Low-voltage-operated top-gate polymer thin-film transistors with high-capacitance P(VDF-TrFE)/PVDF-blended dielectrics

We report a poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/poly(vinylidene fluoride) (PVDF)-blended film as a high-capacitance polymer-gate dielectric layer for a low-voltage-operated top-gate organic field-effect transistor (OFET). OFETs with poly(9,9-dioctylfuorene-co-bithiophene) (F8T2) as an active layer exhibited a low operation gate voltage of less than 10 V with a reasonable field-effect mobility of 10−4 cm2/V for amorphous conjugated polymers. The operation voltage effectively decreased because of the high permittivity of the P(VDF-TrFE)/(PVDF)- blended film (ε = 10.2). The remnant polarization disappeared completely; further, the hysteresis in the transfer plots induced by the ferroelectric P(VDF-TrFE) was effectively minimized by the disruption of a crystalline β-phase in the film via an increase in the blend ratio of PVDF.