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Organic light emitting diode-Smart component for display.

An OLED (OLED) is a diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. This layer of organic semiconductor material is formed between two electrodes, at least one transparent electrodes.

OLED can be used in television screens, computer monitors, small, portable system screens such as mobile phones and PDAs, watches, advertising, information and indication. OLEDs can also be used in the light sources for general space illumination, and the big light-emitting elements. OLEDs emit less light per unit area than inorganic solid-state based LEDs.

OLEDs have advantages over liquid crystal displays (LCD). OLED displays require no backlight to function. Thus, they can display deep black levels and can be thinner and lighter than LCDs. The OLEDs with higher contrast ratios than LCD screens using cold cathode fluorescent lamps (CCFL) or more recently developed LEDs.

OLED components: an OLED is a device which is 100-500 nanometers thick, about 200 times smaller than a human hair. OLEDs can have either two layers or three layers of organic matter in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. In this article we focus on the design of two layers.

An OLED consists of the following:

1.Substrate (clear plastic, glass, aluminum) - The substrate supports the OLED.

2.Anode (transparent) - The anode removes electrons (electrons adds "holes") when a current passes through the device.

3.Organic layers - These layers are made of organic molecules or polymers.

4.Conducting Layer - This layer is composed of organic molecules in the plastic transport "holes" of anode. A conductive polymer used in OLEDs is polyaniline.

5. Cathode: The cathode gives electrons to the emissive layer

OLED is com posed of an emissive layer, a conductive layer, a substrate, and anode and cathode terminals. The layers are made of organic molecules that conduct electricity. The layers have conductivity levels ranging from insulators to conductors, to OLEDs are considered as organic semiconductors.

OLEDs consisted of a single organic layer of poly (p-phenylene vinylene).

Multilayer OLED can have more than two layers to improve device efficiently and effectively conducting properties, the layers are selected using charge injection at electrodes by providing a more progressive electronic profile or block a charge to reach the opposite electrode and wastage.

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Schematic of a two-layer OLED: 1. Cathode (-), 2. Emissive Layer, 3. Emission of Radiation, 4. Conductive layer 5. Anode (+)

ofOLEDs operation:

OLEDs emit light in a manner similar to SLE, by a process called electrophosphorescence.

The process is as follows: 1. voltage is applied across the OLED.

2.An electric current from the cathode to the anode through the organic layers (an electric current is a flow of electrons).

The cathode provides electrons to the emissive layer of organic molecules.

The anode removes electrons from the conductive layer of organic molecules.

3.At the border between the emissive and the conductive layer, electrostatic forces bring the electrons and holes towards each other and they recombine. What happens near the emissive layer, becaue.