Versatile measurement system for the characterization of gas sensing materials

Abstract

A measurement system designed for the development of novel conductometric gas sensors and of new gas sensing materials is described. The system allows to simultaneously characterize up to 8 sensors. Prototype sensors can be easily realized thanks to an ad hoc structure based on an alumina substrate equipped with electrodes, a heater and an accurate temperature sensor, on this structure the studied material can be deposited by screen printing, spin coating or dip coating. The system is designed to study the behavior of the sensors by accurately setting the operating conditions in terms of chemical environment composition, gas flow, humidity and temperature. The system is fully programmable and it individually controls the film temperatures or measures them with a resolution lower than 0.1 °C. Both chemical transients and thermal transients can be studied. These features make the system suitable for determining the principal performance indexes of a gas sensing device (e.g., sensitivity, stability, selectivity, response/recovery times, etc.) as functions of various combinations of measurement conditions (e.g., gas concentrations, temperature, humidity, flow). The proposed measurement system will find also useful applications in sensor model validation.