Karlsruhe Institute of Technology (LTI)

The Device Physics Competence Center is led by the Printed Electronics research group of the Light Technology Institute (LTI) headed by Prof. Uli Lemmer and Dr. Gerardo Hernandez-Sosa from the Karlsruhe Institute of Technology (KIT).

The Printed Electronics group of LTI investigates materials and advanced device architectures for the fabrication of optoelectronic systems by industrially relevant techniques. A central part of the research activities is the development of ink formulations and printing processes to control the performance of printed devices. Moreover, we investigate the integration of printed organic electronic devices in complex systems. Hernandez-Sosa BMBF funded junior research group works on the use of biodegradable/biocompatible materials for the fabrication of optoelectronic devices. The rationale is the combination of state-of-the-art high-throughput printing techniques with the topic of more sustainable and “Greener” technologies. 


In order to fabricate efficient optoelectronic devices (i.e photodiodes, OLEDs, solar cells, etc.) by printing techniques certain requirements should be fulfilled. On the one hand all the layers of the device should be solution processable by printing or coating techniques. On the other hand the process should not inhibit the application-specific functionality of the layer.


The aim of our group is to investigate and optimize application-specific device architectures that could be compatible with industrial processes. Within the group, a range of interests is covered, from inverted structures to ultrathin layer or electrode sytems that enable high performance OLEDs (organic light-emitting diodes), OSCs (organic solar cells), OTFTs (organic thin-film transistors) or OPDs (organic photodiodes).

  • aerosol Jet printing
  • inkjet printing
  • nanoimprint
  • spin-coating
  • optoelectronic characterization

Postdoctoral Researchers

Anthony Morfa, Dr.

Postdoctoral Researcher
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 134 (iL)

Ralph Eckstein, Dr. Ing.

Postdoctoral Researcher
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 134 (iL)

Martin Held, M. Sc.

Postdoctoral Researcher
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 134 (iL)

PhD Students

Nils Juergensen, M. Sc.

PhD student
contact via email

Phone: +49 (0) 6221 54 19 140 (iL)

Tobias Roedlmeier, M. Sc.

PhD student
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 122 (iL)

Stefan Schlisske, M. Sc.

PhD student
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 122 (iL)

Sebastian Stolz, Dipl. Phys.

PhD student
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 134 (iL)

Noah Strobel, M. Sc.

PhD student
contact via email
Room: F 4.13

Phone: +49 (0) 6221 54 19 140 (iL)

Johannes Zimmermann, M. Sc.

PhD student
contact via email

Phone: +49 (0) 6221 54 19 140 (iL)

Florian Mathies, M. Sc.

PhD student
contact via email
Room: E 4.02

Phone: +49 (0) 6221 54 19 140 (iL)

Master & Bachelor

Mervin Seiberlich, B. Sc.

Master student, Heidelberg University
contact via email
Room: E 4.13

Phone: +49 (0) 6221 54 19 140 (iL)

Manuel Pietsch, B. Sc.

Master student, Heidelberg University
contact via email
Room: E 4.13

Phone: +49 (0) 6221 54 19 140 (iL)

Alumni

2014:

  •  Lars Müller (cand. M.Sc.) Heidelberg University
    "Charge Transport in Organic Solar Cells studied by (Photo-) CELIV"
  • Roland Röd (cand. M.Sc.) Heidelberg University
    "Funktionaler Druck mikrooptischer Komponenten eines Sensorsystems"

 2013:

