Polymer Light Emitting Diode

POLYMER LIGHT EMITTING DIODE

Biswajit AcharyaM.Tech,AEIE,1st YearHeritage Institute of Technology.

PRESENTS..

OUTLINE…Introduction to LED, its classes,

polymers and LEP

Need to go for P-LEDs

Structure and operation of the P-LED

Fabrication Steps of P-LED

Various characteristics of P-LEDs

P-LED Manufacturers, Applications and Challenges.

Conclusion and References..

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POLYMER…A chemical compound or mixture of compounds (usually hydrocarbons) consisting essentially of repeating structural units called monomers formed by polymerization.

Polythene

Poly-vinyl chloride(PVC)

Poly-Phenylenevinylene(PPV)


LIGHT EMITTING DIODES..

LED

InorganicLED

OrganicLED

(OLED)

Small MoleculesOLED

(SMOLED)

PolymerOLED

(PLED)


LIGHT EMITTING POLYMERConjugated polymers are organic semiconductors, the semiconducting behavior is associated with the “π” molecular orbitals, delocalized along the polymer chain. The injection of an electron and a hole on the conjugated chain can lead to a self-localized excited state which can then decay radiatively.


LIGHT EMITTING POLYMERS…HOW IT ALL BEGAN

A light emitting polymer is an electro-luminescent plastic. The molecules of this plastic emit light when an electric field is applied. The first observations of electroluminescence in organic materials were in the early 1950s by André Bernanose, in France. Electroluminescence from polymer films was first observed by Roger Partridge at the National Physical Laboratory in the United Kingdom in 1983.The first diode device was reported by Ching W. Tang and Steven Van Slyke in 1987.J. H. Burroughes reported a high efficiency green light-emitting polymer based device in 1990.


7

Just Imagine

Viewing a HD TV that is 80 inches wide and less than a quarter-inch thick, consumes less power than most TVs on the market today and can be rolled up when not in use.!!!

What if you could have a "heads up" display in your car.!!!

How about a display monitor built into your clothing…..!!!

Polymer Light Emitting Diode 04/10/2023

WHY P-LEDS ??? Lightweight and flexible, so

they can be simply used to make thin films.

Extraordinary resolution which provide high quality imaging;

Can be seen from any angle without the loss of information;

Enable more energy efficiency; Consume less power; They can be used to make

flexible displays; They offer high brightness at

low drive voltages; They ensure glare-free

viewing;


P-LED STRUCTURE…

9

Polymer LED


P-LED STRUCTURE- DETAILED

A transparent anode with a large work function. Generally Indium Tin Oxide (ITO) is used.A conducting polymer layer which transports and injects holes into the active layer.A thin light emitting polymer layer less than 100nm thick.A metallic cathode with a low work function, such as Aluminium.A substrate usually made up of transparent plastic to support the P-LED.


HOW DOES THE P-LED WORK???


P-LED FABRICATION STEPS..

The substrate is cleaned and kept in dust free area.

The electrode contacts are incorporated by Vacuum

Evaporation process.

Testing

The multilayer deposition of the polymer takes place through the Spin Coating or Organic Vapor Phase Deposition (OVPD) method.


P-LED FABRICATION - CONTINUED

Spin Coating

Evaporation Deposition


Organic Vapor Phase Deposition

P-LED – VOLTAGE/LUMINANCE BEHAVIOR


P-LED – VOLTAGE/EFFICIENCY BEHAVIOR


P-LED – LUMINANCE/EFFICIENCY BEHAVIOR


P-LED-LEADING MANUFACTURERS..


P-LED- INDUSTRIAL APPLICATIONS…

22%

19%16%12%

8%

6%

4%12%

Lighting Imaging Technology DevelopersDisplay Manufacturers Materials AutomotiveAcademic Other


P-LED – CONSUMER APPLICATIONS…


PERFORMANCE COMPARISON…

20

PLED LCD


Fast Response Time Wide Viewing Angle

PLED LCD

Better Contrast Ratio PLED LCD

CHALLENGES…

Limited lifetime of the organic materials. "After 1,000 hours: the blue luminance gets degraded by 12%, the red by 7% and the green by 8%.”

Color Balance. Water Damage. More power is consumed when used against white

background. The metallic cathode in an OLED acts as a mirror, with

reflectance approaching 80%, leading to poor readability in bright ambient light such as outdoors.


CONCLUSION

The P-LED technology, though is used in several fields, but it is still in the budding stage. Its shortcomings need to be specially attended, especially the efficiency of the blue color. In days to come, the use of this technology will just multiply itself to foster the growth of the world of light.


Cheape

r way to

produc

e !!!

Boosting

Overall Lifespan….

REFERENCES..

http://www.ewh.ieee.org/soc/cpmt/presentations/cpmt0401a.pdf

http://www.cdtltd.co.uk/technology/introduction-to-p-oleds/ http://www.nature.com/physics/looking-back/burroughes/index

.html https://www.rochester.edu/news/show.php?id=829 http://electronics.howstuffworks.com/oled.htm Research journal on ADVANCED MATERIALS by C.W. Tang Research journal on LIGHT EMITTING POLYMERS by Dmitrii

F. Perepichka, Igor F. Perepichka, Hong Meng, Fred Wudl. Research journal on POLYMER LEDs by Christian Wenning. Research journal on PROGRESS IN POLYMER OLED

EFFICIENCY by M. Roberts, N. Akino, K. Asada, P. Benzie, H. Hamamatsu, M. Hatcher, S. King, E. Snedden, A. Stevens, S. Tanaka, J. Toner, R. Wilson, W.Young, T. Yamada 23Polymer Light Emitting Diode 04/10/2023



http://www.cdtltd.co.uk/technology/introduction-to-p-oleds/

http://www.cdtltd.co.uk/technology/introduction-to-p-oleds/

http://www.nature.com/physics/looking-back/burroughes/index.html

http://www.nature.com/physics/looking-back/burroughes/index.html

https://www.rochester.edu/news/show.php?id=829

Engineering

Polymer Light Emitting Diode