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www.tricksworld.net.tc

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Contents

Introduction structure of an Organic LED

Operation of OLED

Commercial uses

Modern technologies in oleds

OLED Versus LED

Organic LED display and liquid crystal display

Advantages Disadvantages

Applications

conclusion

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INTRODUCTION

Organic light emitting diodes (OLEDs) are optoelectronic devicesbased on small molecules or polymers that emit light when anelectric current flows through them.

OLED consists of a fluorescent organic layer sandwiched between

two metal electrodes

Under application of an electric field, electrons and holes areinjected from the two electrodes into the organic layer, where theymeet and recombine to produce light.

OLEDs are light weight, durable, power efficient and ideal forportable applications

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Typical structure of an Organic LED and theMolecular Structure of Alq3 & TPd

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Energy band

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What the Organic Light Emitting Diode Consist of :

The Top Layer is the Cathode layermade of tungsten releases electronswhen current is run through it.

Emissive Layer removes electrons fromthe cathode layer to make light.

Conductive layer is made from a type oforganic plastic that removes theelectron wholes

Then the Anode Layer that consist ofremoving and adding electron holes

while the current is running through itand is made from graphite particles

Followed by the Substrate layer is usedto support the Organic LED and is madeup of glass, clear plastic

http://upload.wikimedia.org/wikipedia/commons/a/a9/OLED_schematic.svg

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Operation of OLED

The organic light emitting diode (OLED) is a p-n diode, inwhich charge-carriers(e-h pairs) recombine to emit photonsin an organic layer.

The thickness of this layer is approximately 100 nm(experiments have shown that 70 nm is an optimalthickness).

When an electron and a hole recombines, an excited state

called an exciton is formed

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Commercial Uses of the Organic LED

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MODERN TECHNOLOGIES IN OLEDs

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OLED Versus LED

OLEDs are made frompolymers, plastics or othercarbon containingcompounds.

OLEDs consume low power

Light-emitting diodes, basedupon semiconductors such asGallium Arsenide, Gallium Phosphide.

LEDs consume high power

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Organic LED display and liquid crystaldisplay

The most sophisticated O.L.E.D. operate much like the color L.C.D.displays found on current laptops.

L.C.D. screen, each pixel is divided into three subpixels, eachfiltered to display red, green or blue light.

OLED displays replace the lamp, the subpixels and the color filterswith rows and rows of red, green and blue O.L.E.D. units.

OLEDs consume low power(1mW) when compared withLCDs(144mW).

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Advantages

Very thin panel.

Low power consumption.

High brightness/ High contrast.

Wide visibility. Quick response time.

Takes less power to run (2 to 10 volts).

Self luminous.

Thinner than LCD.

No power intake when turned off.

Can be viewed up to 160 degrees

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Disadvantages

Engineering Hurdles

The reliability of the OLED is still not up

to par

Overcoming LCDs

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APPLICATIONS

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Conclusion

Organic Light Emitting Diodes are evolving as thenext generation of light sources. Presentlyresearchers have been gong on to develop a 1.5

emitting device. This wavelength is of specialinterest for telecommunications as it is the low-losswavelength for optical fibre communications.Organic full-color displays may eventually replace

liquid crystal displays for use with lap top and evendesktop computers. Researches are going on thissubject and it is sure that OLED will emerge asfuture solid state light source.