Preparation of Poly(3,4-ethylenedioxythiophene) Films on Piezoelectric Quartz Crystal and Their Gas Sensitivities

This paper describes the development and the results of a Quartz Crystal Microbalance (QCM) sensor for NO2 detection with the sensitive layer made of a thin film of poly (3,4-ethylenedioxythiophene) PEDOT. The PEDOT was obtained by electropolymerization on one of the gold electrodes of a 10 MHz AT-cut commercial quartz crystal. The sensor performance in terms of sensitivity and selectivity were assessed exploiting an ad hoc chemical sampling unit, and a low noise conditioning and processing electronic system. The preliminary obtained results show a NO2 resolution and sensitivity of the order of 1 ppm, and 2.6 Hz/ppm, respectively, at 35°C constant room temperature and 0% relative humidity, and show that a satisfactory repeatability can be achieved with recovery cycles in N2 at room temperature.