Synthesis Characterization and Properties of Polymer Nanocoomposites

Abstract

Nanoscience and nanotechnology is an emerging and promising field of research, which has been thriving in many areas during the recent decade, including materials science, machines, electronics, optics, medicine, energy and aerospace. Nanotechnology aims at manipulating atoms, molecules and nanosized particles in a precise and controlled manner in order to build materials with a fundamentally new organization and novel properties. Research in this field has been driven by the desire to fabricate material with novel or improved properties. Nanostructures exhibit scientifically interesting phenomena and desirable engineering characteristics. Nanostructured materials are assemblies of nano-sized units which exhibit remarkable properties vastly different and superior to those of the conventional coarse grained materials. Two of the major factors in this case are the increase in the ratio of surface area to volume and the size of the newlineparticle moving into the realm where quantum effects predominate. Study on new physical properties and application of nanomaterials are possible only when they are made available with desired size, morphology, crystal and microstructure and chemical composition. newlineThe present doctorate work is an attempt to understand an important branch of nanoscience -properties of semiconducting nanocrystalline (CdSe) dispersed in PVA matrix and devices based on these materials. In semiconductor nanocrystals of II-V1 materials such as CdSe the combination of bulk and molecular properties results in a rich photophysics that is not only interesting, but is also very promising for the development of solid state devices. CdSe as core is interesting materials and it has a typical direct band gap [Eg = 1.75 eV] semiconductor, which has been a model material in the studies of quantum size effects. By appropriate choice of CdSe nanocrystal size, the absorption edge can thus be made to fall anywhere in visible region. The entire work presented in this thesis has been classified into four chapters each of which