Laser-Deposited Carbon Aerogel Derived from Graphene Oxide Enables NO 2 -Selective Parts-per-Billion Sensing

Laser-deposited carbon aerogel is a low-density porousnetwork of carbon clusters synthesized using a laser process. A one-stepsynthesis, involving deposition and annealing, results in the formation of athin porous conductive film which can be applied as a chemiresistor. Thismaterial is sensitive to NO2 compared to ammonia and other volatile organiccompounds and is able to detect ultra-low concentrations down to at least 10parts-per-billion. The sensing mechanism, based on the solubility of NO2 inthe water layer adsorbed on the aerogel, increases the usability of the sensorin practically relevant ambient environments. A heating step, achieved intandem with a microheater, allows the recovery to the baseline, making itoperable in real world environments. This, in combination with its low costand scalable production, makes it promising for Internet-of-Things air quality monitoring.