ultra-high barrier plastic - - get a free blog here

Ultra-high Barrier PlasticMSE5420 Flexible ElectronicsMartin Yan, GE Global Research

Outline

• Introduction to plastic substrate and need for barrier

•Barrier technologies

•WVTR measurement technologies

•Summary

2 /September 30th, 2008


Source: Displaybank’s presentation on 2007 Flexible Display & Microelectronics Conference

Evolution of Display Technology


OLED Technology

Cathode

n-layer

p-layer

Anode

Light

Sony XEL-1 11” OLED TV

DZ7086 OLED watch by Diesel

iRiver SPINN A/V Player

Nokia Prism Mobile Phone

Kodak EasyShare LS633 Camera


Flexible OLED Display

Source: UDC presentation on 2007 Flexible Display & Microelectronics Conference


Replace Glass with Plastic Substrate

NOW

Glass Substrate

Plastic Advantages

• Rugged.• Thinner.• Lighter.• Enable flexible display.• Enable R2R processing.

FUTURE

“Roll-Up Displays”

Plastic Film Substrate

Energy Consumption for Lighting: Year 200122% of the total electricity generated in the U.S. was used for lighting!

Total U.S. Primary Energy Consumption for Lighting by Sector

Lighting Energy Consumption by Sector & Source

Source: U.S. Lighting Market Characterization Volume I:


Need to replace incandescent with more efficient light technology!


Organic Electronics (OE) Advanced Technology Program at GE Global Research

Technologies:

Flexible substrate

Transparent contact

Metal contactV Organic Active Layers

“Newspaper-Like”Roll-to-Roll Fabrication

V• OLED Devices• Low Cost Manufacturing• High Barrier Substrate

High barrier substrate enables R2R OLED manufacturing.


OLED Offers Novel FeaturesMechanical Flexibility Thin and Light Transparent

Color Tunability


Source: Polymer Vision’s presentation on 5th Flexible Display and Microelectronics Conference

Source: UDC’s presentation on 5th Flexible Display and Microelectronics Conference

UDC’s Flexible Display Concept Polymer Vision’s Flexible Display Concept

GE’s Flexible Lighting Concept

Flexible OLED Product Concepts

Source: Best Life Magazine – February 2006


Opportunity for Plastic Substrate

•Flex.Display- OLED- LCD

•Digital Paper- E-paper- Postage

•Lighting- General lighting- Back lighting

•Solar Cell (PV)- Thin Film PV

Barrier Plastic Film

Maj

or P

laye

rs

Challenges for Flexible OLED SubstrateThe Problem

OLED

Polymeric substrate

Transparent electrode

H2O O2Commercial available polymeric substrate


Transparent ConductorMoisture/Oxygen Permeability

Hole InjectorLight Emitting Polymer

Metal Cathode

Ultra High Barrier

Ultra High Barrier

Transparent Anode

Moisture OxygenLow Temp.

PlasticHigh Temp.

Polycarbonate

Low Conductivity,Low Transmission

Anode

High Conductivity,High Transmission

Anode

Thermo-mechanical stability Optical Transmission

CTE Reduction / Stress Balance

CTE Reduction / Stress Balance

High CTE Plastic

H2Olow 10-6 g/m2/day

O2< 10-3 cc/m2/day


< 40 Ohm/ sq> 90 %T

Shrinkage< 20 ppm/hr @150°CBendingdiameter <=1”Adhesion≥ 4B

Light Emitting PolymerMetal Cathode

Ultra High Barrier

Ultra High Barrier

Transparent AnodeHole Injector

Substrate Requirement- Key Properties

> 80 %T

Barrier Substrate Development at GE Global Research

Plastic Substrate

Film

Ultra-high Barrier Coating

Chemical Resistant Coating

Transparent Conductor

Coating

Technology Development at GE

Enable

Integrated Plastic OLED Substrate


Chem resist layer

High heat polycarbonate

Graded ultra high barrier

Chem resist layer


Outline




•Summary



Material Options for Transparent Hermetic Barrier

Moisture Permeability

Time to Reach 50% of Outside RH

Ref. Traeger

Log

Thic

knes

s (m

eter

s)

OTR through Perfect SiO2 Barrier:

10nm ⇒ 10-24 cc/m2/day

10 nm continuous glass-like coatings would exceed the needs


Defect-Driven Moisture Permeation

1 10 100 1000

0.01

0.1

1

10

100

1000 Uncoated

OTR

@ 2

50 @ 1

00%

O2

SiNx Thickness (nm)