  •  Naresh Kotadiya (M.Sc.) KIT
    "Investigation of Polyfluorenes as electron injections layers in polymer light emitting diodes"
  • Jan Preinfalk (M.Sc.) KIT
    "Modellierung und Optimierung von Hybridelektroden in organischen Solarzellen"
  • Florian Mathies (M.Sc.) Heidelberg University
    "Solution processed n-doped zinc oxide field-effect transistors"
  • Robert Tone (M.Sc.) Heidelberg University
    "Impedance Spectroscopy as a Tool for the Detection of Mixed Layers in Organic Devices"
  • Igal Levin (PhD student) Weizmann Inst. of Science
    Visiting Scientist
  • Christoph Wiesenack (Dipl.Ing.) KIT
    "Inkjet printed active layers for light-emitting electrochemical cells"
  • Stefan Arnold (M.Sc.) Heidelberg University
    "Herstellung und Charakterisierung von lateral strukturierten Kathoden für Lithium-Ionen Akkumulatoren"
  • Paul Faßl (M.Sc.) Heidelberg University
    "Identification and optimization of mixed light emitting layers in phosphorescent multilayer OLEDs"
  •  Jannik Michael Trapp (B.Sc.) KIT
    "Composition and performance mapping of light-emitting electrochemical cells"

2012:

  • Tim Puplinkhuisen (B.Sc.) KIT
    "Herstellung und Untersuchung effizienter flüssigprozessierter OLEDs"
  • Sven Knüppel (Dipl.Ing.) KIT
    "Charakterisierung gedruckter, dünner, funktionaler Schichten und Parameterstudie am Labor- und Seriendruckprozess."

2011:

  •  Tobias Becker (Dipl.Ing.) KIT
    "Schichtdickenmessung an dünnen transparenten Schichten"


  1. ACS Sustainable Chem. Eng. DOI: 10.1021/acssuschemeng.7b00675, April 2017
    Solution-Processed Bio-OLEDs with a Vitamin-Derived Riboflavin Tetrabutyrate Emission Layer
    Nils Jürgensen, Maximilian Ackermann, Tomasz Marszalek, Johannes Zimmermann, Anthony J. Morfa, Wojciech Pisula, Uwe H. F. Bunz, Felix Hinkel, and Gerardo Hernandez-Sosa

  2. Advanced Materials Technologies, vol. 2, no. 2, Feb. 2017.
    Slot Die Coated and Flexo Printed Highly Efficient SMOLEDs
    Sebastian M. Raupp, Dominik Daume, Serpil Tekoglu, Lisa Merklein, Uli Lemmer, Gerardo Hernandez-Sosa, Hans Martin Sauer, Edgar Dörsam, Philip Scharfer, and Wilhelm Schabel

  3. ACS Applied Materials & Interfaces, vol. 9, no. 3, pp. 2776-2785, Jan. 2017.
    Degradation Mechanisms in Organic Light-Emitting Diodes with Polyethylenimine as a Solution-Processed Electron Injection Layer
    Sebastian Stolz, Yingjie Zhang, Uli Lemmer, Gerardo Hernandez-Sosa, and Hany Aziz

  4. Journal of Materials Chemistry C, vol. 4, no. 47 pp. 11150-11156, Nov. 2016.
    One-step additive crosslinking of conjugated polyelectrolyte interlayers: Improved lifetime and performance of solution-processed OLEDs
    Sebastian Stolz, Martin Petzoldt, Naresh Notadiya, Tobias Rödlmeier, Ralph Eckstein, Jan Freudenberg, Uwe H. F. Bunz, Uli Lemmer, Eric Mankel, Manuel Hamburger, and Gerardo Hernandez-Sosa

  5. Scientific Reports 6, Article number: 36643, Nov. 2016.
    Biodegradable Polycaprolactone as Ion Solvating Polymer for Solution-Processed Light-Emitting Electrochemical Cells
    Nils Jürgensen, Johannes Zimmermann, Anthony John Morfa, and Gerardo Hernandez-Sosa

  6. ACS Sustainable Chemistry & Engineering, 4 (12), pp 7050–7055 Sep. 2016.
    Poly(lactic-co-glycolic acid) (PLGA) as Ion-Conducting Polymer for Biodegradable Light-Emitting Electrochemical Cells
    Johannes Zimmermann, Nils Jürgensen, Anthony J. Morfa, Bohui Wang, Serpil Tekoglu, and Gerardo Hernandez-Sosa

