Graphene-based sensor targets sick building syndrome
Whether it's off-gassing from the paint on the walls, the carpet on the floor or the furniture in the room, there are numerous sources of indoor air pollution that can ultimately lead to so-called "sick building syndrome." There are already devices that can detect such pollutants, although their sensitivity is generally limited to concentrations of parts-per-million. Now, however, scientists have created a sensor that can detect airborne CO2 molecules and volatile organic compound (VOC) gas molecules down to parts-per-billion.
Developed by researchers from the University of Southampton and the Japan Advanced Institute of Science and Technology (JAIST), the device is centered around a suspended strip of graphene with a weak electrical field being run through it. For those who don't know, graphene is a one-atom-thick sheet of carbon atoms, linked together in a honeycomb pattern.
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When individual CO2 or VOC molecules bond with the graphene and are then subsequently released (processes known adsorption and desorption), the electrical resistance of the graphene is affected. The sensor is able to detect those changes, and can thus determine the concentration of any such substances that are present in the environment.
In lab tests, a prototype was able to detect CO2 gas in a concentration of about 30 ppb (parts-per-billion), within minutes of the gas being released into a room.
As an added bonus, because the sensor is very compact, it could lead to much lighter and cheaper pollution-detecting devices. Additionally, it's very energy-efficient, requiring less than three volts to operate.
Source: University of Southampton