Drift reduction of organic coated gas-sensors by temperature modulation
Drift effects and cross sensitivities seriously hinder the application of numerous sensor coatings based on organic or organically modified substances. A temperature modulated mode of sensor operation is investigated to reduce or overcome drift and humidity influence on organic gas-sensitive coatings. The transducers are interdigital capacitance structures with ring heater (IDC). As sensitive material a CO2 sensitive organically modified heteropolysiloxane is used. Heteropolysiloxanes are well known materials for gas-sensing, however, they also have common weaknesses of organic sensor coatings. Using different kinds and patterns of temperature modulation together with adapted signal-processing we were able to greatly reduce long time drift effects and diminsh cross-sensitivities.