Polythiophene-based field-effect transistors with enhanced air stability

We have demonstrated that relatively air stable field-effect transistors (TFTs) with mobility up to 0.01 cm(2)/V s, near-zero turn-on voltage, and current on/off ratio over 10(5) could be fabricated in entirety under ambient conditions with poly(3',4'-dialkyl-2,2'5',2-terthiophene) as active channel layer. This class of polythiophenes, which comprise of regioregularly arranged 2,5-thienylene and disubstituted-2,5-thientylene moieties, have shown enhanced stability against p-doping by atmospheric oxygen. When exposed to atmospheric oxygen, the unprotected TFTs fabricated with these materials had exhibited significantly higher stability than those of regioregular poly(3-hexylthiophene)s under similar conditions. (C) 2003 Elsevier B.V. All rights reserved.