Synthesis, characterization and printing application of alkylated indolo[3,2-b]carbazoles

- Novel alkylated indolo[3,2-b]carbazole compounds are introduced.
- NH⋯π interactions play a crucial role in determining their properties such as OFET behavior and solubility.
- Substitution matters.
- Pneumatic nozzle printing was used for creating crystalline printed thin films.

The synthesis, characterization, and field-effect transistor (FET) properties of new alkylated indolo[3,2-b]carbazole (ICz) based materials are reported. Dialkyl substitution at the 2,8-positions of the ICz core structure do not affect strong NH⋯ π interactions, thus favoring a herringbone packing motif. OFET devices fabricated by compounds of this substitution pattern displayed a charge carrier mobility of ∼10−2 cm2 V s−1. These interactions are suppressed when introducing substituents at the 5,11-positions, resulting in greatly enhanced solubility. A solution processable ICz derivative was finally used in a newly developed pneumatic printing setup to yield a crystalline film with aligned crystals along the printing direction.

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