Detection limit

Non-Fickian Diffusion ~ 100 defects/mm2

20x

~1mm

Defect Imaging w/ Acetone

Barrier performance of single layer inorganic coating is defect limited


Ultra-high Barrier: Single Layer Approach–Uni. Of Colorado: Atomic Layer

Deposition of AlOx

–Dow Corning: Plasma Enhanced Chemical Vapor Deposition of SiOxCy

–Symmorphix: Sputtering of AlSixOy

Source: Symmorphix’s presentation on 4th

Flexible Display and Microelectronics Conference


Ultra-high Barrier: Multilayered Approach

Concept for Multilayer UHB

Tens of µm

Hundreds of nmOrganic coating

Inorganic coating

Defects

Source: VITEX’s presentation on 5th Flexible Display and Microelectronics Conference

Permeation Simulation: Multilayered Barrier


Assumptions: - 2 perfect barriers- each barrier has 1 defect- defects are offset/decoupled

Low

High

Fick’s Law:

Continuity:

DiffusionEquation:

0.1 1 10

0.1

1

ConductionLimitedRegime

Flux

Rat

io

Distance/Offset

Offset

Distance

Flux Ratio =Flux2 Layer System

Flux 1Barrier System

Work in this regime toachieve Ultra-High Barrier


Ultra-high Barrier: Graded Approach

XPS Spectrum of Graded UHBGE’s Graded Ultra High Barrier

Inorganic Organiczone

Continuous composition transition

Cross-sectional TEM of Graded UHB


Graded Ultra-high Barrier Plastic Film

Parallel plate PECVD High T Lexan® film

Low temperature PECVD process is compatible with plastic substrates

Base Film Surface Quality is Critical


Flexible OLED substrateThe Problem

OLED

Polymeric substrate


H2O O2Commercial available polymeric substrate

3,530 hrs at 23°C 40%RH

The Solution


OLED

Chem resist layer

High heat polycarbonate

Graded ultra high barrier

Chem resist layer


GE Barrier Substrate

H2O O212 mm

Proved that high barrier substrate is possible

Key USDC Specifications* GEGR Performance• Moisture Barrier 10-6 g/m2/day low 10-5~mid 10-6 (at 23°C 50 % RH)• Chemical Resistance acid, solvent, alkali Pass• Electrical Conductivity ≤40 Ω/Sq 40.3 Ω/Sq• Optical Transparency >80% 82 %• Mechanical Flexibility bend around 1” radius Pass.• Thermo-Mechanical Stability 2000C for 1hour Pass • Adhesion ≥4B 4B• Dimension stability <20 ppm/hr at 150°C 4 ppm/hr• Average surface roughness <5 nm 0.6 nm

15 cm square flexible OLED lighting Device on high heat polycarbonate substratewith graded UHB

GE’s Graded Barrier Plastic Performance

* Subset of complete USDC specification list


Outline




•Summary


WVTR measurement technologies

• Capacitive or Resistive (humidity sensor)

• Spectroscopy (mass spectroscopy, fluorescence quenching)

• Calcium degradation (optically or change in resistance)

• Radioactive (tritium)


Commercially Available Gas Permeation Measurement

H2O or O2H2O or O2

H2O or O2

Fourier transform Infrared (FTIR) Spectrometer

Source: PERMATRAN-W® Model 3/33 Operator’s Manual


Detection limit for H2O: 5×10-3 g/m2/day


Calcium Corrosion Test: GE’s Setups

Ca test @ 23°C / 50%RH

Ca Test @ 60°C 90% RH

Polycarbonate

EpoxyCa

Barrier Coating

Glass

525 hrs90% O.D.

Initial100% O.D.



General Atomics Tritium Test

Tritium Test: GAT’s Setup

Source: RALF DUNKEL, ROKO BUJAS, ANDRE KLEIN, AND VOLKER HORNDT, PROCEEDINGS OF THE IEEE, VOL. 93, NO. 8, AUGUST 2005, pg 1478-1482



OLED Device Test

Universal Display CorporationOLED Shelf Lifetime Test @ 60°C 85% RH

Glass/Glass control Device on GE sample

Glass/Glass control Device on GE sample

w/ desiccantw/o desiccant

Source: GE’s presentation on 4th Flexible Display and Microelectronics Conference

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