Screen-Printable Colorimetric Sensors for the Monitoring of Toxic Gases in Ambient Air

We present a fast and simple method to monitor toxic gases in ambient air based on a visible color change of a printed paper sensor, which can be evaluated using a camera (e.g. smartphone) or naked eye. This study focuses on the development of gas-sensitive pastes for the processing of the colorimetic material by screen printing. Indicators for the detection of ammonia (NH3 ), hydrogen sulfide (H2S) and formaldehyde (CH2O) were examined in closer detail. The sensing properties of the respective indicator towards the target gas was characterized via UV/Vis spectroscopy in reflection.