this ppt is focused on led and its types

1. POLYMER
LED
ANAND ENGINEERING COLLEGE, AGRA
Presented By
DILIP MATHURIA
Roll No. 1100132003
Branch. EI
Submitted to -
Mr. Shobhit
Maheshwari
EI Department

2. INTRODUCTION
 Polymer LED (light-emitting diode)- sometimes
called light-emitting polymer or P-OLED 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.

3. PLED does not require additional elements such as
backlights, filters and polarizers.
PLED technology is very energy efficient.
 The main principle behind PLED technology is
electroluminescence.
Offers brighter, thinner, high contrast, flexible
displays.
INTRODUCTION (Cont..)

4. Brief History of Poly LED
The making of the first PLED is credited to the
Cavendish Laboratory of Cambridge University in
1989.
Polyphenylene vinylene (PPV) was found to emit
yellow green light when sandwiched between a pair
of electrodes. The initial device efficiencies were
very low .
PLEDs today have a number of intrinsic
advantages over liquid crystal devices.

5. A thin film of light Emitting Polymer put between two
electrodes will glow...
Light Emitting Polymer Device
+-
Metallic
Electrode
Thin Plastic
Film of PLED
Transparent
Electrode
Substrate
Emitted light

6. Device Structure
A transparent electrode with a large work
function.
Indium Tin Oxide (ITO) is commonly used.
A layer of PLED material less than 100nm thick.
PPV is commonly used.
A metallic electrode with a low work function,
typically calcium.

7. Working of PLEDs
 An amorphous film of the PLED material is
sandwiched between two electrodes forming the
anode and cathode on a substrate.
 Electronic charges are injected into the polymer
from the electrodes: electrons from the cathode, and
'holes' from the anode.
 The electrons and holes 'capture each other' through
electrostatic interaction.
 Radiative recombination of electron and hole
generates light
 The wavelength of this emitted light depends on the
band gap of the polymer used.

8. •If voltage is applied, positive
charge carriers
move into the anode,
negative charge carriers into
the cathode!
•Positive and negative charge carriers
combine and generate an neutral exited
state. This exited state decays and
generates Visible light
Visible Light

9. OLED Technology
Organic LED

10. OLEDs are solid state devices composed of thin
films of organic molecules that is100 to 500
nanometres thick.
They emits light with the application of electricity.
Band gap ranges from 2.2 to 2.8 ev.
They are self emitting.
They are made from carbon and hydrogen.
What is an OLED?

11. Structure of OLED
 Substrate.
 Anode.
 Organic layer.
-Conductive layer (Hole Transport Layer).
made up of polyaniline or metal-phthalocyanine.
-Emissive layer( Electron Transport Layer).
made up of polyfluorene or metal chelates.
 Cathode.

12. Structure of OLED (Figue)

13. Working Principle
A voltage is applied across the anode and cathode.
Current flows from cathode to anode through the
organic layers.
Electrons flow to emissive layer from the cathode.
Electrons are removed from conductive layer leaving
holes.
Holes jump into emissive layer .
Electron and hole combine and light emitted.

14. Working Principle(figure)

15. Types of OLED
Six types of OLEDs
Passive matrix OLED (PMOLED).
Active matrix OLED (AMOLED).
Transparent OLED (TOLED).
Top emitting OLED.
Flexible OLED (FOLED).
White OLED (WOLED).

16. Active Matrix OLED (AMOLED)

17. Applications:
 Automobile light system without bulbs.
 Thin and light weight displays for
portable electronics.
 Light weight wrist watches.
 All colours possible.
 All shapes and non-planar displays
possible.
 A technology for the future.
 Mobile phones with OLED screens.

18. OLED screen TV

19. OLED screen mobile Phones
(AMOLED)

20. OLED screen
Laptops

21. Advantages:
 Low energy consumption.
 Life time of more than 30,000 Hours.
 Thinner, Lighter and more flexible.
 Very high brightness and contrast.
 Can be made to larger sizes.
 High resolution.
 Perfect display from all angles.

22. Disadvantages:
 Non-uniform color Displays.
 Manufacturing Process is Costly.
 Lifespan.
 Water damage.
 Voltage drop may affect the
performance.

23. CONCLUSION
• The production of the PolyLED has fewer
restrictions in terms of size.
• The PolyLED has three major advantages over its
silicon counterpart: it has a high contrast, a high
brightness and requires much less power.
• Organic Light Emitting Diodes are evolving as the
next generation displays.

24. References:
http://cnx.org/content/m25670/latest/
http://www.cdtltd.co.uk/technology/introduction-to-p-
oleds/
http://en.wikipedia.org/wiki/Light-
emitting_diode
http://en.wikipedia.org/wiki/OLED
http://www.nbcnews.com/tech/tech-news
http://www.oled-info.com/p-oled
http://en.wikipedia.org/wiki/Thin-film_transistor

25. THANK YOU !!!