Air quality monitoring by means of sol-gel integrated tin oxide thin films

Sol-gel pure and Pd-doped SnO2 thin films on integrated substrates were developed to detect NO2 and CO. PdO particles are included in the film matrix and their presence enhances the CO gas sensitivity and response time. Measurements of electrical conductivity showed that these films have a response variation higher than 1000% for NO2 at temperatures in the range of about 200 degrees C with a detection limit near 0.1 ppm, good for air quality monitoring. The response to CO is below 100% of the electrical variation but also in this case the sensor can detect very low concentration level. (C) 1999 Elsevier Science S.A. All rights reserved.