Pulsed voltage driven organic field-effect transistors for high stability transient current measurements

In this article, we propose the usage of gate voltage pulses of alternating polarity, to effectively suppress the hysteresis in organic field effect transistors (OFETs). The hysteretic behaviour of poly(3-hexylthiophene-2,5-diyl) (P3HT) based OFETs is systematically investigated by using continuous and pulsed sweep voltage mode. On the basis of the experimental results, both time settings and mode of gate bias voltage influence the carrier transport in the semiconductor channel. Hysteresis-free transfer characteristic curves are obtained by applying diametrically opposed gate pulses of a few milliseconds in duration. Stable on-current transient measurements are also achieved by implementing the pulse mode, thus allowing on-line gas sensing measurements to be successfully performed. Finally, the response of the sensor upon exposure to different concentrations of analyte vapours is found to be in good agreement with the Langmuir adsorption isotherm model.