Conventional metal-oxide gas sensors have non-linear responses and are subject to signal fluctuations and gas cross-sensitivities. These chemiresistors are suitable for general detection they do not provide precision. The researchers used a dielectric excitation technique to achieve SMOX-based gas sensor with a linear response, an enhanced dynamic range and significantly reduced humidity and ambient temperature effects.
The SMOX material used with conventional n-type tin-oxide. It was found that the imaginary part of the a.c. impedance at a certain frequency range provided a linear sensor response over a large range of gas concentrations. The technique was tested against a broad range of volatile gases including: benzene, toluene, hydrogen sulphide, hydrogen, carbon monoxide, methane, ethane, propane, acetylene, methanol, ethanol, acetone and formaldehyde.
As a result, the researchers were able to produce a small-die gas sensor that competes with desktop analytical instrumentation. The material used with conventional n-type tin-oxide.
The results have been reported in Nature Electronics and the paper was featured as the cover story of the May edition.
The authors stated that dielectric excitation approach could be applied to a variety of n- and p-type SMOX materials for application as gas sensors within wearable monitors, autonomous robotics, home health and sensor networks.
Within the paper the authors reported on wireless sensor nodes based on the technology employed for unattended, drone-based and wearable environmental and industrial gas monitoring.
"We have found that by providing electrical excitation of conventional sensing materials in very specific and targeted ways, we can achieve highly desired sensor performance characteristics, unavailable using conventional techniques," said Radislav Potyrailo, a GE Principal Scientist and the lead author of the Nature Electronics article.
The team of researchers will carry on working to better understand the full potential of the dielectric excitation sensor design as well as exploring commercialization opportunities with prospective partners for diverse markets.
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