Polythiophene-based field-effect transistors with enhanced air stability

We have demonstrated that relatively air stable field-effect transistors (TFTs) with mobility up to 0.01cm2/Vs, near-zero turn-on voltage, and current on/off ratio over 105 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.