Organic semiconductors in potentiometric gas sensors

Solid-state potentiometric sensors based on the chemical modulation of the work function of organic semiconductors are discussed. The theory of the chemical work function modulation is briefly reviewed. There are several sensor configurations, in which this transduction principle can be employed. First is the Kelvin probe, second is the chemically sensitive field-effect transistor in which the conventional metal gate of the silicon-based transistor has been replaced by an organic semiconductor. Chemical modulation of work function enters also into the operation of the third type of sensor discussed in this review, on “organic field-effect transistor”. It is shown that in reality such sensors are “field-modulated chemiresistors”, rather than potentiometric sensors.