CMOS Image Sensor as Colorimtric Gas Sensor for Ammonia and Amine Detection

Colorimetric sensor materials change their color upon exposure to analyte gases. In this work, we developed a colorimetric gas sensor based on a CMOS Image Sensor (CIS) for the detection and discrimination of ammonia (NH3) and volatile amines. A low-cost, commercially available CIS is directly functionalized with sensor material and serves as the detector. Therefore, different sensor dyes, integrated into a polyvinyl chloride (PVC) matrix, referred to as sensor materials, are deposited directly on the active pixel area of the CIS. The sensor demonstrates a sensitive and reversible response to NH3, with a wide detection range from 500 ppb to 100 ppm. Furthermore, the sensor successfully discriminates the analytes NH3, diethylamine (DEA), and triethylamine (TEA). Thus, the CIS-based colorimetric sensor is suitable for monitoring the analyte gases and offers advantages in terms of miniaturization and digital readout.