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

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 sp4 diamond, they exhibit chemical stability greater than sp3 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.