Improving baseline stability of gas sensors based on organic field-effect transistors by monitoring carrier mobility

We have investigated the baseline stability of gas sensors based on organic field-effect transistors (OFETs). The time response of the drain current, carrier mobility, and threshold voltage to exposure to humidity were monitored. The extraction of these multiple parameters has so far been reported in order to enhance sensitivity and/or discrimination. We found that the time response of the carrier mobility possesses baseline stability, as opposed to the drain current and threshold voltage. The baseline drifts with time are mainly due to shifts in the threshold voltage that affect the drain current. Our results are expected to assist in making OFET-based gas sensors suitable for practical applications.