Executive Summary : | Two dimensional materials or layered materials like graphite, transition metal dichalcogenides (TMDCs) etc., are a novel class of crystals which exhibit strong in-plane and weak out-of-plane bonding with adjacent layers held together by van der Waals interactions. When thinned down to mono and few-layers, they depict superior electrical, magnetic, optical and mechanical properties than their bulk counterparts. Liquid phase exfoliation (LPE) is a viable route to produce dispersions at ambient conditions with high production rates and also offers much needed scalability. The nature of atomic units governs the nanomaterial geometry obtained after exfoliation. In layered materials like TMDs, 2D monolayer units delaminate into nanosheets, 1D atomic units in materials like Sb2X3 (X = S, Se) and M2Se9 (M = V, Nb) form nanowires. Recently, non-layered non van der Waals (NL-NvdW) materials like haematite, ilmenite, Ge, Fe2O3, FeF3, and α-WO3, which possess stronger covalent bonding in all directions implying that there is no preferred atomic plane for selective cleavage, which could lead to selectivity in dimensionality of obtained nanomaterials, have been shown to exfoliate selectively into nanoplatelets through LPE. The exposed crystallographic planes of solution processed nanomaterials were identified via TEM analysis and were found to be in agreement with theoretically predicted preferred cleavage planes. Thus, the selectivity for dimensionality of nanomaterials post processing appears to be function of bonding anisotropy or relative basal plane cleavage energies in bulk crystal structures. This correlation between the bonding anisotropy and dimensionality of processed materials is missing in the literature. Our aim is to exfoliate series of NL-NvDW materials with wide range of bonding anisotropy in order to establish a correlation among the relative basal plane cleavage energies and the geometry obtained. To exfoliate non-layered materials, liquid phase exfoliation techniques like shear mixing, ultrasonication, or homogenisation will be employed. Detailed physicochemical characterisation of dispersions will be carried out to identify parameters like, size distribution, aspect ratios, yields, exposed crystallographic planes, and phase purity. Computational analysis of optimal surface terminations, relative basal plane cleavage energies, and static and dynamic exfoliation energies will be carried out and a correlation between experimental and computational results will be established from the perspective of bonding anisotropy in respective crystal structures. For detailed study on stability of dispersions, dispersion analyser will be utilised for computing parameters like instability index and shelf life. Obtained dispersions will be employed for fabrication of devices to explore utility of these materials in various applications ranging from electrochemical energy storage and conversion to optoelectronics or sensors. |