Ethanol Gas Sensors Composed of Carbon Nanotubes with Au Nanoparticles Adsorbed onto a Flexible PI Substrate

Carbon nanotubes (CNTs) are highly interesting materials for gas sensing. In this study, a simple method of directly transferring high-density CNTs from a SiO 2 /Si substrate to a flexible substrate for ethanol gas sensing at room temperature was established. The flexible gas sensor exhibited a high sensitivity of 5.39% at room temperature for the ambient ethanol gas concentration of 800 ppm. The gas response of the CNT-based chemiresistor was attributed to p-type conductivity in the Au-modified semiconducting CNTs. Remarkable repeatability of the sensor response to the gas concentration was demonstrated. These results indicated a major step toward the low-cost, large-scale production of this type of device.