Hydrogen bond-rigidified planar squaraine dye and its electronic and organic semiconductor properties

Abstract

The one-step reaction of a dicyanovinyl-functionalized squaric acid with Fischer bases afforded C_2v symmetric squaraine dyes with rigid planar structures due to intramolecular N–H⋯O hydrogen bonds. Dense molecular packing, decrease of HOMO level, and sufficient thermal stability for sublimation enabled vacuum-processed OTFTs with hole mobility up to 0.32 cm² V⁻¹ s⁻¹ and current on/off ratio of 10⁶.