, they emit a phonon of heat instead of a photon of light, and we end up using LED lightbulbs to heat our living rooms. .... "