  7. Cellulose, vol. 23, no. 110, pp. 1-9, 2016.
    Comparison of biodegradable substrates for printed organic electronic devices
    Anthony J. Morfa, Tobias Rödlmeier, Nils Jürgensen, Sebastian Stolz, and Gerardo Hernandez-Sosa

  8. Advanced Materials, vol. 28, no. 35, pp. 7708-7715, Sep. 2016.
    Digitally Printed Dewetting Patterns for Self-Organized Microelectronics
    Ralph Eckstein, Milan Alt, Tobias Rödlmeier, Philip Scharfer, Uli Lemmer, and Gerardo Hernandez-Sosa

  9. ACS Applied Materials & Interfaces, vol. 8, no. 20, pp. 12959–12967, May 2016.
    High-Performance Electron Injection Layers with a Wide Processing Window from an Amidoamine-Functionalized Polyfluorene
    Sebastian Stolz, Martin Petzoldt, Sebastian Dück, Michael Sendner, Uwe H. F. Bunz, Uli Lemmer, Manuel Hamburger, and Gerardo Hernandez-Sosa

  10. Advanced Functional Materials, vol. 26, no. 18, pp. 3172-3178, May 2016.
    The Swiss-Army-Knife Self-Assembled Monolayer: Improving Electron Injection, Stability, and Wettability of Metal Electrodes with a One-Minute Process
    Milan Alt, Malte Jesper, Janusz Schinke, Sabina Hillebrandt, Patrick Reiser, Tobias Rödlmeier, Iva Angelova, Kaja Deing, Tobias Glaser, Eric Mankel, Wolfram Jaegermann, Annemarie Pucci, Uli Lemmer1, U. H. F. Bunz, W. Kowalsky, G. Hernandez-Sosa, R. Lovrinčić, and M. Hamburger

  11. Macromolecules, vol. 49, no. 8, pp. 2957–2961, Apr. 2016.
    Photo-Cross-Linkable Polyfluorene–Triarylamine (PF–PTAA) Copolymer Based on the [2 + 2] Cycloaddition Reaction and Its Use as Hole-Transport Layer in OLEDs
    Markus Bender, Korwin M. Schelkle, Nils Jürgensen, Stefanie Schmid, Gerardo Hernandez-Sosa, and Uwe H. F. Bunz

  12. Applied Physics A, vol. 122, no. 3, pp. 1-7, Mar. 2016.
    Adjustable passivation of SiO2 trap states in OFETs by an ultrathin CVD deposited polymer coating
    Milan Alt, Christian Melzer, Florian Mathies, Kaja Deing, Gerardo Hernandez-Sosa, and Uli Lemmer

  13. ACS Applied Materials & Interfaces, vol. 8, no. 11, pp. 7320–7325, Feb. 2016.
    Emissive Polyelectrolytes as Interlayer for Color-tuning and Electron Injection in Solution-processed Light-emitting Devices
    Serpil Tekoglu, Martin Petzoldt, Sebastian Stolz, Uwe H.F. Bunz, Uli Lemmer, Manuel Hamburger, and Gerardo Hernandez-Sosa

  14. ACS Applied Materials & Interfaces, vol. 8, no. 7, pp. 4940-4945, Feb 2016.
    Naphthalene tetracarboxy-diimide based n-type polymers with removable solubility via thermally cleavable side chains
    Sabina Hillebrandt, Torben Adermann, Milan Alt, Janusz Schinke, Tobias Glaser, Eric Mankel, Gerardo Hernandez-Sosa, Wolfram Jaegermann, Uli Lemmer, Annemarie Pucci, Wolfgang Kowalsky, Klaus Müllen, Robert Lovrinčić, and Manuel Hamburger

