We have investigated hysteresis in pentacene-based field-effect transistors with SiO2 as gate dielectric. A clear hysteresis behavior in transfer and output characteristics is reported. Measurements show that the observed hysteresis is due to hole trapping in the pentacene film. Long time constants of the trapping/detrapping mechanism are demonstrated through transient measurements. An initialization routine to be performed prior to measurements is proposed to enable reproducible and reliable measurements on pentacene transistors.

The authors report on a solution-processed composite film based on poly(vinylidene fluoride/trifluoroethylene) copolymer and barium titanate (BT) nanopowder, to be used as ferroelectric high-κ gate insulation in organic field-effect transistors (OFETs). Flexible films of up to 50vol% BT powder content are produced by preparing homogeneous dispersion of the powder in the polymer solutions. The films exhibited high specific volume resistivities combined with dielectric constants of up to 51.5 at 1kHz. Low-voltage OFETs with ferroelectric hysteresis and good memory retention properties were demonstrated by using the composite films.

This paper presents a detailed study on the properties of different polymer inks based on poly(3,4eth-ylenedioxythiophene)/polystyrenesulfonate regarding their processability in an experimental piezo driven drop-ondemand (DoD) micro-feeding system. Based on the rheological properties of the used inks and the mechanical properties of the printing system characteristic values are derived which allow to predict the processability of polymer inks in a given printing system. Beside the printability the influence of different polymer inks on the electrical characteristics of printed organic field effect transistors is investigated.

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