POLYMER LED

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POLYMER LED

Presented By

UMAKANTA MOHAPATRO ROLL # EI200113370

December 2004

Under the Guidance of

Mr. Prabhat Kumar Mohapatra

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INTRODUCTION Polymer LED (light-emitting diode)- sometimes

called light-emitting polymer or polyLED - is a

technology based on the use of polymer as the

semiconductor material in LEDs. It is a novel technology to manufacture very thin light sources and displays Polymers are large molecules widely known as

plastics.

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Light Emitting Polymers convert electrical power into visible

light:

Light EmittingPolymer

electrical power

FluorescentPolymerUV-radiation

This is related to the fluorescence of polymers where UV-radiation is converted into visible light:

visible light

visible light

Text

mar

ker

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A polymer needs to show fluorescence and to conduct electricity.

UV radiationvisible light

+

electrical charge

to be a Light Emitting Polymer.

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A thin film of light Emitting Polymer put between two electrodes will glow...

Light Emitting Polymer Device

Substrate

Metallic Counter Electrode

Thin Plastic Film of LEP

Transparent Electrode

Emitted light

+-

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•On each cm² of a device running at standard brightness

this happens1.000.000.000.000.000

times per second!!!

•Positive and negative charge carriers combine and generate an neutral exited

state. This exited state decays and generates Visible light

•If voltage is applied, positive charge carriers

move into the anode,negative charge

carriers into the cathode!

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Like an ink a solution of Light Emitting Polymer can be used to easily "paint" an electrical light source onto an appropriate substrate. it's like 'painting' an electrical light!

+

-

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By engineering the chemical structure of the

Light Emitting Polymer all emission colours can be obtained.

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•Because plastic materials are flexible and robust even non-planar displays can be manufactured. LEP- Non Planar Displays

Light Emitting Polymer Film Transparent Protective Film

Protective Film

Covion- flexible displays

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Polymer electronics laboratory

The photo shows where each of the following steps in the

fabrication sequence takes place. 1) Clean substrates in ultrasonic bath (not shown).

2) Clean substrates in dust free work area.

3) Transfer substrates into glove box.

4) Spin coat polymer film.

5) Transfer parts into glove box.

6) Coat top metal electrodes in vacuum evaporator.

7) Test polymer LEDs.

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Light Emitting Polymers cover a large range of applications:

Easy to use technology.Thin and light weight displays for portable electronics. Very high brightness. Low operating voltage (2 - 6 Volts).All colours possible.All shapes and non-planar displays possible.

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0

2

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6

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0 1 2 3 4 5 6Voltage [V]

Pe

rfo

rma

nc

e [

Cd

/A o

r lm

/W]

0.01

0.1

1

10

100

1000

10000

Lu

min

an

ce

de

ns

ity

[C

d/m

²]

Luminance Efficiency [Cd/A]

Power Efficiency [lm/W]

Luminance density [Cd/m²]

16 lm/W

13.5 Cd/A

"... high brightness at low operating voltage"

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Light Emitting Polymers have a lot of advantages … Low energy consumption Useful for large area lighting Simple to use technology Permits flexible lighting and displays A technology for the future

disadvantages: Non-uniform color displays

Manufacturing process is costly

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PLED Vs. LED LED is made from inorganic emitting material like

silicon, III-IV semiconductors, but PLED is made

from inorganic material like polymers.

LED is used as narrow field of application, but

PLED is used as very wide application field.

PLED gives more benefits than LED.

PLED Vs. LCD Full-color OLED-based displays will have replaced

active matrix LCDs as the market dominant display

technology by around 2010.

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LEP technology combines simple solid-state construction, low drive voltage and high efficiency OLEDs with large area pattern ability and the possibility of flexible substrates.

LEP technology will initially be used to extend the performance of current displays in mobile communication, computers and consumer electronics.

The fast switching speed of LEP would allow small, high-resolution screens to be constructed

CONCLUSION

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THANK YOU !!!

POLYMER LED

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