Dithienosilole- and dibenzosilole-thiophene copolymers as semiconductors for organic thin-film transistors

The synthesis and physicochemical properties of a new class of thiophene/arenesilole-containing π-conjugated polymers are reported. Examples of this new polymer class include the following: poly(2,5-bis(3′,3′′-dihexylsilylene-2′,2′′-bithieno)thiophene) (TS6T1), poly(2,5′-bis(3′′,3′″-dihexylsilylene-2′′,2′″-bithieno)bithiophene) (TS6T2), poly(2,5′-bis(2′′,2′″-dioctylsilylene-1′′,1′″-biphenyl)thiophene) (BS8T1), and poly(2,5′-bis(2′′,2′″-dioctylsilylene-1′′,1′″-biphenyl)bithiophene) (BS8T2). Organic field-effect transistors (OFETs) with hole carrier mobilities as high as 0.02-0.06 cm²/V s in air, low turn-on voltages, and current on/off ratios >105-106 are fabricated using solution processing techniques with the above polymers as the active channel layer. OFETs based on this polymer class exhibit excellent ambient operational stability.