Nanotechnology

Nanotechnology involves itself with the process of creating materials, devices, and systems by manipulating matter at the nanometre scale (1-100 nm). The subsequent application of the materials in the nm scale can be in diverse interdisciplinary fields such as physics, chemistry, biology, medicine, agriculture, etc. The emergence ‘nano-world’ dates back to 1959 when physicist Richard Feynman, postulated with the concept of the nano and articulated “There is plenty of room at the bottom” at a conference of the American Physical Society. Materials of Nanometre scale, i.e., nanomaterials exhibit a large surface-to-volume ratio that leads to an exponential increase in their reactivity. The delocalization tendency of valence electrons participating in chemical bonding varies with the size of the particles. The structure may also alter with the size. These alterations may culminate into variations in the size-dependent physical and chemical properties such as magnetic and optical properties, melting point, specific heat, surface reactivity, bandgap, etc. Nanomaterials are typically classified into four types based on size – 0D, 1D, 2D, and 3D nanomaterials. For 0D nanomaterial, all its dimensions lie within the range of the nanometre scale. A huge boost in manufacturing of nanomaterials has come up, such as quantum dots. 1D nanomaterials have a single dimension that does not conform to nanometre scale range. A large range of 1D nanomaterials includes nanowires, nanorods, etc., which have found its use in various fields. 2D nanomaterials comprise of two dimensions which are not in the nanometre scale range. This class of nanomaterials typically include nanoplates and nanosheets. On the other hand, 3D nanomaterials are generated by the combination of the other three nanomaterial types and exhibit important applications as catalyst and battery electrode materials (such as nanoflowers, nanoballs). Most extensively studied among the nanomaterials are the nanoparticles (NPs), which are composed of three layers: a surface layer (which can be functionalized with a variety of small molecules, metal ions, surfactants and polymers), the shell layer (harbors chemically different composition from the core) and the core (constitutes the central portion of the NP and usually referred to as the NP itself.