Researchers have built the first organic LED (OLED) that is controlled by the spin of the charge carriers running through the device, paving the way for future OLED devices to offer increased brightness. Though rumors say Samsung will release a 55-inch OLED TV this fall, don’t expect a spin-OLED on the market soon. This prototype orange OLED only works at temperatures below -33°Celsius (-28°Fahrenheit).
OLEDs contain layers of organic polymers sandwiched between two electrodes. (Organic here refers to molecules containing mostly carbon, hydrogen, oxygen, and nitrogen, like those in our bodies.) These polymers act like semiconductors, so applying voltage across the sandwich generates electrons at one electrode, and their positive partners, called “holes,†at the other. These electrons and holes travel along the polymers, smashing together when they meet. This collision pumps energy into the molecule. It loses that extra energy by emitting light.
But there’s a catch. Polymers only emit light when the spins of the electrons and holes are arranged in particular combinations. Think of spin as a tiny bar magnet inside the electrons and holes. When two spins meet, the north poles of each spin can point the same direction, or they can oppose each other. Both of these combinations can create light, though whether or not they both do it in the same organic semiconductor depends on the individual polymers.
from Ars Technica