Size and shape-controlled growth of CoFe2O4 nanoparticles for magnetic properties and humidity sensing applications

Abstract

Recently, nanoscience and nanotechnology is a critical driving force for globalization and commercialization of various technological applications. Nanoscience is one of the most important research in modern science. Nanoscience is the study of phenomena and manipulation of materials at atomic, molecular, and macromolecular scales, where properties differ significantly from those at a larger scale. Nanotechnology allows scientists, engineers, and chemists to design, characterize, and produce the application oriented structures, devices, and systems by controlling shape and size on the nano scale level [1]. Nanoparticles (NPs) have drawn much attention from the last few years due to their unique chemical and physical properties distinct from the bulk materials [1]. Generally, NPs are referred to a size less than 100 nm in dimension. At nanoscale dimensions, an increasing fraction of atoms lie near or on the surface, and interfacial regions make the effect of the surface and interface electronic structure more and more important [2]. Compare to microparticles or bulk, NPs have a very large surface area [2]. These factors affect the chemical reactivity of materialsas well as their mechanical, optical, electric, and magnetic properties [3]. For example, electrical conductivity increases due to the better ordering and ballistic transport; optical absorption peak of semiconductor NPs shifts to shorter wavelength due to an increase in band gap; metallic NPs color changes in spectra due to surface plasmons resonances; mechanical strength enhances simply as size decreases due to reduced probability of defects; increased selectivity and reactivity in catalysis as size decreased [4–8]. The range of applications, where the size and shape of the particle can enhance properties, is extremely wide and useful for various technological applications.