Chemical sensors have been developed over the past decades to detect gases and vapors at various concentration levels for deployment in a wide range of industrial applications. The detection usually centers on a change of a particular property or status of the sensing material, such as temperature, electrical, and optical characteristics. Other types of sensors include electrochemical cells, conducting polymer sensors, surface acoustic wave sensors, and catalytic bead sensors. Sensors based on nanotechnology promise to provide improved performance on all of these sensors compared to current micro and macro sensors.
This invention uses carbon nanotube (CNT) networks as sensors of chemical substances. It provides a chemical sensor or sensor array for detecting the presence, at or near room temperature, of one or more of N target gas components or molecules (N ≥ 1) in a gas mixture contained in a chamber, by any ambient environment being considered. The sensor contains a network of single-wall carbon nanotubes (SWCNTs) that is connected to a controllably variable voltage difference or current source. The chamber may be closed, isolated, and static, or preferably, may allow gas flow-through and thus not be wholly isolated from the external environment. Alternatively, the chamber may be part or all of the external environment.
Carbon nanotubes coated with different polymers and doped with different metal clusters can provide specific interactions with a chemical species of interest. As this chemical treatment aims to provide a specific interaction between the CNT matrix and specific gas molecules, the treatment can improve the selectivity while maintaining the high sensitivity expected of a nanosensor.