Phthalocyanine-based field-effect transistor as ozone sensor

In this paper, we present a new sensor, which exhibits a sensitivity to ozo ne to less than 10 ppb. The device is a phthalocyanine-based field-effect t ransistor which is capable of working at room temperature. We describe a dy namic procedure, working out of the equilibrium state, to get rid of drift phenomena. A process where 2 min exposure alternates with 8 min static rest period leads, after a conditioning period, to a stable and reproducible si gnal. The response of the device (55 pA ppb(-1) min(-1)) is linearly correl ated to the ozone concentration in air, in the range 0-150 ppb. The use of a dynamic rest (flow of ozone free air) instead of a static rest reduces th e duration of the recovery period, but is not necessary to achieve a good r eproducibility. (C) 2001 Elsevier Science B.V. All rights reserved.