Institute For The Future

DIY: split your nanotube and make an ultrafine chemical sensor

An article at PhysicsWeb describes an organic molecular transistor that can be used as an ultrasensitive chemical sensor. The transistor is a single-walled carbon nanotube with a 2 to 6 nm gap cut in it. A voltage is then applied along the nanotube and polycyclic aromatic hydrocarbons self-assemble a structure to fill the gap. The conductivity of these molecules is very sensitive to the chemical environment: "when the device was exposed to electron-deficient molecules such as tetracyanoquinodimethane (TCNQ), the conductivity of the hydrocarbons was found to increase so much that the current passing through the transistor goes up by an order of magnitude....They also say the device could be used to detect chemicals in air or even be immersed in liquids."