Polyterthiophenes incorporating 3,4-difluorothiophene units: Application in organic field-effect transistors: Application in organic field-effect transistors

Two terthiophenes bearing core fluorinated thienyl units have been synthesised as potential semiconductor materials for organic field-effect transistors. Polymerisation of these compounds has been achieved using conventional iron(III) chloride oxidative coupling methods and by electrochemical oxidation. Characterisation of the fluorinated materials has been achieved by absorption spectroscopy and cyclic voltammetry. A soluble hexyl-functionalised polymer (poly8b) was used in an OFET device; hole mobilities were measured up to 3 × 10^-3cm²· V^-1·^-1, and the device had an on/off ratio of 10⁵ and a turn-on voltage of +4V. 3,4-Difluoroterthiophenes have been polymerised, and the electronic and redox properties of the resulting polymers are discussed. OFET devices have been fabricated from poly8b using a bottom-gate, bottom-contact configuration. The material gives a maximum hole mobility of 3 × 10^-3cm²·V ^-1·s^-1, and the device has an on/off ratio of 10⁵.