Executive Summary : | Numerous layered materials have been found and studied over the past decade and a half, beginning with the discovery of atomically thin carbon called graphene. Among the elemental analogues of graphene, the elements of group 15, called pnictogens have been found to exhibit exotic properties. The applicability of these materials in the technology depends on the clever design of synthetic protocols. This proposal outlines strategies to enable the exfoliation of pnictogen nanosheets from their bulk precursors using scalable techniques, with an added advantage of solution processing.
Liquid phase exfoliation by application of shearing forces to bulk layered crystals offers a viable route to obtaining nanosheet dispersions. The solvents used in the exfoliation step also provide a means of stabilising the nanosheets from reaggregation. The selection of the suitable solvents is of crucial importance in this regard in order to obtain high-quality and stable nanosheets in dispersion. In this regard, Hansen solubility parameters have been instrumental in the determination of good solvents. Through this work, we propose to determine these parameters for pnictogen nanosheets as these have not yet been researched upon. Going beyond just the solubility theory, we further propose that the molecular interaction between nanosheets and solvent molecules would be investigated upon, in order to optimise the rules of solvent selection for liquid exfoliation. This would not only help enable a deeper understanding into the process of solvent exfoliation, but also the flexibility to choose the right solvent for the application at hand which could be of major technological importance.
Various important aspects of solution processing would also be addressed through this work like obtaining size-specific nanosheet dispersions, studies on stability of the dispersions, chemical stability of the nanosheets and aspects pertaining to the scaling up of the processes by the determination of the production rates. By the usage of the synthesised dispersions, solution based device fabrication techniques would be attempted for various applications which would enable a good assessment into the quality of exfoliated nanosheets and their optimisation for the application. This proposal would deepen the understanding of the synthesis, properties and production aspects these nanomaterials along with their implementation into real world applications. |