Organic Light Emitting DiodesMaterial Science
Stephen Clemmet CEng MSc BEng MIET
Oxford - Great Britain
Topics
Organic Light Emitting Diode Devices
1. Overview of OLED technology2. Fluid material science3. Lifetime and degradation
Ultraviolet Curing
4. UV-inkjet curing technology5. Material science6. Curing techniques7. Curing challenges
Technology Overview
Organic Light Emitting Diodes
OLED System
OLED Driver
Channels
PWM
Current
Battery
Device
EncapsulationUV
Cathode
ETL
EmissiveUV
HTL
MaskUV
Anode
Substrate
Organic Electronics Literature
Organic Electronics
Hagen Klauk
Wiley- VCHISBN 978-3-527-31264-1£126 / €146
Organic Electronics Literature
Organic Light-Emitting Devices
Joseph Shinar
SpringerISBN 0-387-95343-4£87 / €100
Material Science
Lifetime
Oxygen Pin holesTemperature Water vapour
OLED Structure
Encapsulation
Power
Mask Mask
Hole Transport
Emissive
Electron Transport
Cathode
Substrate
Anode
Light
Substrates
Substrate
Material Malleability Thicknessµm
WVTRml/m2/24hr
O2TRcm3/m2/24hr
Glass Rigid 1110 - -
PET Flexible 160 1.6 1.5
PET = Polyethylene terephthalateWVTR = Water vapour transmission rateO2TR = Oxygen transmission rate
www.norner.no/bcalc/model/wvtr/film
Anode Materials
Anode
Parameter ITO on glass ITO on PET PANI PW
Malleability Rigid Flexible Flexible Flexible
Resistivity Ω/m2 10 / 45 / 85 60 / 200 / 300 4 <0.1
ITO = Indium tin oxidePANI = PolyanilinePW = Printed wire
Printed Wire
Track width = 0.05mTrack pitch = 0.5mmResistivity ≤ 0.1 Ω/m2
Mask Materials
Mask
Deposition Colours Curing Performance
UV-inkjet CYMK / BW Seconds Excellent
Screen-print CYMK / BW minutes Excellent
UV = Ultraviolet
Hole Transport Layer
Hole Transport
Material Deposition Colour ResistivityΩ/m2
PEDOT:PSS Spin-coat Dark blue 500
PEDOT:PSS Inkjet Dark blue 75-120
PEDOT:PSS = Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)
Emissive Layer
Emissive
Material Deposition Solvent Colour Performance
Ruthenium complex Spin-coat Acetonitrile Red Good
Ruthenium complex Inkjet DMF Red Good
DMF = N,N-Dimethylformamide
Polymertronics’ Red Diamond 620s Deposition
Inkjet on ITO
Red Diamond Emission Spectra
Electron Transport Materials
Electron Transport
Material Solvent Colour Performance
Alq3 Chloroform Green Good
PBD Toluene Clear Fair
Butyl-PBD Toluene Clear Fair
Alq3 = Tris-(8-hydroxyquinoline)aluminumPBD = 2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazoleButyl-PBD = 2-(4-tert-Butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazol
Material DepositionWork
FunctioneV
ResistivityΩm
TempºC Performance
Aluminium Sputter 4.08 2.7 x10-8 500 Excellent
Indium-Gallium Liquid 4.15 29.4 x10-8 16 Good (Lab)
Indium Foil Heat 4.12 8.4 x10-8 157 Fair
Silver Particles Liquid 4.26 1.2 x10-8 25 Fair
Gold Sputter 5.10 2.4 x10-8 500 Useless
Cathode Materials
Cathode
Indium-Gallium
Encapsulation Materials
Material Malleability Thicknessµm
WVTRml/m2/24hr
Glass Rigid 1100 -
PET Flexible 160 1.6
PEN Flexible 160 0.5
CA Flexible 110 77
PET = Polyethylene terephthalatePEN = Polyethylene nitrideCA = Cellulose Acetate
Encapsulation
UV-Inkjet
UV-Inkjet
www.cyan-tec.com
Advantages of UV-Inkjet
Fast printing4s curing timeHigh durability
High dot-registrationInkjet on non-pourous surfaces
Print electronics with CYMK graphics
UV Bands
BAND Wavelength nm Curing Source
UVA 380-315 CYMK HgPb
UVB 315-280 - -
UVC 280-200 GMA HgFe
VUV 200-100 - -
HgPb = Mercury - LeadHgFe = Mercury – IronCYMK = Cyan, yellow, magenta, black colour inksGMA = Poly(tert-butyl methacrylate-co-glycidyl methacrylate)
400nm 700nm
Mercury-Lead Spectra
Mercury-Iron Spectra
Red Diamond 620 Emissive Layer
Emissive
Material Deposition Solvent Wavelengthnm Polymer Initiator
Ruthenium complex Inkjet DMF 260 GMA PDT
DMF = N,N-DimethylformamideGMA = Poly(tert-butyl methacrylate-co-glycidyl methacrylate)PDT = (4-Phenoxyphenyl)diphenylsulfonium triflate
Electron Scans
Organic Light Emitting DiodesMaterial Science
Stephen Clemmet CEng MSc BEng MIET
Oxford - Great Britain