R2R Nanoimprint Process for Multilevel OLED substratewith Transparent Metal Mesh Conductor
W. Dennis Slafer
MicroContinuum, Inc.
57 Smith PlaceCambridge, MA USA 02138
Ruth Shinar, Joe Shinar, Rana Biswas
Microelectronics Research Center
Iowa State University
Ames, IA, USA 50011
Corresponding author: dennis.slafer@microcontinuum.com
ABSTRACT
Organic LEDs (OLEDs) on flexible substrates offer unique advantages for many lighting
applications due to their thinness, flexibility, and potentially low cost. However, the promiseof OLED technology in providing a “disruptive” advance for a large segment of the lighting
market cannot be realized until several technical and manufacturing barriers are overcome.
One structural component that would significantly improve this situation is an integrated
substrate capable of both extracting trapped light and providing an improved transparent
conductive layer to replace the current problematic anode layer, indium tin oxide (ITO). Key
to the success of this approach is the development of a roll-to-roll (R2R) manufacturing
technology that can cost-effectively produce this substrateThis presentation describes the design, development and fabrication of an integrated substrate
for OLED deposition that provides significantly improved device efficiency. The substrateenables extraction of much of the light (>50%) that is otherwise waveguided and lost in theorganic layers of the OLEDs, while also providing high electrical conductivity and improved
electrode uniformity for large area devices.
Nanoimprinting is used to form two discrete light extraction layers: an internal surface
comprising a periodically textured nanoarray for extraction of waveguide-trapped light basedon photonic simulation designs, and a microlens array (µLA) on the air-substrate surface toextract light trapped by total internal reflection.
Nanoimprinting is also used to form a novel and highly efficient metal nanomesh anode layerthat is embedded in and conformal with the internal periodic nanoarray. In addition toeliminating abrupt steps from the metal lines which cause shorting of the OLED layers, themesh geometry provides >99.5% transparency of the anode layer and features a secondary(field) conductor to produce a continuous, high conductivity transparent layer.

periodic
nanoarraycoatednanoarray

polymer
substrate
1) R2R nano patterning

500nm hex array2) R2R sputtering

metal mesh on nanoarray(donor)
4) wet de-scum + etching3) forming mesh mask(donor)
barrier coatedsubstrate (receiver)5) array/meshtransfer

imprinted µLA6) lamination

integrated substrate(ready for OLED
deposition & sealing)

Figure 1. R2R nanopatterning process for manufacturing integrated OLED substrate
metal foil
encapsulant
substrate + barrierµLAbarrierlayer

Figure 2. Cross-section of finished OLED on multi-level patterned substrate

References:
Hippola, C.; Kaudal R.; Manna, E.; Xiao, T.; Peer, A.; Biswas, R.; Slafer, W.D.; Trovato, T.;
Shinar, J.; Shinar, R.; “Enhanced Light Extraction from OLEDs Fabricated on Patterned
Plastic Substrates” Advanced Optical Materials 2018 6, (4) 1701244.
Biswas, R.; Shinar, J.; Shinar, R.; Slafer, W.D,; ”Enhanced Outcoupling of Light FromOLEDS Fabricated On Corrugated Polycarbonate and PET Substrates”, SPIE Conference:
Organic Light Emitting Materials and Devices XXI (Invited Paper, 10362-16), 8 August
2017.