ORGANIC LIGHT EMITTING DIODE

BY

RAJESH PANIGRAHI

REGN NO:- 14304018

DEPT. OF ELECTRONICS ENGG.

• Organic Light Emitting Diode(OLED).

• Emerging Technology for displays in devices.

• Main principle behind OLED technology is

electroluminescence.

• Offers brighter, thinner, high contrast, flexible

displays.

INTRODUCTION

Contd..

• 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.

HISTORY• The discovery of the electroluminescence property in organic

materials in 1950s is considered to be the stepping stone of

OLED

• 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.

Contd.. In 2001, Sony developed world’s largest full colour 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.

Structure of OLED

Architecture of OLED• Substrate (clear plastic, glass, foil) - The substrate supports the

OLED. • Anode (transparent) - The anode removes electrons (adds electron

"holes") when a current flows through the device.• Organic layer:

o Conducting layer - This layer is made of organic plastic molecules that transport "holes" from the anode.

o Emissive layer - This layer is made of organic plastic molecules that transport electrons from the cathode; this is where light is made.

•  Cathode (may or may not be transparent depending on the type of OLED) - The cathode injects electrons when a current flows through the device.

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.

Working Principle (Diagram)

OLED DEVICE OPERATION

Transparent substrate

Anode(ITO)

Conductive layer

Emissive layer

Cathode

LUMO

LUMO

HOMO

HOMO

eˉeˉ

h+

h+h+

Light

Types of OLEDs1.Passive OLEDs

• The organic layer is between strips of cathode and anode that run perpendicular

• The intersections form the pixels

•  Easy to make• Use more power• Best for small screens

Contd..

2.Active OLEDs

• Full layers of cathode and anode

•  Anode over lays a thin film transistor (TFT)

• Requires less power• Higher refresh rates• Suitable for large

screens

Contd..3.Transparent OLED

Contd..4.Top Emitting OLED

Contd..5. FLEXIBLE OLED

FLEXIBLE OLED It incorporates a flexible plastic substrate on which

organic semiconductor is deposited. Works on the principle of electroluminescence. Generally OLEDS are fabricated on glass substrate

whereas flexible OLEDS are fabricated using flexible plastic such as polyethylene terephthalate.

Contd..

Flexible OLED devices can be fabricated by deposition of the organic layer onto the substrate using a method derived from inkjet printing, allowing the inexpensive and roll-to-roll fabrication of printed electronics.

Flexible OLEDs may be used in the production of rollable displays, electronic paper, or bendable displays which can be integrated into clothing, wallpaper or other curved surfaces.

OLED vs. LCD OLED• Greater view angle.• High contrast.• Faster response time.• Do not require

backlighting.• Temperature(~50°C –

80°C).

LCD

• Limited view angle.

• Low contrast.

• Slow response time.

• Require backlighting.

• Temperature(~0°C-100°C).

OLED vs. LED OLED• Picture clarity is good.

• High contrast.• Faster response time.• Do not require backlighting• Colour space is good.• Viewing angles are more(170)• Expensive

LED

• Picture clarity is comparatively bad.

• Low contrast.

• Slow response time.

• Require backlighting

• Colour space is bad

• Viewing angles are less

• Cheap

Current Research for OLEDs• Manufacturers focusing on finding

a cheap way to produceo "Roll-to-Roll" Manufacturing

• Increasing efficiency of blue luminance 

        • Boosting overall lifespan

Advantages of OLED

• Thinner, lighter and more flexible.

• Do not require backlighting like LCDs.

• Can be made to larger sizes.

• Large fields of view, about 170 degrees.

• Faster response time.

• Brighter.

• High resolution, <5μm pixel size.

Disadvantages of OLED

• Expensive.

• Lifespan .

• Water damage.

• Colour balance issues.

Applications of OLEDs TVs Cell Phone screens Computer Screens Keyboards (Optimus Maximus) Lights Portable Divice displays

OLED Televisions OLED TELEVISIONS

• Released XEL-1 in February 2009. • First OLED TV sold in stores.• 11'' screen, 3mm thin• $2,500 MSRP • Weighs approximately 1.9 kg • Wide 178 degree viewing angle• 1,000,000:1 Contrast ratio

Future Uses for OLEDLIGHTING:

Flexible / bendable lighting Wallpaper lighting defining new ways to light a space Transparent lighting doubles as a window

Contd..Cell Phones:

Nokia 888

REFERENCES• http://impnerd.com/the-history-and-future-of-oled• http://en.wikipedia.org/wiki/Organic_light-emitting_diode• http://www.oled-research.com/oleds/oleds-history.html• http://www.voidspace.org.uk/technology/

top_ten_phone_techs.shtml#keep-your-eye-on-flexible-displays-coming-soon

• http://www.pocket-lint.com/news/news.phtml/23150/24174/samsung-say-oled-not-ready.phtml

• http://www.cepro.com/article/study_future_bright_for_oled_lighting_market/

• http://www.technologyreview.com/energy/21116/page1/ • http://optics.org/cws/article/industry/37032 • http://jalopnik.com/5154953/samsung-transparent-oled-display-

pitched-as-automotive-hud