OLED: A GREAT BREAKTHROUGH IN DISPLAY TECHNOLOGY

OLED: A GREAT BREAKTHROUGH IN DISPLAY TECHNOLOGY

ABSTRACT:

Organic light-emitting devices (OLEDs) operate on the principle of converting electrical energy into light, a phenomenon known as electroluminescence. They exploit the properties of certain organic materials which emit light when an electric current passes through them. In its simplest form, an OLED consists of a layer of this luminescent material sandwiched between two electrodes. When an electric current is passed between the electrodes, through the organic layer, light is emitted with a color that depends on the particular material used. In order to observe the light emitted by an OLED, at least one of the electrodes must be transparent.

Organic EL is obtained simply by placing a charge-transporting and light-emitting organic material between two electrodes (one of which is transparent) and applying a suitable bias. The organic material may be either a polymer, deposited by various solution processing techniques, or low molecular weight molecules (commonly called “small molecules”), deposited by evaporation or sublimation in vacuum. Total device thickness (excluding the substrate) is less than 1 micron. When biased, charge is injected into the highest occupied molecular orbital (HOMO) at the anode (positive), and the lowest unoccupied molecular orbital (LUMO) at the cathode (negative), and these injected charges (referred to as “holes” and “electrons,” respectively) migrate in the applied field until two charges of opposite polarity encounter each other, at which point they annihilate and produce a radiative state.

for more info visit.
http://www.enjineer.com/forum