Silver Nanowire Electrodes: Enabling Flexible, Transparent and Cost Effective OLED Lighting
DOE SSL R&D Workshop January 27, 2015
Rahul Gupta Senior Director, Business Development [email protected]
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Cambrios ClearOhm® Transparent Conductor: Single Crystal Silver Nanowire
Highly ConducKng
Extremely Transparent
Flexible & Formable
Low Temperature SoluKon Process
Available in Large
Volumes
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Lenovo Flex 20 20” AIO
15” POS Monitor
LG ET83 23”
Monitor
BenQ F5
Lenovo A540 23” AIO
Medias X on NTT docomo
Karbonn A29 (India)
Advan S5G 5” and 5.7”
Lenovo A740 27” AIO
Tablets & eReaders Smartphones
POS Monitors LG ET63
23” Monitor
LG V325 23” AIO
HP 23” AIO
Fuhu Nabi 24” Bigtab
Fuhu Nabi 20” Bigtab
Monitors and All-‐In-‐One PC’s
Numerous ClearOhm® Touch Sensor Products In The Market
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Robust Supply Chain In Place
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Transparent Conductor Requirements For OLED Lighting
• Performance – Current spreading to ensure large area with
uniform emission, flexible, transparent – Efficiency and Lifetime – Compatible with light extraction or
improves light extraction • Manufacturability
– Processable – Scalability of process
• Cost structure to enable cost effective OLED lighting
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Options For Transparent Electrodes ITO NW Metal Grid FTO/AZO
Pros • Well established incumbent
• Low cost soluKon process
• Low capex • Scalable • Flexible
• High conducKvity (<1-‐50 ohms/sq)
• Flexible
• 10-‐20 ohms/sq • CompaKb le w i th
glass producKon
Challenges • Limited conducKvity, especially on plasKc
• Bri\le/not flexible
• High CapEx • Expensive
vacuum process
• 5 ohms/sq with >90% transmission
• OpKcally visible • Large openings è
charge spreading • High thickness è
needs dielectric/ planarizaKon
• LifeKme issues: needs passivaKon
• Cost compeKKve only at very high volumes (inline with float glass process)
• Bri\le/not flexible • Roughness • High CapEx • Expensive vacuum
process
70#Ω/�# 9#Ω/�#
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Low Sheet Resistance With High Transmission: Enables Metal Grid Free Large OLED Tiles
Spin coaKng on glass, glass as reference (glass = 100%)
10cm x 10 cm ClearOhm OLED Tile
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Luminance Uniformity : Enabling 20cm x20 cm Tiles Without Metal Grids Variables: Efficiency, Sheet resistance, 2 vs 4 sided contact
-‐ Good luminance uniformity can be achieved with 5-‐10 Ω/□
Luminance = 3000nits
min
max
min
max
1L
LL
LUniformity
+−−
=
Cathode contact
Cathode contact
Anode contact
2 sided anode contact
4 sided anode contact
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Similar Efficiency and Lifetime as ITO
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CAPACITY, SCALABILITY AND COST
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Cambrios Has Capacity To Meet Growing Demand
2013 22,000 L/year
2014 175,000 L/year
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Low Cost Solution Process: Roll-To-Roll Or Sheet Glass Or Plastic Substrates
R2R producKon coater: 3-‐6 Million m2/year capacity Investment $~2 Million
ProducKon sheet slit coater (G4.5) 0.5-‐1 Million m2/year capacity Investment $~1.5 Million
Cambrios 300mm pilot coater; ~$300k
Low Cost Pilot
Low Cost ProducKon
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Printed Silver Nanowire Electrodes Eliminate Cost Of Patterning
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Large Area OLED Tiles With Printed Silver Nanowire Electrodes
Newly developed printed transparent electrode can replace ITO
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Cost Savings by using ClearOhm® Electrodes for OLED/PV • Solution process for coating vs vacuum process
for ITO: Depreciation <$0.1-0.6/m2 vs ~$9/m2
• Printing to eliminate expensive photo patterning – Photo-patterning costs ~15-20/m2 at G4.5 – Or use low cost laser patterning or screen printable
etchants
• Metal Grid Free OLED Lighting Tiles – Eliminates metal grid – Eliminates bank structures/passivation layers
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Improved Process Window For Higher Yields Scalability to Gen 5/8 Sheets or R2R
• No coherent reflection from Nanowires è no micro-cavity effect
• Color does not change with thickness of stack – Wider process Window even for Gen 5 – No need to bin products based on location on substrate
~3% Change in stack thickness Large change in color with ITO Anode No change in color with ClearOhm Anode
10 nm change in stack thickness 10 nm change in stack thickness
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Controlled by OLED Maker
Controlled by Substrate maker
Integrated Substrates With Nanowires
Substrate
External light extracKon film
Index/sca\ering/planarizing layers
Anode
HIL HTL
EML
ETL
Cathode Top encapsulaKon
• Low temperature process for nanowires • Opens up choices for low cost planarizaKon layers on top of
sca\ering/high index layers • Can combine sca\ering/high index materials with nanowires
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Controlled by OLED Maker
Controlled by Substrate maker
Silver Nanowires Allow OLED Makers To Optimize Internal Light Extraction
Substrate
External light extracKon film
Index/sca\ering/planarizing layer
Anode
HIL HTL
EML
ETL
Cathode Top encapsulaKon
• Allows matching of light extracKon layers to OLED stack to opKmize performance
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ENABLING TRANSPARENT FLEXIBLE & FORMABLE PRODUCTS
Clothes
Furniture
Walls/Glass/Buildings
Automobiles
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ClearOhm® Material: Excellent Performance As Top Transparent Electrode
Acknowledgements: Matthew White, Markus Scharber, Lucia Leonat, Michael Drack, Martin Kaltenbrunner, Siegfried Bauer, and Serdar Sariciftci
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Fully printed Transparent OLED
ON state
OFF state
ZnO
PEDOT:PSS ITO-‐PET
SPW-‐111
ClearOhm®
1cm2
450 500 550 600 650 700 7500
20
40
60
80
100
TOLED
Tran
smis
sion
[%]
Wavelength [nm]This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 314233 - http://inlight-project.eu/
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Flexible and Bendable: passes 100,000 cycles at 3mm bend radius
Data Courtesy Nissha PrinKng Co.
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Flexible Transparent OPV Modules with Silver Nanowires
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Summary
• ClearOhm adopted as the transparent conductor of choice by leading touch panel makers
• ClearOhm enables cost effective production of OLED’s – Large size tiles without metal grids eliminates process steps
– Printing eliminates etching
• Improved performance and scalability for manufacting – Wider process window enables scaling to G5/8 or R2R production
– Control and design freedom to improve light extraction
• ClearOhm enables key differentiating features for OLED lighting – Flexible, formable and transparent devices
• Available in large volumes to support production
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Thank You
Cambrios ConfidenKal
