Abstract
In this research, we combine the printed electrodes and flexible substrate to develop a low-cost resistive gas sensor with low energy-consumption. After coating a thin layer of polymer and carbon black mixture, the ability of measuring gas can be derived by analyzing the resistance change due to the adsorption of the gas molecules by the polymer. The sensor array containing seven sensors can be coated with different polymer so that every polymer will response to gas differently. The goal of identifying or classifying gases can be reached by analyzing the resistance change.The integrated gas sensor not only can monitor those harmful volatile organic compounds and explosive gases real-time and also being part of the Internet of Things acting as the application of smart wearable devices. Eight different combination of electrode’s width and gap are designed. ITRI helps to do the printing fabrication on the glass and PET substrates. One of the developed sensing materials PNVP is coated on the chips and tested by ethanol and methane. The most sensitive design of electrode’s width/gap is 20μm/20μm.The LOD towards ethanol is 40ppm and 32ppm for methane. The resistance change of the two gases is opposite. Besides PNVP, sensors coated with other polymers such as P4VP and PS are measure by different concentration of gases and derive the sensitivity of each. Since the substrate is flexible, bending influence to sensor is also considered.The stability test, reproducibility test are performed as well. Through these experiments, the gas sensor has great potential to achieve the purpose of establishing a wearable sensing platform.