Crystallization Control of Organic Semiconductors during Meniscus-Guided Coating by Blending with Polymer Binder

Ke Zhang, Tomasz Marszalek, Philipp Wucher, Zuyuan Wang, Lothar Veith, Hao Lu, Hans Joachim Räder, Pierre M. Beaujuge, Paul W.M. Blom, Wojciech Pisula*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Small molecule organic semiconductors (OSCs) suffer from their uncontrolled nucleation and growth during solution processing limiting their functionality in electronic devices. In this work, a new method is presented based on dip-coating a blend consisting of OSC and insulating polymer to control the crystallization of the active film for organic field-effect transistors. A small fraction of amorphous poly(methyl methacrylate) (PMMA) efficiently improves the crystallization of dip-coated small molecule OSCs, α,ω-dihexylquaterthiophene (DH4T) and diketopyrrolopyrrole-sexithiophene (DPP6T). The maximum charge carrier mobilities of dip-coated OSC:PMMA films are significantly higher than drop-cast blend ones and comparable with OSC single crystals. The high charge carrier mobility originates from a continuous alignment of the crystalline films and stratified OSC and PMMA layers. The improved crystallization is attributed to two mechanisms: first, the polymer binder leads to a viscosity gradient at the meniscus during dip-coating, facilitating the draw of solute and thus mass transport. Second, the polymer binder solidifies at the bottom layer, reducing the nucleation barrier height of small molecule OSC. The findings demonstrate that a small fraction of a polymer binder during dip-coating efficiently improves the crystallization as well as the electronic properties of small molecule OSC films.

Original languageEnglish (US)
Article number1805594
JournalAdvanced Functional Materials
Volume28
Issue number50
DOIs
StatePublished - Dec 12 2018

Bibliographical note

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

  • crystallization control
  • dip-coating
  • morphology
  • organic field-effect transistors
  • semiconductor–insulator blends

ASJC Scopus subject areas

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

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