  15. Organic Electronics, vol. 28, pp. 118-122, Jan. 2016.
    Fabrication of polymer solar cells from organic nanoparticle dispersions by doctor blading or ink-jet printing
    Sivaramakrishnan Sankaran, Konstantin Glaser, Stefan Gärtner, Tobias Rödlmeier, Kai Sudau, Gerardo Hernandez-Sosa, and Alexander Colsmann

  16. Langmuir, vol. 31, no. 37, pp. 10303-10309, Sep. 2015.
    Dipolar SAMs Reduce Charge Carrier Injection Barriers in n-Channel Organic Field Effect Transistor

    Malte Jesper, Milan Alt, Janusz Schinke, Sabina Hillebrandt, Iva Angelova, Valentina Rohnacher, Annemarie Pucci, Uli Lemmer, Wolfram Jaegermann, Wolfgang Kowalsky, Tobias Glaser, Eric Mankel, Robert Lovrinčić, Florian Golling, Manuel Hamburger, and Uwe H. F. Bunz

  17. Advanced Electronic Materials, vol. 1, no. 8, p 1500101, Aug. 2015.
    Aerosol-Jet Printed Flexible Organic Photodiodes: Semi-Transparent, Color Neutral, and Highly Efficient

    Ralph Eckstein, Tobias Roedlmeier, Tobias Glaser, Sebastian Valouch, Ralf Mauer, Uli Lemmer, and Gerardo Hernandez-Sosa

  18. Physica Status Solidi B, vol. 252, no. 6, pp. 1272-1279, Jun. 2015.
    Impedance spectroscopy: A method for determining the degree of intermixing in stacks of organic semiconductors
    Robert Tone, Nils Bornemann, Norman Mechau, and Edgar Dörsam

  19. The Journal of Organic Chemistry, vol. 80, no. 1, pp. 582-589, Jan. 2015.
    Soluble Diazaiptycenes: Materials for Solution-Processed Organic Electronics
    Philipp Biegger, Sebastian Stolz, Sebastian N. Intorp, Yexiang Zhang, Jens U. Engelhart, Frank Rominger, Kenneth I. Hardcastle, Uli Lemmer, Xuhong Qian, Manuel Hamburger, and Uwe H. F. Bunz

  20. ACS Applied Materials & Interfaces, vol. 6, no. 22, pp. 20234-20241, Nov. 2014.
    Processing Follows Function: Pushing the Formation of Self-Assembled Monolayers to High-Throughput Compatible Time Scales
    Milan Alt, Janusz Schinke, Sabina Hillebrandt, Marc Hänsel, Gerardo Hernandez-Sosa, Norman Mechau, Tobias Glaser, Eric Mankel, Manuel Hamburger, Kaja Deing, Wolfram Jaegermann, Annemarie Pucci, Wolfgang Kowalsky, Uli Lemmer, and Robert Lovrincic

  21. Review of Scientific Instruments, vol. 85, no. 10, p. 103103, Oct. 2014.
    Motionless system to measure relative angular emission intensity of decaying or modulated light emitting diodes
    Michal Radziwon, Gerardo Hernandez-Sosa, Christoph Lackner, Helmut Sitter, Clemens Simbrunner

  22. Organic Electronics, vol. 15, no. 9, pp. 2135-2140, Sep. 2014.
    Aerosol jet printed top grids for organic optoelectronic devices
    Ralph Eckstein, Gerardo Hernandez-Sosa, Uli Lemmer, and Norman Mechau

  23. Langmuir, vol. 31, no. 37, pp. 10303–10309, Sep. 2015.
    Dipolar SAMs Reduce Charge Carrier Injection Barriers in n-Channel Organic Field Effect Transistors
    Malte Jesper, Milan Alt, Janusz Schinke, Sabina Hillebrandt, Iva Angelova,  Valentina Rohnacher, Annemarie Pucci, Uli Lemmer, Wolfram Jaegermann, Wolfgang Kowalsky, Tobias Glaser, Eric Mankel, Robert Lovrincic, Florian Golling, Manuel Hamburger, Uwe H. F. Bunz

