High Volume Zero Power Low Cost PPB Level Printed Nano-Sensors for IoT

Abstract

The sensing capabilities of carbon nanotubes [CNTs] are often reported in the literature (1,2), but we describe here a commercial sensor based on an amperometric detection method using CNT electrodes. The commercial availability means that it has been vetted not only for sensitivity, but also for practical response time, selectivity, and stability in the temperature, pressure and relative humidity (T, P, RH) and time dimensions. The CNT composite electrodes are robust, and while not as inert as the sp 4 diamond, they exhibit chemical stability greater than sp 3 carbons. The significant advantage is the extremely high surface area with virtually every atom a surface atom and therefore high catalytic activity at low loadings. These characteristics are important in high volume sensors so that small size and low cost are enabled along with the inherent low power of electrochemical sensors. This combination of characteristics along with the practical manufacturing by using printed electronics approaches is our key to bridge the cost-performance gap and penetrate high volume consumer and environmental markets with these sensors. The first two environmental gases that use the nano-catalyst electrodes are NO2 and O3 in air at ppb levels.

Challenges and Opportunities for Printed Electrical Gas Sensors

“…Commercially, SPEC Sensors offers printed electrochemical sensors for air quality monitoring. Their sensors appear to exhibit reasonable sensitivity to O 3 (LOD = 0.028 ppm, calculated as 3× the standard deviation of the baseline), CO (<0.250 ppm, from raw data) and NO 2 (0.012 ppm (calculated) and 0.100 ppm (measured)). , The long-term stability (over 8 h), however, is ±0.150 ppm (for O 3 ) which lies above the calculated LOD. This low stability, and the fact that no tests on the influence of changing levels of RH are available, neither from the datasheet nor from publications, makes it hard to estimate the usefulness of these sensors under real-world use cases.…”

Nanostructures for Biosensing, with a Brief Overview on Cancer Detection, IoT, and the Role of Machine Learning in Smart Biosensors

“…Alreshaid and Stetter discussed multiple ink-jet-printed nano-sensors for IoT and smart-city applications [ 187 , 188 ]. Mamun et al described various wearable sensors for environmental monitoring for IoT applications [ 189 ]. Long et al demonstrated low-power gas sensing using 3D porous nanostructured metal-oxide sensors for application related to the IoT [ 190 ].…”

An Electrochemical Amperometric Ethylene Sensor with Solid Polymer Electrolyte Based on Ionic Liquid

“…Ionic liquids (ILs) represent promising media for the next generation of amperometric gas sensors [39][40][41] due to their unique properties such as non-flammability, sufficiently high conductivity, a large electrochemical window, structural modifiability, and excellent thermal stability. It is believed that the negligible volatility of ionic liquids can substantially improve sensor life time; in addition, their electrochemical stability allows the use of a wide range of working electrode potentials for the detection of various target gases.…”