Formaldehyde gas sensing chip based on single-walled carbon nanotubes and thin water layer.

We report a unique gaseous formaldehyde sensing chip based on a combination between patterned single-walled carbon nanotube field effect transistors and a precisely controlled aqueous layer with photopolymerized polyelectrolytic gels. The proposed system reliably detects 0.1 ppb level formaldehyde gas, suggesting a new type of indoor air quality monitoring device.