Andrew Sanders Fawzi Salama John P Handrigan 12022010 Outline Introduction How OLEDs work Materials Fabrication Techniques Recent Developments Conclusions 2 Introduction 3 ID: 476082
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Organic Light Emitting Diodes
Andrew Sanders, Fawzi Salama, John P. Handrigan
12/02/2010Slide2
Outline
IntroductionHow OLEDs work?MaterialsFabrication TechniquesRecent DevelopmentsConclusions
2Slide3
Introduction
3Slide4
Applications
http://en.wikipedia.org/wiki/File:OLED_EarlyProduct.JPG
http://www.newlaunches.com/entry_images/1107/14/sony_xel2-thumb-450x337.jpg
http://www.hitech-projects.com/euprojects/olla/downloads/pictures/olla_4generations.jpg
4Slide5
Advantages
Low power consumptionFlexible displays (with polymer layer)High Contrast (1,000,000:1)Thin Displays (3mm)Thin organic Layer (100 -150 nm)
5Slide6
History
Commercialization of inorganic LEDs in 1960’sOLEDs using small moleculesTang and Van Sylke from Kodak (1987)Discovery of electroluminescence from polymers J. H. Burroughes et al. (1990) at University of Cambridge
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How OLEDs WorkOrganic
SemiconductivitySMALL MOLECULE TYPE
POLYMER TYPE
Aluminum oxinate
Polyphenylene vinylene
http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=24868131
http://upload.wikimedia.org/wikipedia/commons/9/94/Polyphenylene_vinylene.png
7Slide8
How OLEDs WorkStructure
Electrons (-)
Electron-holes (+)
http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=19353440
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HOMO
(valence band)
Electron Holes (+)
Electrons (-)
Emissive Layer
Δ
E=h/ (
λ
c)
LUMO
(Conduction band)
9
How OLEDs Work
ElectroluminescenceSlide10
Configuration
SubstrateGlass, PETAnodeITO, PolyanilineCathodeCa, Mg-Ag, Al-LiHTLETL
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http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=19353440
Anode
Substrate
HTL
Cathode
EML
ETLSlide11
EML Materials
11PropertiesSemi-conductorRadiative recombination dominates due to large energy level3 basic colors
2 typesSmall MoleculesPolymersSlide12
Photo Emitting Materials
Small MoleculesGreen: Alq3Blue: DistyrylarylenesRed: RubrenePolymersGreen: PPV
Blue: PPP’s, PFO’sRed: PT’s, P3ATs12
Rubrene
Alq3
Distyrylarylene
PPV
PPP
PTSlide13
Fabrication Techniques
13Wet TechniquesInkjet PrintingDry TechniqueVacuum Thermal Evaporation
Organic Vapour Phase DepositionSlide14
Fabrication Techniques:
Inkjet Printing14Advantages
Solution for large area depositionDisadvantagesDeposited film is non-uniformSlide15
Fabrication Techniques:
Vacuum Thermal Evaporation15Advantages
High film uniformityVacuum equipment is availableDisadvantagesOrganic build up on chamber wallsExpensiveSlide16
Fabrication Techniques:
Organic Vapour Phase Deposition16Slide17
Fabrication Techniques:
Organic Vapour Phase Deposition17Advantages
High uniformityReduced organic material consumptionDoes not require high-vacuum conditionsDisadvantagesExpensive equipmentSlide18
Market
18Slide19
Current Research
Phosphorescent materialsDevice lifetimeApplication to solar cells19Slide20
Conclusions
Young technologyEnormous progress on materials and fabrication techniquesGrowing technology for electronics displayWith lower costs, the best technology to adopt20Slide21
Questions?Thank you