  24. Organic Electronics, vol. 15, no. 9, pp. 2135-2140, Sep. 2014.
    Aerosol jet printed top grids for organic optoelectronic devices
    Ralph Eckstein, Gerardo Hernandez-Sosa, Uli Lemmer, and Norman Mechau

  25. Journal of Materials Chemistry C 2, pp. 7934-7942, Aug. 2014.
    Impact of processing on the chemical and electronic properties of phenyl-C-61-butyric acid methyl ester
    J. Maibach, T. Adermann, T. Glaser, Ralph Eckstein, Eric Mankel, Annemarie Pucci, Klaus Müllen, Uli Lemmer, Manuel Hamburger, T. Mayer, and Wolfram Jaegermann

  26. ACS Macro Letters, vol. 3, no. 8, pp. 788-790, Aug. 2014.
    Printing PPEs: Fundamental Structure–Property Relationships
    Fabian Markl, Ingo Braun, Emanuel Smarsly, Uli Lemmer, Norman Mechau, Gerardo Hernandez-Sosa, and Uwe H. F. Bunz

  27. ACS Applied Materials & Interfaces, vol. 6, no. 9, pp. 6616–22, May 2014.
    Investigation of Solution-Processed Ultrathin Electron Injection Layers for Organic Light-Emitting Diodes
    Sebastian Stolz, Michael Scherer, Eric Mankel, Robert Lovrinčić, Janusz Schinke, Wolfgang Kowalsky, Wolfram Jaegermann, Uli Lemmer, Norman Mechau, and Gerardo Hernandez-Sosa

  28. Advanced Materials, vol. 26, no. 20, pp. 3235–3240, May 2014.
    The Compromises of Printing Organic Electronics: A Case Study of Gravure-Printed Light-Emitting Electrochemical Cells
    Gerardo Hernandez-Sosa, Serpil Tekoglu, Sebastian Stolz, Ralph Eckstein, Claudia Teusch, Jannik Trapp, Uni Lemmer, Manuel Hamburger, and Norman Mechau

  29. Organic Electronics, vol. 15, no. 3, pp. 829–834, Mar. 2014.
    Modelling and simulation of gate leakage currents of solution-processed OTFT
    Stefan Hengen, Milan Alt, Gerardo Hernandez-Sosa, Jürgen Giehl, Uli Lemmer, and Norman Mechau

  30. Organic Electronics, vol. 14, no. 12, pp. 3493–3499, Dec. 2013.
    Gravure printed flexible small-molecule organic light emitting diodes
    Serpil Tekoglu, Gerardo Hernandez-Sosa, Edgar Kluge, Uli Lemmer, and Norman Mechau

  31. Organic Electronics, vol. 14, no. 9, pp. 2223–2227, Sep. 2013.
    The role of the polymer solid electrolyte molecular weight in light-emitting electrochemical cells
    Gerardo Hernandez-Sosa, Ralph Eckstein, Serpil Tekoglu, Tobias Becker, Florian Mathies, Uli Lemmer, and Norman Mechau

  32. Advanced Functional Materials, vol. 23, no. 25, pp. 3164–3171, Jul. 2013.
    Rheological and drying considerations for uniformly gravure-printed layers: towards large-area flexible organic light-emitting diodes
    Gerardo Hernandez-Sosa, Nils Bornemann, Ingo Ringle, Michaela Agari, Edgar Doersam, Norman Mechau, and Uli Lemmer

  33. Applied Physics Express, vol. 5, no. 7, p. 72101, Jul. 2012.
    Ink-Jet-Printed Organic Semiconductor Distributed Feedback Laser
    Xin Liu, Sönke Klinkhammer, Kai Sudau, Norman Mechau, Christoph Vannahme, Johannes Kaschke, Timo Mappes, Martin Wegener, and Uli Lemmer