Chemo-resistive sensors

To test this novel architecture as a tool for classification, a simulated experiment was performed. The case of chemo-resistive sensors was considered because of the simple involved electronics. This class of sensors is rather wide and can include sensors based either on inorganic (e.g. metal-oxide semiconductors) or organic (e.g. conducting polymers) sensitive materials. The concepts here illustrated can be extended, with a proper modification of the AORN architecture, to different kinds of chemical sensors. Actually, the features of the olfactive epithelium define the following structure of the AORN. 

As chemo-resistive sensors are based on a change in conductivity at high operating temperatures, so main circuit blocks required for interfacing these sensors are driving circuits for micro-heaters, temperature control units and sensing material interface circuits. 

The sensor is based on high affinity of gold to mercury and on chemo-resistive properties of ultrathin gold layers adsorption of mercury leads to increase in the surface resistance [1,2]. However, this effect is not selective similar changes are caused by adsorption of water vapor and sulfuric compounds. The use of monomolecular layer of alkylthiols as a filter excludes this interference completely [3]. Sensor calibration is performed by thermoinjection of nanogram-amount of mercury quantitatively deposited by electrochemical reduction [4],... 

Jitendra Kumar, Md. Shahabuddin, Arun Singh, S. P. Singh, Parveen Saini, S. K. Dhawan, Vinay Gupta. Highly Sensitive Chemo-resistive Ammonia Sensor Based on Dodecyl Benzene Sulfonic Acid Doped Polyaniline Thin Film. Sci. Adv. Mater. 2015, 7, 518-525 doi 10.1166/sam.2015.2000. 

Rothschild, A. and Komem, Y. (2004) On the relationship between the grain size and gas-sensitivity of chemo-resistive metal-oxide gas sensors with nanosized grains. J. Electroceram., 13, 697-701. 

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