The document discusses organic light emitting diodes (OLEDs), including their history, structure, operation, types, advantages, and comparison to other display technologies. OLEDs were first developed in 1987 and have since been used in many commercial displays. They consist of thin organic layers between an anode and cathode that emit light when electricity is applied. Multi-layer OLEDs use additional layers like hole and electron transport layers to improve efficiency. Key advantages of OLEDs are their brightness, thinness, viewing angles, response time and power efficiency.

1. Organic Light Emitting Diode
(OLED)
Presented by:
Muhammad Umar 2012-MS-EE-50
Waqar Mahboob 2012-MS-EE-96
Ahmed Bilal Hussain 2012-ME-EE-14
Iayan Khalid 2012-MS-EE-20

2. Contents
 Introduction
 History
 Structure of OLED
 How OLED works?
 Types of OLEDs
 Advantages and disadvantages
 Comparison
 Conclusion
 References
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3. Introduction
 Emerging Technology for displays in devices.
 Main principle behind OLED technology is
electroluminescence. [1]
 Offers brighter, thinner, high contrast, flexible displays.
 OLEDs are solid state devices composed of thin films of
organic molecules that is 100 to 500 nanometres thick.
 They emits light with the application of electricity.
 They doesn’t require any backlight. i.e., they are self
emitting.
 They are made from carbon and hydrogen.
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4. Cont..
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5. History
 The first OLED device was developed by Eastman Kodak in
1987.
 In 1996, pioneer produces the world’s first commercial
PMOLED.
 In 2000, many companies like Motorola, LG etc developed
various displays.
 In 2001, Sony developed world’s largest fullcolor OLED.
 In 2002, approximately 3.5 million passive matrix OLED sub-
displays were sold, and over 10 million were sold in 2003.
 In 2010 and 2011, many companies announced AMOLED
displays.
 Many developments had take place in the year 2012 for5

6. OLED Structure Diagram
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7. Structure of OLED
 Substrate( made up of Plastic or Glass)
 Anode. (made up of ITO)
 Organic Layer.
 Cathode. (made up of oxides of Calcium,
Aluminium or Magnesium)
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8. Single Layer and Multilayer
OLEDs
 Single Layer:
◦ Contains only one organic layer between two
electrodes.
◦ Having Low Operation Efficiency.
 Multi-Layer:
◦ Two or more layers are between electrodes
depending on the application.
◦ Two most frequently used layers are HTL and ETL.
◦ Conductive layer (Hole Transport Layer).
made up of polyaniline or metal-phthalocyanine.
◦ Emissive layer( Electron Transport Layer).
made up of polyfluorene or metal chelates.
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9. Working
 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
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10. OLED device operation
Transparent
substrate
Anode
(ITO)
Conductive
layer
Emissive
layer
Cathode
LUMO
LUMO
HOMO
HOMO
eˉ
eˉ
h+
h+
h+
10
Energy Diagram

11. Types of OLED
Six types of OLEDs [3]
 Passive matrix OLED(PMOLED).
 Active matrix OLED(AMOLED).
 Transparent OLED(TOLED).
 Top emitting OLED.
 Flexible OLED(FOLED).
 White OLED(WOLED).
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12. Passive Matrix OLED
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13. Active Matrix OLED
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14. Transparent OLED
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15. Top Emitting OLED
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16. Flexible OLED
 Human hair is 200x the thickness of the OLED
layers. 16

17. Advantages[2]
 Lower Cost in the future.
 Light weight & flexible plastic substrates.
 Wider viewing angles.(178°)
 Improved brightness (25% more than LCD)
 Better power efficiency (40% less than
LCD)
 Response time (<0.01 ms)
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18. Disadvantages[2]
 Current cost
 Life Span
 Colour Balance Issue
 Efficiency of Blue OLEDs
 Water Damage
 Outdoor Performance
 Power consumption for white display
 UV sensitivity.
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19. Comparison between LCD,
Plasma and OLED[2]
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20. Conclusion
 OLED contains stunning picture qualities and it
open a new era in display devices.
 Use of proper encapsulation to prevent device
from water.
 Outdoor performance can be increase by using
circular polarizer or anti-reflective coating on
cathode.
 Singlet excitons will migrate with an average
diffusion length of about 20 nm followed by a
radiative or irradiative decay in Single Layer
OLED. [4]
 Using Multilayer OLEDs migration and decay of
singlet excitons are also restricted resulting in
drastically improved luminous and quantum
efficiencies compared to simple single layer
devices [5] 20

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22. References
[2] Srećko Kunić, Zoran Šego, OLED Technology and Displays,
54th International Symposium ELMAR-2012.
[4] C.W. Tang, S. A. VanSlyke, C. H. Chen: Electroluminescence of
doped organic thin films, J. Appl. Phys., 65, 3610–3616, 1989.
[5] Dirk Ammermann, Achim Böhler, Wolfgang Kowalsky, Multilayer
Organic Light Emitting Diodes for Flat Panel Displays, Annual
report 1995, Institut für Hochfrequenztechnik, TU Braunschweig
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