Sensor manufacturers are routinely innovating their products to drive greater precision in terms of signal detection and device functionality. As many sensors are designed to detect and identify minute or relatively weak indicators, small changes in configuration or material can have a dramatic impact on their performance. Nowhere is this more prevalent than in the gas sensor market, where graphene is being explored extensively for both active sensing elements and substrates in novel sensor arrays.
In this blog post, Grolltex explores some of the potential applications of graphene gas sensors in more detail. First, however, it is worth exploring some of the basic principles of graphene-based gas sensors to gain an appreciation for their pioneering capabilities.
How Do Graphene Gas Sensors Work?
Gas sensors are designed to detect, identify, and/or quantify specific gaseous species in measuring environments. They do so by exploiting an array of mechanisms, such as chemical reactions with metal oxide elements that cause a linear change in electrical resistance. Metal oxide-based sensors are a tried-and-tested method of detecting specific toxic gases, such as carbon monoxide (CO).
When graphene is integrated into a gas sensor, it is done so in one of two ways: monomolecular sheets may be employed as the sensing element which directly interfaces with the measuring environment, or the active element may be deposited onto a substrate of graphene. Each configuration can represent a significant step forward in specific parameters.
The extent to which performance is impacted largely depends on the application area and type of sensor under question.
Ambient Air Quality
Significant research and development (R&D) is already well underway into the use of graphene-based gas sensors for ambient air quality testing, with a focus on monitoring pollution levels. A joint research initiative has developed a low-cost and energy-efficient nitrogen dioxide (NO2) sensor based on a graphene chemiresistor, with sensitivity levels below 10 parts per billion (ppb).
Explosive Gas Detection
The trace level sensitivity of graphene sensing elements to specific gas species has warranted some studies into the potential of detecting gas-phase explosives. Though the real-world applications of this are varied, and the value in terms of health and safety capabilities is undeniable, further research is required to determine their practical efficacy.
Research has extolled the cross-sensitivity of graphene gas sensors to carbon dioxide (CO2) and humidity, showing high selectivity to water vapor in the presence of other atmospheric gases such as argon (Ar), nitrogen (N2), and so on. This is extremely attractive for humidity sensing applications.
Toxic Gas Detection
Much like explosive gas sensing, toxic gas detection is another critical area of study for graphene-based sensors. Theoretically, these could be used to measure virtually any gas species that is harmful to human health at the smallest possible scales. Again, further research is required to determine the real-world performance of these novel gas sensors.
Graphene Gas Sensor Materials with Grolltex
Grolltex is one of the leading manufacturers of two-dimensional materials in the US. We offer pristine graphene monolayers on substrates of our customers choosing, for application in a wide range of market segments. If you would like more information about using our graphene for gas sensors, simply contact a member of the Grolltex team today.