High-Performance Organic Electrochemical Transistors Based on Conjugated Polyelectrolyte Copolymers
Reichstein, Paul M.
KAUST DepartmentBioscience Program
Biological and Environmental Sciences and Engineering (BESE) Division
Embargo End Date2020-07-23
Permanent link to this recordhttp://hdl.handle.net/10754/656757
MetadataShow full item record
AbstractA 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.
SponsorsWe 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.
PublisherAmerican Chemical Societyservice@acs.org
JournalChemistry of Materials