Electronic chip based on self-oriented carbon nanotube microelectrode array to enhance the sensitivity of indoor air pollutants capacitive detection

Highly sensitive capacitive detection is reported for indoor air pollutants, e.g. formaldehyde, toluene, and ammonia gas, at room temperature using an electronic chip with self-oriented carbon nanotube microelectrode array. A remarkable capacitive response is observed owing to the dense entanglement of CNTs and the highly porous 3D structured CNT network on the surface of gold electrode. Such kind of nanotubes can be considered as extended and oriented electrodes. As compared with the effect of spray-casting MWCNTs, the relative capacitance change of the above-mentioned electronic chip is found to increase from 1.8 to 70 by taking ammonia as an example. A model is proposed to explain qualitatively the sensing mechanism of electronic chip.