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

The one-step reaction of a dicyanovinyl-functionalized squaric acid with Fischer bases affordedC(2v)symmetric squaraine dyes with rigid planar structures due to intramolecular N-HMIDLINE HORIZONTAL ELLIPSISO 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 cm(2)V(-1)s(-1)and current on/off ratio of 10(6).