Effect of non-chlorinated solvents on the enhancement of field-effect mobility in dioctylbenzothienobenzothiophene-based top-gate organic transistors processed by spin coating

Shoya Sanda, Ryousuke Nakamichi, Takashi Nagase, Takashi Kobayashi, Kazuo Takimiya, Yuichi Sadamitsu, Hiroyoshi Naito

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The use of non-chlorinated solvents for film deposition in organic field-effect transistors (OFETs) is highly desirable to fabricate flexible and printable electronic circuits by environmentally friendly processes. Here, we investigate the influence of the use of non-chlorinated solvents, such as toluene, p-xylene, cyclohexanone, and mesitylene, for the deposition of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) films by spin coating on the morphologies of these semiconductor films and the electrical characteristics of OFETs with a top-gate configuration. The results show that the size of polycrystalline domains in spin-coated C8-BTBT films tends to increase as the boiling point (b.p.) of the solvent increases, whereas an improvement in the field-effect mobility is restricted by the decrease in the extent to which the C8-BTBT film covers the substrate due to the long evaporation time of high b.p. solvents. The addition of the high b.p. solvent p-xylene to toluene allows a significant increase in polycrystalline domain sizes in spin-coated C8-BTBT films. Further, spin coating C8-BTBT using the high b.p. solvent mesitylene at a high spin rate is effective for the production of thinner C8-BTBT films with diminished surface roughness. Top-gate C8-BTBT FETs processed by spin coating using a mixed binary solvent and by high-speed spin coating achieved high average field-effect mobilities of 4.9 and 5.4 cm2 V−1 s−1, respectively.

Original languageEnglish
Pages (from-to)181-189
Number of pages9
JournalOrganic Electronics
Volume69
DOIs
Publication statusPublished - 2019 Jun

Keywords

  • Dioctylbenzothienobenzothiophene
  • Organic field-effect transistor
  • Organic solvent
  • Spin coating
  • Top-gate configuration

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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