Scientists develop 'Spintronic' LED

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Friday, 13 July 2012 11:33

July 13, 2012

A group of physicists at the University of Utah have developed a new "spintronic" organic light emitting diode (OLED) that could revolutionize lighting by making it brighter, cheaper and more environmentally sensitive than current LEDs.

The technology could be used to improve backlighting for television and computer screens, traffic lights and dozens of electronic devices in addition to illumination.

"It's a completely different technology," said Z. Valy Vardeny, University of Utah distinguished professor of physics and senior author of a recent study on the technology that appeared in the July 13 issue of the journal Science. "These new organic LEDs can be brighter than regular organic LEDs."

The experts created the new LED, which they called a spin-polarized OLED, and stated the prototype produced a bright orange color. In the next two years, Vardeny said, the technology could be used to create red and blue lights also, and in time, it could even generate white light.

But despite the technology's promise, it could still be another five years before the lights are commercially available, as they currently can only function at negative 28 degrees Fahrenheit. The next phase will be to make them functional at room temperature, Vardeny said.

The study received funding from a number of international agencies, including the U.S. Department of Energy and the Israel Science Foundation, which showed great interest in furthering the engineering research Vardeny and his group were conducting.

Like the first LEDs, the OLED uses an organic semiconductor, but it is more than just an electronic device that holds information using the electrical charge of electrons. The "spintronic" device also uses the rotation of electrons to store information.

The spin OLED was developed after piggybacking on "organic spin valve" technology developed in 2004.

"It took us eight years to accomplish this feat," Vardeny said.

According to Ars Technica, the spin valve technology developed in 2004 smashes an orange LED polymer between two ferromagnetic electrodes. One of the electrodes forces electrons into the polymer, while the other injects spin-aligned holes. The spin alignments are controlled by scientists, who in turn control the spin of the charge carriers emitted from the electrodes by using an outside magnet.

The new system will have many benefits, including enabling the use of semiconductors that are less expensive, and are produced with less toxic waste than other silicon semiconductors.

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