Related Experiment Video
Updated: Oct 30, 2025
10:36
Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating
Published on: April 12, 2018
11.7K
Oligothiophene Phosphonic Acids for Self-Assembled Monolayer Field-Effect Transistors
Baolin Zhao1, Bastian Gothe1, Arthur Groh2
1Organic Materials & Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, IZNF, Cauerstraße 3, 91058 Erlangen, Germany.
ACS Applied Materials & Interfaces
|July 2, 2021
Summary
We developed organic thin-film transistors using semiconducting self-assembled monolayers (SAMs) of thiophene oligomers. Varying oligomer length precisely controlled molecular packing, significantly boosting device performance and charge transport mobility.
Area of Science:
- Materials Science
- Organic Electronics
- Nanotechnology
Background:
- Semiconducting self-assembled monolayers (SAMs) are crucial for organic thin-film electronics.
- They allow precise control over active π-conjugate formation, orientation, and layer thickness.
Purpose of the Study:
- To fabricate and characterize self-assembled monolayer field-effect transistors (SAMFETs) using varying lengths of 3-hexylthiophene oligomers.
- To investigate the relationship between molecular packing, order, and charge transport properties.
Main Methods:
- Fabrication of SAMFETs with phosphonic acid oligomers of 3-hexylthiophene (oligothiophenes-OT) of varying lengths (5, 10, 20 units).
- Analysis of molecular packing and order using X-ray reflectivity (XRR) and quantitative X-ray photoelectron spectroscopy (XPS).
- Electrical characterization of device performance, focusing on charge transport mobility.
Main Results:
- Devices showed stable lateral charge transport, with mobility increasing with thiophene unit count.
- Short oligomers (OT5-PA, OT10-PA) formed highly ordered, near-perpendicular SAMs.
- Long-chain OT20-PA adopted a folded structure, but tuning its molecular order tripled device mobility.
Conclusions:
- Molecular ordering in SAMs is critical for optimizing organic electronic device performance.
- SAMFETs offer a tunable platform for high-performance organic electronics.
- Controlling SAM structure at the molecular level is key to enhancing charge transport.
