High-Performance Organic Electrochemical Transistors Based on Conjugated Polyelectrolyte Copolymers

Philip Schmode, David ohayon, Paul M. Reichstein, Achilleas Savva, Sahika Inal, Mukundan Thelakkat

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


A new generation of polythiophene-based polyelectrolytes is reported to address fundamental issues in organic electrochemical transistors (OECTs). In such devices, the semiconductor must be able to transport and store ions and possess simultaneously a very high electronic mobility. For this, the ion-conducting 6-(thiophen-3-yl) hexane-1-sulfonate tetramethylammonium monomer (THS-TMA+) is copolymerized with the hole-conducting 3-hexylthiophene (3HT) to obtain copolymers, PTHS-TMA+-co-P3HT 1-3 with a gradient architecture. The copolymers having up to 50 mol % 3HT content are easily oxidizable and are crystalline. Consequently, for the copolymers, a higher stability in water is achieved, thus reducing the amount of cross-linker needed to stabilize the film. Furthermore, OECTs using copolymers with 75 and 50 mol % of PTHS-TMA+ content exhibit 2-3 orders of magnitude higher ON/OFF ratio and an extremely lower threshold voltage (-0.15 V) compared to PTHS-TMA+. Additionally, high volumetric capacitance (C∗ > 100 F/cm3) is achieved, indicating that the ion transport is not hampered by the hydrophobic 3HT up to 50 mol %, for which a very high OECT hole mobility of 0.017 cm2/(V s) is also achieved. Thus, the concept of copolymerization to combine both ionic and electronic charge transport in an organic mixed conductor offers an elegant approach to obtain high-performance OECT materials.
Original languageEnglish (US)
Pages (from-to)5286-5295
Number of pages10
JournalChemistry of Materials
Issue number14
StatePublished - Jun 25 2019

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We acknowledge financial support from DFG (GRK 1640) and Bavarian State Ministry for Education, Science and the Arts (Project: SolTech). We thank Jonas Mayer for the illustration of the OECT device, Florian Meichsner and Nicolas Mödl for assistance in synthesis. We also thank Dr. Sabine Rosenfeldt for assistance with the X-ray measurements.


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