Effect of divalent metal ion dopants on the physico chemical properties of chromium oxide quantum dots

Abstract

Nanoscience is defined as the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale. In general, the nanomaterials have very large surface area to volume ratio due to their small size which brings out new physical and chemical properties compared to their bulk counterparts. The mechanisms for the property change of the material consist of size dependant quantum confinement effects, change of dimensionality of the system, and so on. In nature, Cr2O3 occurs as the rare mineral eskolaite. The other names of chromium (III) oxides are Chromium sesquioxide, Chromia, Chrome green and eskolaite. Cr2O3 adopts the corundum structure, consisting of a hexagonal close packed array of oxide anions with 2/3 of the octahedral holes occupied by chromium. Similar to corundum, Cr2O3 is a hard, brittle material. It is antiferromagnetic up to 307 K, the Neel temperature. Cr2O3 nano particles appear in the form of green crystals nearly with a spherical morphology. Cr2O3 has band gap energy of 3.30 eV, displays a high refractive index of 2.55 and a high transmittance in the visible region making this material a strong one for use in optoelectronic, electro chemical and spintronic applications. Cr2O3 exhibits photoluminescence which leads the material a promising application in flat panel displays, sensors and LASERs. These nanoparticles are predominantly used as dyes. newline newline newline