Thieno[3,2-b]thiophene flanked isoindigo polymers for high performance ambipolar OFET applications

Iain Meager*, Mark Nikolka, Bob C. Schroeder, Christian B. Nielsen, Miquel Planells, Hugo Bronstein, Joseph W. Rumer, David Ian James, Raja Shahid Ashraf, Aditya Sadhanala, Pascal Hayoz, Jean Charles Flores, Henning Sirringhaus, Iain McCulloch

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

86 Scopus citations

Abstract

The synthesis of a new thieno[3,2-b]thiophene isoindigo (iITT) based monomer unit, and its subsequent incorporation into a series of alternating copolymers is reported. Copolymerisation with benzothiadiazole, bithiophene and thiophene comonomer units by palladium catalysed cross coupling gives three new narrow band gap semiconducting polymers for OFET applications. Extending the fused nature of the isoindigo core serves to further enhance molecular orbital overlap along the polymer backbones and facilitate good charge transport characteristics thus demonstrating the potential of extending the fused ring system that is attached to the isoindigo core. When used as the semiconducting channel in top-gate/bottom-contact OFET devices, good ambipolar properties are observed, with hole and electron mobilities up to 0.4 cm2/Vs and 0.7 cm2/Vs respectively. The three new polymers show good stability, with high temperature annealing showing an increase in the crystallinity of the polymers which corresponds directly to charge carrier mobility improvement as shown by X-ray diffraction, atomic force microscopy and photothermal deflection spectroscopy.

Original languageEnglish (US)
Pages (from-to)7109-7115
Number of pages7
JournalAdvanced Functional Materials
Volume24
Issue number45
DOIs
StatePublished - Dec 3 2014
Externally publishedYes

Keywords

  • Conjugated polymers
  • Isoindigo
  • OFET
  • Thieno [3,2-b]thiophene

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

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