Journal of Coatings Technology and Research

, Volume 14, Issue 5, pp 1029–1037 | Cite as

Slot die-coated blue SMOLED multilayers

  • Sebastian M. RauppEmail author
  • Lisa Merklein
  • Sebastian Hietzschold
  • Martin Zürn
  • Philip Scharfer
  • Wilhelm Schabel


The key challenge in solution-processing efficient OLEDs is to realize the multilayer device architecture. We demonstrate that slot die coating is applicable to deposit small-molecule (SM) layers on top of each other without dissolving the underlying layer. A stack for a blue SMOLED is chosen comprising slot die-coated PEDOT:PSS, an SM emissive layer (EML) as well as an SM electron transport layer (ETL). The devices are fabricated in a sheet-to-sheet coating process with a slot die table coater under ambient conditions. While keeping the processing parameters constant for PEDOT:PSS and the EML, the composition of the ETL is varied. The choice of solvent for coating the ETL is crucial regarding wetting and dissolution of the underlying layer, solubility, surface roughness, and device efficiencies. Average roughness values down to 0.38 nm and peak to valley values around 10 nm were measured. Comparing device efficiencies of devices with and without ETL, an increase in efficiency with a factor up to 42 was achieved. In total, we show 135 blue SMOLEDs to demonstrate reproducibility.


Slot die coating OLED SMOLED Multilayer Solution processed Organic electronics Drying Film morphology AFM 



Acetic acid




Current efficiency


Emissive layer


Electron transport layer




Formic acid




Hole blocking layer


Hole injection layer


Hole transport layer








Power efficiency











The authors acknowledge financial support via the project Print OLED (Contract Number 13N10759) and POESIE (Contract Number 13N13692) of the Federal Ministry of Education and Research. We would like to thank all involved mechanics, assistants, and our students for contributing to this work as well as TSE Troller AG, Murgenthal, Switzerland, for technical support. The authors are also thankful for the support of the Light Technology Institute (LTI) of KIT as well as the Institute of Printing Science (IDD) of the Technical University of Darmstadt and InnovationLab GmbH, Heidelberg.

Supplementary material

11998_2017_9964_MOESM1_ESM.pdf (344 kb)
Supplementary material 1 (PDF 343 kb)


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Copyright information

© American Coatings Association 2017

Authors and Affiliations

  • Sebastian M. Raupp
    • 1
    • 2
    Email author
  • Lisa Merklein
    • 1
    • 2
  • Sebastian Hietzschold
    • 2
    • 3
  • Martin Zürn
    • 1
    • 2
  • Philip Scharfer
    • 1
    • 2
  • Wilhelm Schabel
    • 1
  1. 1.Institute of Thermal Process Engineering, Thin Film TechnologyKarlsruhe Institute of TechnologyKarlsruheGermany
  2. 2.InnovationLab (iL)HeidelbergGermany
  3. 3.Institute for High-Frequency TechnologyTU BraunschweigBrunswickGermany

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