Solvent-vapor-annealed A-D-A-type semicrystalline conjugated small molecules for flexible ambipolar field-effect transistors

Min Je Kim, Young Woong Lee, Yujeong Lee, Han Young Woo, Jeong Ho Cho

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


This paper reports a series of acceptor-donor-acceptor (A-D-A)-type small molecules (named P3T4-VCN, P3T4-RCN, and P3T4-INCN) based on an oligothiophene-phenylene core with three different electron-accepting terminal groups - dicyanovinyl (VCN), cyano-rhodanine (RCN), and cyano-indanone (INCN), respectively - for application to flexible ambipolar organic field-effect transistors (OFETs). Intrachain noncovalent coulombic interactions (via S-F and H-F interactions) were incorporated into the design of the P3T4 backbone to enhance the chain planarity. All the P3T4-based OFETs exhibited ambipolar behavior with hole-dominant transport, and the OFET performances were strongly dependent on the terminal groups. The P3T4-INCN OFET exhibited the highest carrier mobility owing to the extended π-conjugation via the INCN moiety, which enhanced the intermolecular cofacial π-π stacking and generated an efficient carrier pathway in the transistor channel. Room temperature solvent vapor annealing resulted in a dramatic increase in the carrier mobility of the OFETs without causing any damage to a polyethylene naphthalate (PEN) plastic substrate. The effects of both the terminal groups of the P3T4 small molecules and solvent vapor annealing were systematically investigated by UV-vis absorption spectroscopy, two-dimensional grazing incidence X-ray diffraction, and atomic force microscopy. In addition, a flexible OFET array with solvent-vapor-annealed P3T4-INCN was successfully fabricated on a PEN substrate. These OFET devices exhibited a hole mobility of 0.15 cm2 V-1 s-1, an electron mobility of 0.05 cm2 V-1 s-1, an on-off current ratio of ∼105, and excellent mechanical stability even after 300 bending cycles.

Original languageEnglish
Pages (from-to)5698-5706
Number of pages9
JournalJournal of Materials Chemistry C
Issue number21
Publication statusPublished - 2018

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation (NRF) of Korea (2016M1A2A2940911, 2015M1A2A2057506, 2017R1A4A1015400, and 2017R1A2B2005790).

Publisher Copyright:
© 2018 The Royal Society of Chemistry.

ASJC Scopus subject areas

  • General Chemistry
  • Materials Chemistry


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