Mode of Materials, Technology and Devices

Abstract

Sensors are the fabricated devices that easily respond to any input due to the significant physical alteration in the surrounding atmosphere. The smart performance of a sensor is in correspondence to the sensing material used in its manufacturing. Nanomaterials are the targeted approach and preferable choice of scientists in recent times due to their tremendous desirable characteristics properties in sensing industry.

According to ISO and ASTM standard guidelines, we can define nanomaterials as the materials having the particle size within the range of 1 to 100 nm covering its one, two, or all three dimensions. Nanoparticles can be categorized as organic, inorganic, and carbon-based nanostructured particles with their nanoscale particle size dimensions, which have much advanced and improved characteristics properties as compared to when equal mass of same substance is produced with larger size dimensions. Because of their nanoscale sized particles, nanomaterials as a sensing material show many improved desired properties like sensitivity, stability, durability, swift response/recovery time with respect to input from the change in surrounding atmosphere, low hysteresis, significantly increased surface area, etc. There are various literature reported practices adopted for the synthesis of nanostructured particles, which can be broadly classified into three major categories, namely, physical method, chemical method, and mechanical method of synthesis; each one is intended to produce much amended sensing material. These methods of synthesis are still evolving over the years to produce advanced sensing materials to fabricate smart sensors. Another broad classification of nanoparticles includes various methods into bottom-up and top-down approach of synthesis. Sol-gel, spinning, chemical vapor deposition (CVD), pyrolysis, and biosynthesis methods of synthesis are the part of bottom-up approach, whereas mechanical milling, nanolithography, laser ablation, sputtering, and thermal decomposition methods belong to top-down approach of synthesis. In recent years, due to greater surface area of the synthesized material with hydrothermal and nanocasting, chemical methods of synthesis of nanoparticles are extensively used by researchers and scientists. Further the synthesized nanoparticle is investigated by various characterization techniques like powder X-ray diffraction technique including both low and wide-angle patterns, scanning and transmission electron microscopy, analysis of N2 adsorption and desorption isotherms from BET for enhanced surface area, and energy dispersive X-ray analysis. Finally, this chapter deals with the great utility and applications of the nanostructured particles in various fields.