The sensor detects individual carbon dioxide (CO2) molecules and volatile organic compound (VOC) gas molecules found in building and interior materials, furniture and even household goods, which adversely affect our living in modern houses with good insulation.
These harmful chemical gases have low concentrations of ppb (parts per billion) levels and are extremely difficult to detect with current environmental sensor technology, which can only detect concentrations of parts per million (ppm).
In recent years, there has been an increase in health problems due to air pollution in personal living spaces, known as sick building syndrome (SBS), along with other conditions such as sick car and sick school syndromes.
By monitoring the electrical resistance of the graphene beam, the adsorption and desorption (whereby a substance is released from or through a surface) processes of individual CO2 molecules onto the graphene were detected as 'quantised' changes in resistance (step-wise increase or decrease in resistance).
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"In contrast to the commercially available environmental monitoring tools, this extreme sensing technology enables us to realise significant miniaturisation, resulting in weight and cost reduction in addition to the remarkable improvement in the detection limit from the ppm levels to the ppb levels," said Professor Hiroshi Mizuta, from the University of Southampton and JAIST, who led the study along with Muruganathan.
The researchers have also recently developed graphene-based switches using a uniquely thin film.
The researchers now aim to bring the two technologies together to create ultra-low-power environmental sensor systems that can detect single molecules.
The study was published in the journal Science Advances.