Colorimetric gas sensing with enhanced sensitivity

We present a colorimetric gas sensor system using folded sensing elements to obtain miniaturized, highly sensitive gas sensors. Our fabrication method offers the ease of transmission measurements and at the same time a substantial increase in sensitivity. The method is simple and cost-effective compared to waveguide-based solutions. Our colorimetric sensor was characterized using indicator dyes sensitive to ammonia (NH3) and carbon monoxide (CO). The sensing elements are placed between a LED and photodiodes for readout to realize a miniaturized sensor with low-cost components. First results show that by folding the sensing elements the sensitivity can be increased significantly. Ideas to optimize the number of sensing elements and sensor integration are discussed, as well as potential applications.