Abstract
Ph.D. (Chemistry)
Nano-engineered chalcogen materials have garnered importance among the researchers
across all scientific disciplines because of their interesting properties as well the possibility to
tailor their electric, optical, thermal and mechanical properties via controlling shape and size.
Various chalcogen based nanostructured materials such as Co3O4, MoO3, MoS2, NiS, WS2,
WSe2, MoSe2, Bi2Te3, Ag2Te etc have found improved applications in energy conversion and
storage devices, electronics, catalysis, sensors, solid lubricants and topological insulators etc.
Still, these nanostructured materials have not been much explored for environmental and
biomedical aspects although they have immense potential. The expensive and complicated
fabrication techniques and perplexity of surface modification are the critical reasons which
limit their utility in desired applications. Most of the previously reported synthesis techniques
have also no control over issues such as structural composition, variant size and
morphologies. However, different shapes and size dependent properties of nano-engineered
chalcogen materials are yet to be explored.
Thereby, this study addressed the facile strategies to design and develop new materials and
structures with controlled morphologies, size, and composition of nano-engineered chalcogen
materials via the wet chemical route. The evolved physiochemical properties based on their
structural dimensions were also investigated. The effect of various reaction parameters such
as the ratio of precursors, precursor concentrations, the role of stabilising/capping agent and
new precursors on the composition and morphological evolution of the chalcogen based
nanomaterials have been systematically explored. The developed liquid phase synthesis
methodologies of nano-engineered chalcogen materials were facile, economical, energy
efficient and eco-friendly. The structural, compositional and morphological features of
fabricated chalcogen based nanomaterials were studied using various analytical instruments
such as SEM/EDX, HRTEM, XRD, TGA, XPS, UV-Vis, FT-IR and Raman. Furthermore,
this research also focused on harnessing the full potential of these synthesised nanomaterials
in environmental and biomedical applications based on the information of physiochemical
properties. Some applications that are covered in the environmental field are adsorption,
photocatalysis and nanophosphors, whereas the biomedical field includes mainly cytotoxic
behaviour of nanomaterials.
The highlights of results obtained from the PhD study are summarised as follows.
Part I presents a study of the anions ratio effect of acetate and nitrate ions on the formation
of the different morphology of ZnO crystals in presence of NaOH and HMTA. The...