High-Performance 2,8-Difluoro-5,11-bis(triethylsilylethynyl) Anthradithiophene Thin-Film Transistors Facilitated by Predeposited Ink-Jet Blending

We report high-performance ink-jet-printed 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TESADT) organic thin-film transistors (OTFTs) facilitated by polymer blending. The film morphology and crystal structure of diF-TESADT films were greatly improved by printing on a predeposited poly(alpha-methyl styrene) (P alpha MS) layer possibly due to the confined droplet area and thus increased intermolecular interactions. Additionally, partial dewetting and the formation of irregular film shapes were effectively controlled resulting in uniform and improved device performance in the predeposited blending system. Through a proper optimization of printing parameters such as substrate temperature and processing solvent, diF-TESADT TFTs with an average field-effect mobility of 0.34 +/- 0.13 cm(2) V-1 s(-1) (max 0.64 cm(2) V-1 s(-1)) and subthreshold slope of 0.456 +/- 0.090 V decade(-1) have been achieved. (c) 2013 The Japan Society of Applied Physics