Spintronic OLEDs could be brighter and more efficient

‘It’s a completely different technology,’ said Valy Vardeny of Utah University who has created a prototype spin-polarised OLED that produces an orange colour operating at -33ºC.

The latest work was actually made possible by another device called an organic spin valve.

These are essentially electrical switches — found in computers, TVs and mobile phones — that use a property of electrons called spin to transmit information. Spin is defined as the intrinsic angular momentum of a particle where up and down can correlate to the zeroes and ones in binary code.

Organic spin valves are composed of three layers: an organic layer that acts as a semiconductor sandwiched between two metal electrodes that are ferromagnets.

A low voltage is used to inject negatively charged electrons and positively charged electron holes through the organic semiconductor. When a magnetic field is applied to the electrodes, the spins of the electrons and electron holes in the organic semiconductor can be manipulated to align either parallel or antiparallel.